UM10437
GreenChip 65 W TEA1738LT/T and TEA1703 demo board
Rev. February 2011 User manual
Document information Info Keywords Abstract Content Notebook adapter, TEA1738LT/T, TEA1703, fixed frequency, ultra-low standby power, high-efficiency, slim line This manual provides the specification, schematics and PCB layout of the 65 W TEA1738LT/T and TEA1703 demo board. For details on the TEA1738LT/T or TEA1703 IC please refer to the application note.

NXP Semiconductors

Revision history Rev v.1 Date 20110228 Description first issue

Contact information

For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com
UM10437 All information provided in this document is subject to legal disclaimers. NXP B.V. 2011. All rights reserved.

User manual

Rev. February 2011

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1. Introduction
WARNING Lethal voltage and fire ignition hazard The non-insulated high voltages that are present when operating this product, constitute a risk of electric shock, personal injury, death and/or ignition of fire. This product is intended for evaluation purposes only. It shall be operated in a designated test area by personnel qualified according to local requirements and labor laws to work with non-insulated mains voltages and high-voltage circuits. This product shall never be operated unattended.
This 65 W TEA1738LT/T and TEA1703 demo board demonstrates the capabilities of the TEA1738LT/T Switched-Mode Power Supply (SMPS) controller and the TEA1703 standby controller. This manual provides the specification, schematics and PCB layout of the 65 W TEA1738LT/T and TEA1703 demo board. Refer to the TEA1738LT/T data sheet and application note (AN10981) for details on the TEA1738LT/T. In addition, refer to the TEA1703 datasheet and application note (AN11012) for details on the TEA1703. In Standby mode operation (no-load condition), the TEA1703 standby control IC monitors the output voltage and disables the primary controller until the output voltage has reached its lowest preset value. This ensures ultra-low standby power consumption.

019aab616

Fig 1.
TEA1738LT/T and TEAW demo board

1.1 Features

Universal mains supply operation OverCurrent Protection (OCP) OverPower Protection (OPP) Low ripple and noise Slim line transformer
All information provided in this document is subject to legal disclaimers. NXP B.V. 2011. All rights reserved.

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Low-cost implementation Indicator LED Ultra low no-load standby power (< 50 mW at 230 V, 50 Hz) ENERGY STAR compliant EMI CISPR22 compliant
2. Power supply specification
Table 1. Symbol Vi fi Pi(no_load) Table 2. Symbol Vo Vo(min) Vo(ripple)(p-p) Io Io(p) Po tholdup tstartup Input specification Description input voltage input frequency input power (no-load) Output specification Description output voltage Minimum output voltage peak-to-peak output ripple voltage output current peak output current output power hold-up time line regulation load regulation start-up time efficiency EMI Conditions during standby mode operation 20 MHz bandwidth continuous for 50 ms 0 to 40 C at 115 V; 60 Hz; full load at 115 V; 60 Hz according to ENERGY STAR (EPS 2) CISPR22 compliant Specification to 3.pass Unit V V mV A A W ms % % s % Conditions at 230 V; 50 Hz Specification 90 to to 60 < 50 Unit V Hz mW

3. Performance data

Performance figures based on the following PCB design:
Schematic version: Tuesday 18 November 2010 rev. A 3.1 Efficiency
Efficiency measurements were made using an automated test program containing a temperature stability detection algorithm. The output voltage and current were measured using a 4-wire current sense configuration directly at the PCB connector. Measurements were performed for 115 V; 60 Hz and 230 V; 50 Hz.

All information provided in this document is subject to legal disclaimers.
NXP B.V. 2011. All rights reserved.

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Efficiency results[1][2] ENERGY Efficiency (%) STAR 2.0 Average 100 % 75 % efficiency load load requirement (%) > 87 > 87 90.3 91.6 88.8 91.6 90.5 92.% load 100 % 1 W load 0.5 W 0.25 W

Table 3. Condition

115 V, 60 Hz 230 V, 50 Hz

[1] [2]

90.4 91.7

90.5 90.9

76.8 74.8

69.1 66.4

57.8 54.3
Warm-up time: 10 minutes There is an efficiency loss of 1 % (approximately) when measured at the end of a 1 m output cable.

A V Cable

014aab147

DC current source

Fig 2.
DC resistance output cable
DC resistance cable = voltage drop / current = 0.228 / 3.349 = 0.0681 (2-way).
3.2 No-load power consumption
Power consumption performance of the total application board with no-load connected was measured using a Yokogawa WT210 digital power meter. Integration time was set to 6 minutes to calculate the average dissipated power. The output voltage variation results are shown in Table 4. Measurements were performed for 90 V; 60 Hz, 115 V; 60 Hz, 230 V; 50 Hz, and 264 V; 50 Hz.
Table 4. Condition 90 V; 60 Hz 115 V; 60 Hz 230 V; 50 Hz 264 V; 50 Hz Output voltage and power consumption: no-load ENERGY STAR 2.0 requirement (mW) Output voltage high (V) 19.8 19.8 19.8 19.8 Output voltage low (V) 14.2 14.2 14.2 14.2 No-load power consumption (mW) 39 56
3.3 Minimum output current in normal operation
The minimum current required to leave Standby mode and enter normal operation was measured for 90 V; 60 Hz and 264 V; 50 Hz.
Table 5. Condition Current (mA) Minimum current for normal operation 90 V; 60 Hz V; 50 Hz 5

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3.4 Output regulation
The output voltage as a function of load current was measured using a 4-wire current sense configuration directly at the PCB connector. Measurements were performed without probes attached to the application for 115 V; 60 Hz and 230 V; 50 Hz.

20.0 Vo (V) 19.8

019aab617

(1) (2)

Io (A)
(1) Vo = 115 V (AC); 60 Hz. (2) Vo = 230 V (AC); 50 Hz.

Fig 3.

Output voltage regulation as function of current load

3.5 Line regulation

The output voltage as a function of mains input voltage was measured directly at the output connector for full load (3.34 A) condition.

19.75 Vo (V) 19.65

019aab618

265 mains (Vac)

Fig 4.
Output voltage as function of mains voltage

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3.6 Output voltage regulation in Standby mode
The output voltage regulation during no-load operation was measured for 90 V; 60 Hz and 264 V; 50 Hz.

019aab619

Chan1 (yellow): VCC; Chan2 (green): Gate pulse; Chan3 (magenta): VO

Fig 5.

Output voltage regulation at no-load 90 V; 60 Hz

019aab620

Fig 6.
Output voltage regulation at no-load 264 V; 50 Hz

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3.7 OverPower Protection (OPP)
Nominal and peak output power was measured directly at the output connector for various mains input voltages. Peak output power was measured after removing C18 and replacing R16 for 180 k.

150 Po (W) 130

019aab621

mains (Vac)

(1) Nominal power (W). (2) Peak power (W).

Fig 7.

