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UCC15701/2

UCC25701/2

UCC35701/2

Advanced Voltage Mode Pulse Width Modulator

DESCRIPTION

The UCC35701/UCC35702 family of pulse width modulators is intended for

isolated switching power supplies using primary side control. They can be

used for both off-line applications and DC/DC converter designs such as in

a distributed power system architecture or as a telecom power source.

The devices feature low startup current, allowing for efficient off-line start

ing, yet have sufficient output drive to switch power MOSFETs in excess of

500kHz.

Voltage feed forward compensation is operational over a 5:1 input range

and provides fast and accurate response to input voltage changes over a

4:1 range. An accurate volt-second clamp and maximum duty cycle limit

are also featured.

Fault protection is provided by pulse by pulse current limiting as well as the

ability to latch off after a programmable number of repetitive faults has oc

curred.

Two UVLO options are offered. UCC35701 family has turn-on and turn-off

thresholds of 13V/9V and UCC35702 family has thresholds of 9.6V/8.8V.

The UCC35701/2 and the UCC25701/2 are offered in the 14 pin SOIC (D),

14 pin PDIP (N) or in 14 pin TSSOP (PW) packages. The UCC15701/2 is

offered in the 14 pin CDIP (J) package.

3VDD

12 VREF

8FB

4OUT

2ILIM

5PGND

1 COUNT

14 S S

11 S YNC

9VSCLAMP

VREF

10 CT

7RT

VFF

13GND

SUPPLY

RETURN

RGND

R10

RCS

OUT

UCC35701

R12

R11

R13

R14

OUT

R15

TYPICAL APPLICATION DIAGRAM

SLUS293C - JANUARY 2000 - REVISED JUNE 2005

FEATURES

700kHz Operation

Integrated Oscillator/ Voltage Feed

Forward Compensation

Accurate Duty Cycle Limit

Accurate Volt-second Clamp

Optocoupler Interface

Fault Counting Shutdown

Fault Latch off or Automatic Shutdown

Soft Stop Optimized for Synchronous

Rectification

1A Peak Gate Drive Output

130mA Start-up Current

750mA Operating Current

UDG-98005-1

application

INFO

available

Summary of content (24 pages)

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application INFO available UCC15701/2 UCC25701/2 UCC35701/2 Advanced Voltage Mode Pulse Width Modulator FEATURES DESCRIPTION 700kHz Operation The UCC35701/UCC35702 family of pulse width modulators is intended for isolated switching power supplies using primary side control. They can be used for both off-line applications and DC/DC converter designs such as in a distributed power system architecture or as a telecom power source.
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UCC15701/2 UCC25701/2 UCC35701/2 ORDERING INFORMATION ABSOLUTE MAXIMUM RATINGS Supply voltage (Supply current limited to 20mA) . . . . . . . . 15V Supply Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20mA Input pins ( ILIM,VFF,RT,CT,VSCLAMP,SYNC,SS, FB) . . . 6V Output Current (OUT) DC. . . . . . . . . . . . . . . . . . . . . +/–180mA Output Current (OUT) Pulse (0.5ms) . . . . . . . . . . . . . . +/–1.2A Storage Temperature. . . . . . . . . . . . . . . . . . .
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UCC15701/2 UCC25701/2 UCC35701/2 ELECTRICAL CHARACTERISTICS:Unless otherwise specified, VDD = 11V, RT = 60.4k, CT = 330pF, CREF = CVDD = 0.1m F, VFF = 2.0V, and no load on the outputs. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Line Sense Vth High Line Comparator 3.9 4 4.1 V Vth Low Line Comparator 0.5 0.6 0.7 V Input Bias Current –100 100 nA Oscillator Section 90 100 110 kHz Frequency VFF = 0.8V to 3.2V 90 100 110 kHz Frequency VFF = 0.6V to 3.4V (Note 1) SYNC VIH 2 V SYNC VIL 0.
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UCC15701/2 UCC25701/2 UCC35701/2 DETAILED BLOCK DIAGRAM 2*IRT 11 S VFF 6 RT 7 CT 10 Q IRT 3 VDD 4 OUT 5 P GND P WM 0.2V S + VALLEY 8 1.5R VS CLAMP RD P EAK 0.7V FB S YNC 3m A Q RD R 9 4V HIGH LINE VREF I SS 0.6V 4.5V 14 S S DONE 0.6V ILIM 2 25*I CURRENT FAULT 0.2V CURRENT LIMIT VREF 0.2V D P WM S S DONE COUNT 13/9V (35701) 9.6/8.8V (35702) RUN LOW LINE 1 Q R Q VDD SD I R R Q SD 4V FAULT LATCH 5.
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UCC15701/2 UCC25701/2 UCC35701/2 PIN DESCRIPTIONS (cont.) VSCLAMP: Voltage at this pin is compared to the CT voltage, providing a constant volt-second limit. The comparator output terminates the PWM pulse when the ramp voltage exceeds VSCLAMP. The maximum on time is given by: source. While the soft start capacitor is charging, and while VSS < (0.4 VFB), the duty cycle, and therefore the output voltage of the converter is determined by the soft start circuitry.
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UCC15701/2 UCC25701/2 UCC35701/2 APPLICATION INFORMATION (cont.) Output Inhibit VFF is intended to operate accurately over a 4:1 range between 0.8V and 3.2V. Voltages at VFF below 0.6V or above 4.0V will initiate a soft stop cycle and a chip restart when the under/over voltage condition is removed. During normal operation, OUT is driven high at the start of a clock period and is driven low by voltages on CT, FB or VSCLAMP.
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UCC15701/2 UCC25701/2 UCC35701/2 APPLICATION INFORMATION (cont.) UCC35701/2 is pin to pin compatible to UCC3570 but is not a direct drop-in replacement for UCC3570 sockets. The changes required to the power supply printed circuit board of for existing UCC3570 designs are minimal. For conversion, only one extra resistor to set the volt-second clamp needs to be added to the existing PC board