Nominal and peak output power as function of mains voltage

3.8 VCC voltage

The IC VCC pin 1 voltage was measured for both no-load and full load (3.34 A) conditions.
Table 6. Condition No-load Full load (3.34 A) VCC voltage 115 V; 60 Hz 18.230 V; 50 Hz 19.0 20.2
3.9 Brownout and start level
Brownout and start level was measured for no-load and full load (3.34 A) conditions.
Table 7. Condition No-load Full load (3.34 A) Brownout and start level results Brownout V (AC) Start level V (AC) 84 85
3.10 OverVoltage Protection (OVP)
Applying a short-circuit across the opto-LED of the optocoupler (M5) creates an output overvoltage condition. The output voltage was measured directly at the output connector for both full load (3.34 A) and no-load condition. In no-load condition, the fault condition is processed when the primary controller is active.

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Maximum output voltage in case of OVP 115 V (AC) 25.230 V (AC) 25.6 25.2
Table 8. Condition No-load

Full load (3.34 A)

019aab622
Chan1 (yellow): VO; Chan2 (green): Gate pulse; Chan3 (magenta): Ctrl voltage.

Fig 8.

230 V; 50 Hz; full load maximum output voltage when OVP is triggered

019aab623

Fig 9.
230 V; 50 Hz; no-load maximum output voltage when OVP is triggered

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3.11 Start-up time
Start-up time was measured for three mains input voltages and full load (3.34 A) condition. Vi input measured using a current probe (to avoid adding additional capacitance to the mains input). Vo was measured using a voltage probe grounded at the secondary side.
Table 9. Condition 90 V; 60 Hz 115 V; 60 Hz 230 V; 50 Hz Start-up time Start-up time (s) 3.2 2.0 0.8
If the start-up time is considered too long, it is advised to change the input circuit as described in application note AN10981.

3.12 Start-up profile

The shape of the output voltage was measured for three mains input voltages during start-up directly from the output connector under the full load (3.34 A) condition. Vo was measured using a voltage probe grounded at the secondary side.

019aab624

Fig 10. 90 V; 60 Hz; full load; start up profile

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019aab625
Fig 11. 264 V; 50 Hz; full load; start up profile
Remark: The small discontinuity in the output voltage ramp at 264 V; 50 Hz is caused by the slow start function not limiting the primary current because it is hidden by the leading edge blanking period of 300 ns.

3.13 Hold-up time

Hold-up time is defined as the time between the following moments:
After mains switch off; the moment that the lowest bulk cap voltage during a mains

cycle is crossed

The moment that the output voltage starts to drop
The hold-up time is measured for 115 V; 60 Hz under full load (3.34 A) condition. Output voltage duration was measured directly at the output connector. The hold-up time at 115 V, 60 Hz is 10.9 ms.

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019aab626
Chan1 (yellow): Vo; Chan3 (magenta): Bulk cap voltage.
Fig 12. full load; holdup time at 115 V; 60 Hz

3.14 Dynamic loading

The output voltage was measured at the end of the cable. Both channels of the oscilloscope are set to DC mode.
Table 10. Condition 90 V; 47 Hz Dynamic loading test conditions and results Loading Io: 0 % to 50 %, frequency 50 Hz; duty cycle 50 % Vo(ripple)(p-p) (mV) 375 375
264 V; 63 Hz Io: 0 % to 50 %, frequency 50 Hz; duty cycle 50 %

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Chan1 (yellow): Vo; Chan4 (cyan): Io.
Fig 13. Dynamic loading 90 V; 47 Hz

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Fig 14. Dynamic loading 264 V; 63 Hz

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3.15 Output ripple and noise
Output ripple and noise were measured at the end of the cable using the measurement set-up described in Figure 15. An oscilloscope probe connected to the end of the adapter cable using a probe tip. 100 nF and 1 F capacitors were added between plus and minus to reduce the high frequency noise. Output ripple and noise were measured for mains voltages 90 V; 47 Hz and 264 V; 63 Hz, both at full load (3.34 A) output current.

Adapter cable

100 nF Probe tip

1:10 Probe

014aab151
Fig 15. Output ripple and noise measurement set-up Table 11. Condition 90 V; 47 Hz 264 V; 63 Hz Output ripple and noise measurements Vo(ripple)(p-p) (mV) 130 110

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Chan1 (yellow): Vo; Chan2 (green): Gate pulse
Fig 16. Output ripple and noise at 90 V; 47 Hz

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019aab630
Fig 17. Output ripple and noise at 264 V; 63 Hz

3.16 EMI performance

Conditions:
Type: conducted EMC measurement Frequency range: 150 kHz to 30 MHz Output power: full load condition Supply voltage: 110 V and 230 V (AC) Margin: 6 dB below limit Measurements performed by Cerpass technology corp. Taipei (Taiwan)
Remark: The displayed trace line in the following graphs is the quasi-peak measurement result

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019aab631

019aab632

Fig 18. 115 V, 65 W TEA1738LT/T and TEA1703 demo board phase N
Fig 19. 115 V, 65 W TEA1738LT/T and TEA1703 demo board phase L

019aab633

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Fig 20. 230 V, 65 W TEA1738LT/T and TEA1703 demo board phase N
Fig 21. 230 V, 65 W TEA1738LT/T and TEA1703 demo board phase L

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User manual Rev. February of 27
RD6 V40100C 19.5 V 3.34 A VOUT D5 BAS21 Rk CpF 50 V Rk C17 0.1 F 50 V CpF 50 V Rk CF 25 V CF 25 V R29 4.7 M CpF 100 V 1 Rk Rk T1 FA 2 FB
4. Schematic 65 W TEA1738LT/T and TEA1703 reference board

INLET L

F2 3.15 A 250 V L5
CpF 630 V Rk C1 0.33 F Rk L2 BD1 S2M BD2 S2M

GND BD3 S2M BD4 S2M

CF 400 V

CpF 1 kV

PSENSE

VSENSE

RM RM RM

D1 SA2M

C19 0.1 F 50 V

1 LED M5-B Rk n.c. 2

RRk Rk 2 C21

Rk ZD2 BZX84J-B18 RM

C6 0.22 F 50 V F

D2 1N4148W

M4-A KPS2801B 4 ZD1 BZX84JB24

VISENSE PROTECT 2 1

CnF 50 V F

R31 1.5 M

TEAGND

n.c. 3 Opto

CpF 50 V n.c.

ISENSE DRIVER GND VCC

CpF 50 V R15 4.7 Rk F RC28 0.22 F 50 V Rk Q1 2SK3569

Rk CnF 50 V

1 nF 50 V Rk

CTRL 4 OPTIMER

CnF 50 V

TEA1738T

Q2 PMBT4401

R11 0.2 F

D4 1N4148w F

R17 8.06 k F

M53 KPS2801B

R16 2.2 M F F F

C7 C8 0.1 F 0.22 F 50 V 50 V F F D3 BAV21

D7 BAS21H

D9 1N4148W

M6 AS431I

L3 6.8 H
D Rk G S C22 0.1 F 50 V Rk 019aab243 Q3 2N7002

C11 3.3 F 50 V F

PQ3220
Fig 22. Schematic 65 W TEA1738LT/T and TEA1703 reference board

5. Bill of materials

5.1 Components list
Table 12. Reference R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R26 R27 R28 R29 R30 R31 R32 R33 R34 R35 R36 R37 R38 R39 R40 RT1 C1 C2
Bill of materials Value 910 k; 1 %; 4 W 910 k; 1 %; 4 W 910 k; 1 %; 4 W 910 k; 1 %; 4 W 10 M; 1 %; 4 W 10 M; 1 %; 4 W 10 M; 1 %; 4 W 240 k; 5 %; 8 W 51 k; 1 %; 1 W 51 k; 1 %; 1 W 0.2 ; 1 %; 1 W 33 k; 1 %; 10 W 1 k; 1 %; 1 W 10 ; 5 %; 8 W 4.7 ; 5 %; 8 W 2.2 M; 5 %; 10 W 8.06 k; 5 %; 10 W 39 k; 5 %; 10 W 1 M; 5 %; 10 W 4.7 ; 5 %; 8 W 330 k; 5 %; 10 W 240 k; 5 %; 10 W 4.7 M; 5 %; 10 W 330 k; 5 %; 10 W 1.5 M; 5 %; 10 W 470 ; 5 %; 8 W 1 k; 5 %; 10 W 10 k; 5 %; 10 W 75 k; 5 %; 10 W 11 k; 5 %; 10 W 330 k; 5 %; 10 W 330 k; 5 %; 10 W 10 k; 5 %; 10 W 200 k; 5 % 330 F; 400 V; 105 C 110 F; 400 V; 105 C Description resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; MOF resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip not mounted resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip resistor; thin film chip NTC resistor X2-cap; Arcotronics electric; 20 %, NCC
Package SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 1206 SMD 0805 SMD 1206 SMD 1206 axial lead SMD 0603 SMD 0603 SMD 0603 SMD 0805 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD mm 14.5 mm 8.5 mm 50 mm 11.5 mm

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Table 12. Reference C3 C4 C6 C7 C8 C9 C10 C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 C22 C28 C31 BD1 BD2 BD3 BD4 D1 D2 D3 D4 D5 D6 D7 D8 D9 ZD1 ZD2
Bill of materials continued Value 2200 pF; 630 V 3300 pF; 1 kV 0.22 F; 50 V 0.1 F; 50 V 0.22 F; 50 V 1 nF; 50 V 22 nF; 50 V 3.3 F; 50 V; 105 C 220 pF; 100 V 470 F; 50 V; 105 C 470 F; 50 V; 105 C 56 pF; 50 V 0.1 F; 50 V 220 pF; 50 V 0.1 F; 50 V 10 nF; 50 V 1 nF; 50 V 0.1 nF; 50 V 0.22 nF; 50 V 1000 pF; 400 V (AC) 2 A; 1 kV 2 A; 1 kV 2 A; 1 kV 2 A; 1 kV 2 A; 1 kV 0.15 A; 100 V 0.2 A; 250 V 0.15 A; 100 V 0.2 A; 250 V 40 A; 100 V 0.2 A; 250 V 0.15 A; 100 V 0.15 A; 100 V 24 V 24 V Description MLCC; Z5U MLCC; Z5U 10 %; MLCC; X7R; lead free 10 %; MLCC; X7R 10 %; MLCC; X7R; lead free 10 %; MLCC; X7R 5 %; MLCC; X7R electric, 20 %; KY/NCC not mounted 5 %; MLCC; NPO; KZH/NCC electric, 20 %; KZH/NCC electric, 20 %; KZH/NCC 5 %; MLCC; X7R 10 %; MLCC; X7R 5 %; MLCC; X7R 10 %; MLCC; X7R 10 %; MLCC; X7R 10 %; MLCC; X7R 10 %; MLCC; X7R 10 %; MLCC; X7R; lead free Y1-cap general purpose diode; S2M; trr = 2 S; MCCsemi general purpose diode; S2M; trr = 2 S; MCCsemi general purpose diode; S2M; trr = 2 S; MCCsemi general purpose diode; S2M; trr = 2 S; MCCsemi general purpose diode; S2M; trr = 2 S; MCCsemi switching diode; 1N4148W; trr = 4 nS diode; BAV21W/Vishay; trr = 50 nS switching diode; 1N4148W; trr = 4 nS diode; BAV21W/Vishay; trr = 50 nS Schottky; V40100C; Vishay diode; BAV21H/Vishay; trr = 50 nS; NXP switching diode; 1N4148W; trr = 4 nS switching diode; 1N4148W; trr = 4 nS Zener diode; BZX84J-B24; Vz = 23.5 V to 24.5 V; zt = 5 mA; Ir = 50 nA Zener diode; BZX84J-B18; Vz = 17.6 V to 18.4 V; zt = 5 mA; Ir = 50 nA
Package SMD 1206 SMD 1206 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD mm 11.5 mm SMD 0805 radial lead; 10 mm 12.5 mm radial lead; 10 mm 12.5 mm SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMB SMB SMB SMB SMT SMB SMT SOD123 SMT SOD123 SMT SOD123 SMT SOD123 TO220AB SMT SOD123 SMT SOD123 SMT SOD123 SMT SOD323F SMT SOD323F

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Table 12. Reference ZD3 Q1
Bill of materials continued Value 15 A; 600 V; 0.5 Description not mounted MOSFET; n-channel; 2SK3569/Toshiba; RDSon = 0.5 ; VGS(on) = 3 V; ID = 15 A; Ciss = 1600 pF; VDS = 600 V; VGS = 30 V NPN transistor 80 hFE; VCEO = 40 V; IC = 600 mA MOSFET; n-channel; 2SK3569/Toshiba; RDSon = 5.3 ; VGS(on) = 1 V; ID = 300 mA; Ciss = 40 pF; VDS = 60 V; VGS = 30 V GreenChip SMPS control IC; NXP Semiconductors GreenChip SMPS control IC; NXP Semiconductors optocoupler; CTR = 130 % ~ 260 %; 1-channel; COSMO optocoupler; CTR = 130 % ~ 260 %; 1-channel; COSMO adjustable precision shunt regulator BCD transformer; Np : Ns : Naux = 36 : 6 : 6; JPP44A; A-core N1 : N2 = 52 : 52; JPH10F; A-core choke; 10 %; 275 A; DCR = 1 ; WIS252018N-6R8K; Mingstar choke N1 : N2 = 7 : 7; JPZ10K; A-core fuse; f7use; DIP; MST Package SMT TO220

PMBTA; 600 V; 0.5

SMT TO220 SMT SOT23
M1 M3 M4 M5 M6 T1 L2 L3 L4 L5 F2 LED1 Inlet Cable
TEA1738LT/T TEA1703 KPS2801B KPS2801B AS431l Lp = 400 H choke 6.8 H 10 H choke T3.15 A; 250 V LED 5.0 V; blue inlet cable
SO8 SO8 4-pin SOP 4-pin SOP SMT SOT23 ATQ28/11.2D D = 0.45 mm; 14 mm 59C SMT 2.5 mm 2 mm 1.8 mm DIP D = 0.45 mm; T8 mm 4 mm 49C 8.35 mm 4.3 mm 7.7 mm
M02-0603QBC; Vr = 5 V; IF = 30 mA; Hi-light SMD 0603; 1.6 mm 0.8 mm 0.8 mm 16AWG/1571 2P L = 1200 mm

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6. Transformer specification
6.1 Transformer schematic diagram
2 N3 A N5 NN2, N5, N7 PRIMARY winding start SECONDARY teflon tube copper foil

019aab248

FLYA N1, N6, N9 FLYB
Fig 23. Transformer winding diagram Table 13. Number 9 8c 8b 8a 3c 3b 3a Winding construction Layers secondary primary primary primary Cu foil secondary Cu foil auxiliary primary primary primary Cu foil secondary Turns Wires Copper/diameter Type 0.32 0.35 0.35 0.35 0.35 0.32 0.15 0.35 0.35 0.32 triso enamelled enamelled enamelled triso enamelled enamelled enamelled enamelled triso

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6.2 Winding specification
Table 14. Winding order 9

[1] [2] [3] [4] [5] [6]

Winding table Pin Start FA FA A[4] FA Finish FB 3[6] A 3[6] 3 FB 3[6] 1 FB 0.32 mm 2 mm[1] 0.025 mm 7 mm[2] 0.35 mm 2 mm 0.15 mm 2 mm 0.025 mm 7 mm[2] 0.32 mm 2 mm[1] 0.025 mm 7 mm[2] 0.35 mm 2 mm 0.3 mm 2 mm[1] Wire Turns Layers Turn/ Insulation after Layer winding 6/1 6/tape 1 Ts[3] tape 1 Ts[3] tape 1 Ts[3] tape 1 Ts[3][5] tape 1 Ts[3] tape 1 Ts[3] tape 1 Ts[3] tape 1 Ts[3] tape 1 Ts[3]
N1 S1 N3 N4 S2 N6 S3 N8 N9
Furkukawa. Copper foil. Spread winding. Intermediate connection A is not connected to a pin. Insulation tape 3M #1350 or #1298. Copper foil connected to pin 3 using 0.25 lead wire.
6.3 Electrical characteristics
Table 15. Inductance Electrical characteristics Pin 1 to 2 Specification 700 H 5 % Remark 65 kHz; 1 V Description

6.4 Core and bobbin

Core: ATQ28/11.2D; A-Core, JPP44A

6.5 Marking

Main board: APBADC054

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7. Layout of the 65 W TEA1738LT/T and TEA1703 reference board

019aab245

Fig 24. Copper layout bottom side (top view)

019aab247

Fig 25. Copper layout top side (top view)

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019aab244
Fig 26. Component placement bottom side (bottom view)

019aab246

Fig 27. Component placement top side (top view)

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8. Alternative circuit options
8.1 Changing the output voltage
By changing the following components, the output voltage can be changed (30 %). Refer to the TEA1738(L)T application note for additional information on this topic. Make sure that the Aux voltage remains within its operation limits (12.2 V 30 V typical) and is high enough to start up (20.6 V typical). R23/R24 The resistor divider R36 and R37 determine the output voltage based on Vo = 2.5 V (R36 + R37) / (R37). C13/C14 The voltage rating of these electrolytic capacitors must be chosen to be higher than the output voltage. Decrease the value of the capacitors for applications with a lower output current.

8.2 TEA1703 adjustments

In this design the following items can be improved by changing the value of the inductor L4 to 4m7H. Currently the current through opto LED M4 is too low.
Output power level threshold to enter Standby mode is very low The VCC clamp cannot sink enough current for high mains. This causes the TEA1738
to restart in Standby mode at 264 V; 60 Hz. This behavior is not recommended The minimum output voltage in Standby mode can be adjusted using resistor R30. By increasing resistor R30 from 330 k to 420 k, an additional < 2 mW can be saved and the minimum output voltage will drop to 9 V. Refer to the TEA1703 application note for adjustment information.

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9. Legal information

9.1 Definitions

design. It is customers sole responsibility to determine whether the NXP Semiconductors product is suitable and fit for the customers applications and products planned, as well as for the planned application and use of customers third party customer(s). Customers should provide appropriate design and operating safeguards to minimize the risks associated with their applications and products. NXP Semiconductors does not accept any liability related to any default, damage, costs or problem which is based on any weakness or default in the customers applications or products, or the application or use by customers third party customer(s). Customer is responsible for doing all necessary testing for the customers applications and products using NXP Semiconductors products in order to avoid a default of the applications and the products or of the application or use by customers third party customer(s). NXP does not accept any liability in this respect. Export control This document as well as the item(s) described herein may be subject to export control regulations. Export might require a prior authorization from national authorities. Evaluation products This product is provided on an as is and with all faults basis for evaluation purposes only. NXP Semiconductors, its affiliates and their suppliers expressly disclaim all warranties, whether express, implied or statutory, including but not limited to the implied warranties of non-infringement, merchantability and fitness for a particular purpose. The entire risk as to the quality, or arising out of the use or performance, of this product remains with customer. In no event shall NXP Semiconductors, its affiliates or their suppliers be liable to customer for any special, indirect, consequential, punitive or incidental damages (including without limitation damages for loss of business, business interruption, loss of use, loss of data or information, and the like) arising out the use of or inability to use the product, whether or not based on tort (including negligence), strict liability, breach of contract, breach of warranty or any other theory, even if advised of the possibility of such damages. Notwithstanding any damages that customer might incur for any reason whatsoever (including without limitation, all damages referenced above and all direct or general damages), the entire liability of NXP Semiconductors, its affiliates and their suppliers and customers exclusive remedy for all of the foregoing shall be limited to actual damages incurred by customer based on reasonable reliance up to the greater of the amount actually paid by customer for the product or five dollars (US$5.00). The foregoing limitations, exclusions and disclaimers shall apply to the maximum extent permitted by applicable law, even if any remedy fails of its essential purpose.

Draft The document is a draft version only. The content is still under internal review and subject to formal approval, which may result in modifications or additions. NXP Semiconductors does not give any representations or warranties as to the accuracy or completeness of information included herein and shall have no liability for the consequences of use of such information.

Disclaimers

Limited warranty and liability Information in this document is believed to be accurate and reliable. However, NXP Semiconductors does not give any representations or warranties, expressed or implied, as to the accuracy or completeness of such information and shall have no liability for the consequences of use of such information. In no event shall NXP Semiconductors be liable for any indirect, incidental, punitive, special or consequential damages (including - without limitation - lost profits, lost savings, business interruption, costs related to the removal or replacement of any products or rework charges) whether or not such damages are based on tort (including negligence), warranty, breach of contract or any other legal theory. Notwithstanding any damages that customer might incur for any reason whatsoever, NXP Semiconductors aggregate and cumulative liability towards customer for the products described herein shall be limited in accordance with the Terms and conditions of commercial sale of NXP Semiconductors. Right to make changes NXP Semiconductors reserves the right to make changes to information published in this document, including without limitation specifications and product descriptions, at any time and without notice. This document supersedes and replaces all information supplied prior to the publication hereof. Suitability for use NXP Semiconductors products are not designed, authorized or warranted to be suitable for use in life support, life-critical or safety-critical systems or equipment, nor in applications where failure or malfunction of an NXP Semiconductors product can reasonably be expected to result in personal injury, death or severe property or environmental damage. NXP Semiconductors accepts no liability for inclusion and/or use of NXP Semiconductors products in such equipment or applications and therefore such inclusion and/or use is at the customers own risk. Applications Applications that are described herein for any of these products are for illustrative purposes only. NXP Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing or modification. Customers are responsible for the design and operation of their applications and products using NXP Semiconductors products, and NXP Semiconductors accepts no liability for any assistance with applications or customer product

Trademarks

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26 of 27

10. Contents
1 1.3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.5 5.6.1 6.2 6.3 6.4 6.8 8.1 8.9.1 9.2 9.Introduction. 3 Features. 3 Power supply specification. 4 Performance data. 4 Efficiency. 4 No-load power consumption. 5 Minimum output current in normal operation. 5 Output regulation. 6 Line regulation. 6 Output voltage regulation in Standby mode. 7 OverPower Protection (OPP). 8 VCC voltage. 8 Brownout and start level. 8 OverVoltage Protection (OVP). 8 Start-up time. 10 Start-up profile. 10 Hold-up time. 11 Dynamic loading. 12 Output ripple and noise. 14 EMI performance. 15 Schematic 65 W TEA1738LT/T and TEA1703 reference board. 17 Bill of materials. 18 Components list. 18 Transformer specification. 21 Transformer schematic diagram. 21 Winding specification. 22 Electrical characteristics. 22 Core and bobbin. 22 Marking. 22 Layout of the 65 W TEA1738LT/T and TEA1703 reference board. 23 Alternative circuit options. 25 Changing the output voltage. 25 TEA1703 adjustments. 25 Legal information. 26 Definitions. 26 Disclaimers. 26 Trademarks. 26 Contents. 27
Please be aware that important notices concerning this document and the product(s) described herein, have been included in section Legal information.

NXP B.V. 2011.

All rights reserved.
For more information, please visit: http://www.nxp.com For sales office addresses, please send an email to: salesaddresses@nxp.com Date of release: 28 February 2011 Document identifier: UM10437

Network Working Group Lee Request for Comments: 1738 CERN Category: Standards Track Masinter Corporation

T. Berners-

L. Xerox M.
McCahill University of Minnesota Editors December 1994
Uniform Resource Locators (URL) Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Abstract This document specifies a Uniform Resource Locator (URL), the syntax and semantics of formalized information for location and access of resources via the Internet. 1. Introduction This document describes the syntax and semantics for a compact string representation for a resource available via the Internet. These strings are called "Uniform Resource Locators" (URLs). The specification is derived from concepts introduced by the WorldWide Web global information initiative, whose use of such objects dates from 1990 and is described in "Universal Resource Identifiers in WWW", RFC 1630. The specification of URLs is designed to meet the requirements laid out in "Functional Requirements for Internet Resource Locators" [12]. This document was written by the URI working group of the Internet
Engineering Task Force. or
Comments may be addressed to the editors,
to the URI-WG. Discussions of the group are archived at
Berners-Lee, Masinter & McCahill 1] RFC Uniform Resource Locators (URL)

December

2. General URL Syntax Just as there are many different methods of access to resources, there are several schemes for describing the location of such resources. The generic syntax for URLs provides a framework for new schemes to be established using protocols other than those defined in this document. URLs are used to `locate' resources, by providing an abstract identification of the resource location. Having located a resource, a system may perform a variety of operations on the resource, as might be characterized by such words as `access', `update', `replace', `find attributes'. In general, only the `access' method needs to be specified for any URL scheme. 2.1. The main parts of URLs A full BNF description of the URL syntax is given in Section 5. In general, URLs are written as follows: : A URL contains the name of the scheme being used () followed by a colon and then a string (the ) whose interpretation depends on the scheme. Scheme names consist of a sequence of characters. The lower case letters "a"--"z", digits, and the characters plus ("+"), period ("."), and hyphen ("-") are allowed. For resiliency, programs interpreting URLs should treat upper case letters as equivalent to lower case in scheme names (e.g., allow "HTTP" as well as "http"). 2.2. URL Character Encoding Issues URLs are sequences of characters, i.e., letters, digits, and special
characters. A URLs may be represented in a variety of ways: e.g., ink on paper, or a sequence of octets in a coded character set. The interpretation of a URL depends only on the identity of the characters used. In most URL schemes, the sequences of characters in different parts of a URL are used to represent sequences of octets used in Internet protocols. For example, in the ftp scheme, the host name, directory name and file names are such sequences of octets, represented by parts of the URL. Within those parts, an octet may be represented by
Berners-Lee, Masinter & McCahill 2] RFC Uniform Resource Locators (URL)
the chararacter which has that octet as its code within the USASCII [20] coded character set. In addition, octets may be encoded by a character triplet consisting of the character "%" followed by the two hexadecimal digits (from "0123456789ABCDEF") which forming the hexadecimal value of the octet. (The characters "abcdef" may also be used in hexadecimal encodings.) Octets must be encoded if they have no corresponding graphic character within the US-ASCII coded character set, if the use of the corresponding character is unsafe, or if the corresponding character is reserved for some other interpretation within the particular URL scheme. No corresponding graphic US-ASCII: URLs are written only with the graphic printable characters of the US-ASCII coded character set. The octets 80-FF hexadecimal are not used in US-ASCII, and the octets 00-1F and 7F hexadecimal represent control characters; these must be encoded. Unsafe: Characters can be unsafe for a number of reasons. The space character is unsafe because significant spaces may disappear and insignificant spaces may be introduced when URLs are transcribed or typeset or subjected to the treatment of word-processing programs.

The characters "<" and ">" are unsafe because they are used as the delimiters around URLs in free text; the quote mark (""") is used to delimit URLs in some systems. The character "#" is unsafe and should always be encoded because it is used in World Wide Web and in other systems to delimit a URL from a fragment/anchor identifier that might follow it. The character "%" is unsafe because it is used for encodings of other characters. Other characters are unsafe because gateways and other transport agents are known to sometimes modify such characters. These characters are "{", "}", "|", "\", "^", "~", "[", "]", and "`". All unsafe characters must always be encoded within a URL. For example, the character "#" must be encoded within URLs even in systems that do not normally deal with fragment or anchor identifiers, so that if the URL is copied into another system that does use them, it will not be necessary to change the URL encoding.
Berners-Lee, Masinter & McCahill 3] RFC Uniform Resource Locators (URL)
Reserved: Many URL schemes reserve certain characters for a special meaning: their appearance in the scheme-specific part of the URL has a designated semantics. If the character corresponding to an octet is reserved in a scheme, the octet must be encoded. The characters ";", "/", "?", ":", "@", "=" and "&" are the characters which may be reserved for special meaning within a scheme. No other characters may be reserved within a scheme. Usually a URL has the same interpretation when an octet is represented by a character and when it encoded. However, this is not true for reserved characters: encoding a character reserved for a particular scheme may change the semantics of a URL. Thus, only alphanumerics, the special characters "$-_.+!*'(),", and reserved characters used for their reserved purposes may be used unencoded within a URL.
On the other hand, characters that are not required to be encoded (including alphanumerics) may be encoded within the schemespecific part of a URL, as long as they are not being used for a reserved purpose. 2.3 Hierarchical schemes and relative links In some cases, URLs are used to locate resources that contain pointers to other resources. In some cases, those pointers are represented as relative links where the expression of the location of the second resource is in terms of "in the same place as this one except with the following relative path". Relative links are not described in this document. However, the use of relative links depends on the original URL containing a hierarchical structure against which the relative link is based. Some URL schemes (such as the ftp, http, and file schemes) contain names that can be considered hierarchical; the components of the hierarchy are separated by "/".

label starting and ending with an alphanumerical character and possibly also containing "-" characters. The rightmost domain label will never start with a digit, though, which syntactically distinguishes all domain names from the IP addresses. port The port number to connect to. Most schemes designate protocols that have a default port number. Another port number may optionally be supplied, in decimal, separated from the host by a colon. If the port is omitted, the colon is as well. url-path The rest of the locator consists of data specific to the scheme, and is known as the "url-path". It supplies the details of how the specified resource can be accessed. Note that the "/" between the host (or port) and the url-path is NOT part of the url-path. The url-path syntax depends on the scheme being used, as does the manner in which it is interpreted. 3.2. FTP The FTP URL scheme is used to designate files and directories on Internet hosts accessible using the FTP protocol (RFC959). A FTP URL follow the syntax described in Section 3.1. omitted, the port defaults to 21. If : is
Berners-Lee, Masinter & McCahill 6] RFC Uniform Resource Locators (URL)
3.2.1. FTP Name and Password A user name and password may be supplied; they are used in the ftp "USER" and "PASS" commands after first making the connection to the FTP server. If no user name or password is supplied and one is requested by the FTP server, the conventions for "anonymous" FTP are to be used, as follows: The user name "anonymous" is supplied. The password is supplied as the Internet e-mail address
of the end user accessing the resource. If the URL supplies a user name but no password, and the remote server requests a password, the program interpreting the FTP URL should request one from the user. 3.2.2. FTP url-path The url-path of a FTP URL has the following syntax: //.//;type= Where through and are (possibly encoded) strings and is one of the characters "a", "i", or "d". The part ";type=" may be omitted. The and parts may be empty. The whole url-path may be omitted, including the "/" delimiting it from the prefix containing user, password, host, and port. The url-path is interpreted as a series of FTP commands as follows: Each of the elements is to be supplied, sequentially, as the argument to a CWD (change working directory) command. If the typecode is "d", perform a NLST (name list) command with as the argument, and interpret the results as a file directory listing. Otherwise, perform a TYPE command with and then access the file whose name is the RETR command.) as the argument, (for example, using

Within a name or CWD component, the characters "/" and ";" are reserved and must be encoded. The components are decoded prior to their use in the FTP protocol. In particular, if the appropriate FTP sequence to access a particular file requires supplying a string containing a "/" as an argument to a CWD or RETR command, it is
Berners-Lee, Masinter & McCahill 7] RFC Uniform Resource Locators (URL)
necessary to encode each "/". For example, the URL is interpreted by FTP-ing to "host.dom", logging in as "myname" (prompting for a password if it is asked for), and then executing "CWD /etc" and then "RETR motd". This has a different meaning from which would "CWD etc" and then "RETR motd"; the initial "CWD" might be executed relative to the default directory for "myname". On the other hand, , would "CWD " with a null argument, then "CWD etc", and then "RETR motd".
FTP URLs may also be used for other operations; for example, it is possible to update a file on a remote file server, or infer information about it from the directory listings. The mechanism for doing so is not spelled out here. 3.2.3. FTP Typecode is Optional The entire ;type= part of a FTP URL is optional. If it is omitted, the client program interpreting the URL must guess the appropriate mode to use. In general, the data content type of a file can only be guessed from the name, e.g., from the suffix of the name; the appropriate type code to be used for transfer of the file can then be deduced from the data content of the file. 3.2.4 Hierarchy For some file systems, the "/" used to denote the hierarchical structure of the URL corresponds to the delimiter used to construct a file name hierarchy, and thus, the filename will look similar to the URL path. This does NOT mean that the URL is a Unix filename. 3.2.5. Optimization Clients accessing resources via FTP may employ additional heuristics to optimize the interaction. For some FTP servers, for example, it may be reasonable to keep the control connection open while accessing multiple URLs from the same server. However, there is no common hierarchical model to the FTP protocol, so if a directory change command has been given, it is impossible in general to deduce what sequence should be given to navigate to another directory for a second retrieval, if the paths are different. The only reliable algorithm is to disconnect and reestablish the control connection.

Berners-Lee, Masinter & McCahill 8] RFC Uniform Resource Locators (URL)
3.3. HTTP The HTTP URL scheme is used to designate Internet resources accessible using HTTP (HyperText Transfer Protocol). The HTTP protocol is specified elsewhere. This specification only describes the syntax of HTTP URLs.
An HTTP URL takes the form: http://:/? where and are as described in Section 3.1. If : is omitted, the port defaults to 80. No user name or password is allowed. is an HTTP selector, and is a query string. The is optional, as is the and its preceding "?". If neither nor is present, the "/" may also be omitted. Within the and components, "/", ";", "?" are reserved. The "/" character may be used within HTTP to designate a hierarchical structure. 3.4. GOPHER The Gopher URL scheme is used to designate Internet resources accessible using the Gopher protocol. The base Gopher protocol is described in RFC 1436 and supports items and collections of items (directories). The Gopher+ protocol is a set of upward compatible extensions to the base Gopher protocol and is described in [2]. Gopher+ supports associating arbitrary sets of attributes and alternate data representations with Gopher items. Gopher URLs accommodate both Gopher and Gopher+ items and item attributes. 3.4.1. Gopher URL syntax A Gopher URL takes the form: gopher://:/ where is one of

%09 %09%09

Berners-Lee, Masinter & McCahill 9] RFC Uniform Resource Locators (URL)
If : is omitted, the port defaults to 70. is a single-character field to denote the Gopher type of the resource to which the URL refers. The entire may also be empty, in which case the delimiting "/" is also optional and the defaults to "1". is the Gopher selector string. In the Gopher protocol,
Gopher selector strings are a sequence of octets which may contain any octets except 09 hexadecimal (US-ASCII HT or tab) 0A hexadecimal (US-ASCII character LF), and 0D (US-ASCII character CR). Gopher clients specify which item to retrieve by sending the Gopher selector string to a Gopher server. Within the , no characters are reserved. Note that some Gopher strings begin with a copy of the character, in which case that character will occur twice consecutively. The Gopher selector string may be an empty string; this is how Gopher clients refer to the top-level directory on a Gopher server. 3.4.2 Specifying URLs for Gopher Search Engines If the URL refers to a search to be submitted to a Gopher search engine, the selector is followed by an encoded tab (%09) and the search string. To submit a search to a Gopher search engine, the Gopher client sends the string (after decoding), a tab, and the search string to the Gopher server. 3.4.3 URL syntax for Gopher+ items URLs for Gopher+ items have a second encoded tab (%09) and a Gopher+ string. Note that in this case, the %09 string must be supplied, although the element may be the empty string. The is used to represent information required for retrieval of the Gopher+ item. Gopher+ items may have alternate views, arbitrary sets of attributes, and may have electronic forms associated with them. To retrieve the data associated with a Gopher+ URL, a client will connect to the server and send the Gopher selector, followed by a tab and the search string (which may be empty), followed by a tab and the Gopher+ commands.

Berners-Lee, Masinter & McCahill 10] RFC Uniform Resource Locators (URL)
3.4.4 Default Gopher+ data representation When a Gopher server returns a directory listing to a client, the Gopher+ items are tagged with either a "+" (denoting Gopher+ items)
or a "?" (denoting Gopher+ items which have a +ASK form associated with them). A Gopher URL with a Gopher+ string consisting of only a "+" refers to the default view (data representation) of the item while a Gopher+ string containing only a "?" refer to an item with a Gopher electronic form associated with it. 3.4.5 Gopher+ items with electronic forms Gopher+ items which have a +ASK associated with them (i.e. Gopher+ items tagged with a "?") require the client to fetch the item's +ASK attribute to get the form definition, and then ask the user to fill out the form and return the user's responses along with the selector string to retrieve the item. Gopher+ clients know how to do this but depend on the "?" tag in the Gopher+ item description to know when to handle this case. The "?" is used in the Gopher+ string to be consistent with Gopher+ protocol's use of this symbol. 3.4.6 Gopher+ item attribute collections To refer to the Gopher+ attributes of an item, the Gopher URL's Gopher+ string consists of "!" or "$". "!" refers to the all of a Gopher+ item's attributes. "$" refers to all the item attributes for all items in a Gopher directory. 3.4.7 Referring to specific Gopher+ attributes To refer to specific attributes, the URL's gopher+_string is "!" or "$". For example, to refer to the attribute containing the abstract of an item, the gopher+_string would be "!+ABSTRACT". To refer to several attributes, the gopher+_string consists of the attribute names separated by coded spaces. For example, "!+ABSTRACT%20+SMELL" refers to the +ABSTRACT and +SMELL attributes of an item. 3.4.8 URL syntax for Gopher+ alternate views Gopher+ allows for optional alternate data representations (alternate views) of items. To retrieve a Gopher+ alternate view, a Gopher+ client sends the appropriate view and language identifier (found in the item's +VIEW attribute). To refer to a specific Gopher+ alternate view, the URL's Gopher+ string would be in the form:

Berners-Lee, Masinter & McCahill 11] RFC Uniform Resource Locators (URL)
+%20 For example, a Gopher+ string of "+application/postscript%20Es_ES" refers to the Spanish language postscript alternate view of a Gopher+ item. 3.4.9 URL syntax for Gopher+ electronic forms The gopher+_string for a URL that refers to an item referenced by a Gopher+ electronic form (an ASK block) filled out with specific values is a coded version of what the client sends to the server. The gopher+_string is of the form: +%091%0D%0A+-1%0D%0A%0D%0A%0D%0A.%0D%0A To retrieve this item, the Gopher client sends: +1 +-1
. to the Gopher server. 3.5. MAILTO The mailto URL scheme is used to designate the Internet mailing address of an individual or service. No additional information other than an Internet mailing address is present or implied. A mailto URL takes the form: mailto: where is (the encoding of an) addr-spec, as specified in RFC 822 [6]. Within mailto URLs, there are no reserved characters. Note that the percent sign ("%") is commonly used within RFC 822 addresses and must be encoded. Unlike many URLs, the mailto scheme does not represent a data object to be accessed directly; there is no sense in which it designates an object. It has a different use than the message/external-body type in MIME.
Berners-Lee, Masinter & McCahill 12] RFC Uniform Resource Locators (URL)
3.6. NEWS The news URL scheme is used to refer to either news groups or individual articles of USENET news, as specified in RFC 1036. A news URL takes one of two forms: news: news: A is a period-delimited hierarchical name, such as "comp.infosystems.www.misc". A corresponds to the Message-ID of section 2.1.5 of RFC 1036, without the enclosing "<" and ">"; it takes the form @. A message identifier may be distinguished from a news group name by the presence of the commercial at "@" character. No additional characters are reserved within the components of a news URL. If is "*" (as in ), it is used to refer to "all available news groups". The news URLs are unusual in that by themselves, they do not contain sufficient information to locate a single resource, but, rather, are location-independent. 3.7. NNTP The nntp URL scheme is an alternative method of referencing news articles, useful for specifying news articles from NNTP servers (RFC 977). A nntp URL take the form: nntp://:// where and are as described in Section 3.1. If : is omitted, the port defaults to 119. The is the name of the group, while the article within that newsgroup. is the numeric id of the

The of a WAIS URL consists of the WAIS document-id, encoded as necessary using the method described in Section 2.2. The WAIS document-id should be treated opaquely; it may only be decomposed by the server that issued it. 3.10 FILES The file URL scheme is used to designate files accessible on a particular host computer. This scheme, unlike most other URL schemes, does not designate a resource that is universally accessible over the Internet. A file URL takes the form: file:/// where is the fully qualified domain name of the system on which the is accessible, and is a hierarchical directory path of the form //./. For example, a VMS file DISK$USER:[MY.NOTES]NOTE123456.TXT might become
As a special case, can be the string "localhost" or the empty string; this is interpreted as `the machine from which the URL is being interpreted'. The file URL scheme is unusual in that it does not specify an Internet protocol or access method for such files; as such, its utility in network protocols between hosts is limited. 3.11 PROSPERO The Prospero URL scheme is used to designate resources that are accessed via the Prospero Directory Service. The Prospero protocol is described elsewhere [14].
A prospero URLs takes the form: prospero://:/;= where and are as described in Section 3.1. If : is omitted, the port defaults to 1525. No username or password is
Berners-Lee, Masinter & McCahill 15] RFC Uniform Resource Locators (URL)
allowed. The is the host-specific object name in the Prospero protocol, suitably encoded. This name is opaque and interpreted by the Prospero server. The semicolon ";" is reserved and may not appear without quoting in the. Prospero URLs are interpreted by contacting a Prospero directory server on the specified host and port to determine appropriate access methods for a resource, which might themselves be represented as different URLs. External Prospero links are represented as URLs of the underlying access method and are not represented as Prospero URLs. Note that a slash "/" may appear in the without quoting and no significance may be assumed by the application. Though slashes may indicate hierarchical structure on the server, such structure is not guaranteed. Note that many s begin with a slash, in which case the host or port will be followed by a double slash: the slash from the URL syntax, followed by the initial slash from the. (E.g., designates a of "/pros/name".) In addition, after the , optional fields and values associated with a Prospero link may be specified as part of the URL. When present, each field/value pair is separated from each other and from the rest of the URL by a ";" (semicolon). The name of the field and its value are separated by a "=" (equal sign). If present, these fields serve to identify the target of the URL. For example, the OBJECT-VERSION field can be specified to identify a specific version of an object. 4. REGISTRATION OF NEW SCHEMES A new scheme may be introduced by defining a mapping onto a

6. Security Considerations The URL scheme does not in itself pose a security threat. Users should beware that there is no general guarantee that a URL which at one time points to a given object continues to do so, and does not even at some later time point to a different object due to the movement of objects on servers. A URL-related security threat is that it is sometimes possible to construct a URL such that an attempt to perform a harmless idempotent operation such as the retrieval of the object will in fact cause a possibly damaging remote operation to occur. The unsafe URL is typically constructed by specifying a port number other than that
reserved for the network protocol in question. The client unwittingly contacts a server which is in fact running a different protocol. The content of the URL contains instructions which when interpreted according to this other protocol cause an unexpected operation. An example has been the use of gopher URLs to cause a rude message to be sent via a SMTP server. Caution should be used when using any URL which specifies a port number other than the default for the protocol, especially when it is a number within the reserved space. Care should be taken when URLs contain embedded encoded delimiters for a given protocol (for example, CR and LF characters for telnet protocols) that these are not unencoded before transmission. This would violate the protocol but could be used to simulate an extra operation or parameter, again causing an unexpected and possible harmful remote operation to be performed.
Berners-Lee, Masinter & McCahill 20] RFC Uniform Resource Locators (URL)
The use of URLs containing passwords that should be secret is clearly unwise. 7. Acknowledgements This paper builds on the basic WWW design (RFC 1630) and much discussion of these issues by many people on the network. The discussion was particularly stimulated by articles by Clifford Lynch, Brewster Kahle [10] and Wengyik Yeong [18]. Contributions from John Curran, Clifford Neuman, Ed Vielmetti and later the IETF URL BOF and URI working group were incorporated. Most recently, careful readings and comments by Dan Connolly, Ned Freed, Roy Fielding, Guido van Rossum, Michael Dolan, Bert Bos, John Kunze, Olle Jarnefors, Peter Svanberg and many others have helped refine this RFC.

Berners-Lee, Masinter & McCahill 21] RFC Uniform Resource Locators (URL)
APPENDIX: Recommendations for URLs in Context URIs, including URLs, are intended to be transmitted through protocols which provide a context for their interpretation. In some cases, it will be necessary to distinguish URLs from other possible data structures in a syntactic structure. In this case, is recommended that URLs be preceeded with a prefix consisting of the characters "URL:". For example, this prefix may be used to distinguish URLs from other kinds of URIs. In addition, there are many occasions when URLs are included in other kinds of text; examples include electronic mail, USENET news messages, or printed on paper. In such cases, it is convenient to have a separate syntactic wrapper that delimits the URL and separates it from the rest of the text, and in particular from punctuation marks that might be mistaken for part of the URL. For this purpose, is recommended that angle brackets ("<" and ">"), along with the prefix "URL:", be used to delimit the boundaries of the URL. This wrapper does not form part of the URL and should not be used in contexts in which delimiters are already specified. In the case where a fragment/anchor identifier is associated with a URL (following a "#"), the identifier would be placed within the brackets as well.
In some cases, extra whitespace (spaces, linebreaks, tabs, etc.) may need to be added to break long URLs across lines. should be ignored when extracting the URL. The whitespace
No whitespace should be introduced after a hyphen ("-") character. Because some typesetters and printers may (erroneously) introduce a hyphen at the end of line when breaking a line, the interpreter of a URL containing a line break immediately after a hyphen should ignore all unencoded whitespace around the line break, and should be aware that the hyphen may or may not actually be part of the URL. Examples: Yes, Jim, I found it under Note the warning in. but you can probably pick it up
Berners-Lee, Masinter & McCahill 22] RFC Uniform Resource Locators (URL)

References [1] Anklesaria, F., McCahill, M., Lindner, P., Johnson, D., Torrey, D., and B. Alberti, "The Internet Gopher Protocol (a distributed document search and retrieval protocol)", RFC 1436, University of Minnesota, March 1993.
[2] Anklesaria, F., Lindner, P., McCahill, M., Torrey, D., Johnson, D., and B. Alberti, "Gopher+: Upward compatible enhancements to the Internet Gopher protocol", University of Minnesota, July 1993.
[3] Berners-Lee, T., "Universal Resource Identifiers in WWW: A Unifying Syntax for the Expression of Names and Addresses of Objects on the Network as used in the World-Wide Web", RFC 1630, CERN, June 1994.
[4] Berners-Lee, T., "Hypertext Transfer Protocol (HTTP)", CERN, November 1993.
[5] Braden, R., Editor, "Requirements for Internet Hosts -Application and Support", STD 3, RFC 1123, IETF, October 1989.
[6] Crocker, D. "Standard for the Format of ARPA Internet Text Messages", STD 11, RFC 822, UDEL, April 1982.
[7] Davis, F., Kahle, B., Morris, H., Salem, J., Shen, T., Wang, R., Sui, J., and M. Grinbaum, "WAIS Interface Protocol Prototype Functional Specification", (v1.5), Thinking Machines Corporation, April 1990.
[8] Horton, M. and R. Adams, "Standard For Interchange of USENET Messages", RFC 1036, AT&T Bell Laboratories, Center for Seismic Studies, December 1987.
[9] Huitema, C., "Naming: Strategies and Techniques", Computer Networks and ISDN Systems 23 (1991) 107-110.
Berners-Lee, Masinter & McCahill 23] RFC Uniform Resource Locators (URL)
[10] Kahle, B., "Document Identifiers, or International Standard Book Numbers for the Electronic Age", 1991.
[11] Kantor, B. and P. Lapsley, "Network News Transfer Protocol: A Proposed Standard for the Stream-Based Transmission of News", RFC 977, UC San Diego & UC Berkeley, February 1986.
[12] Kunze, J., "Functional Requirements for Internet Resource Locators", Work in Progress, December 1994.
[13] Mockapetris, P., "Domain Names - Concepts and Facilities", STD 13, RFC 1034, USC/Information Sciences Institute, November 1987.
[14] Neuman, B., and S. Augart, "The Prospero Protocol", USC/Information Sciences Institute, June 1993.
[15] Postel, J. and J. Reynolds, "File Transfer Protocol (FTP)", STD 9, RFC 959, USC/Information Sciences Institute, October 1985.
[16] Sollins, K. and L. Masinter, "Functional Requirements for Uniform Resource Names", RFC 1737, MIT/LCS, Xerox Corporation, December 1994.
[17] St. Pierre, M, Fullton, J., Gamiel, K., Goldman, J., Kahle, B., Kunze, J., Morris, H., and F. Schiettecatte, "WAIS over Z39.50-1988", RFC 1625, WAIS, Inc., CNIDR, Thinking Machines Corp., UC Berkeley, FS Consulting, June 1994.
[18] Yeong, W. "Towards Networked Information Retrieval", Technical report 91-06-25-01, Performance Systems International, Inc. , June 1991. [19] Yeong, W., "Representing Public Archives in the Directory", Work in Progress, November 1991.

Berners-Lee, Masinter & McCahill 24] RFC Uniform Resource Locators (URL)
[20] "Coded Character Set -- 7-bit American Standard Code for Information Interchange", ANSI X3.4-1986. Editors' Addresses Tim Berners-Lee World-Wide Web project CERN, 1211 Geneva 23, Switzerland Phone: +41 (22)Fax: +41 (22)EMail: timbl@info.cern.ch
Larry Masinter Xerox PARC 3333 Coyote Hill Road Palo Alto, CA 94034 Phone: (415) 812-4365 Fax: (415) 812-4333 EMail: masinter@parc.xerox.com
Mark McCahill Computer and Information Services, University of Minnesota Room 152 Shepherd Labs 100 Union Street SE
Minneapolis, MN 55455 Phone: (612) EMail: mpm@boombox.micro.umn.edu
Berners-Lee, Masinter & McCahill 25]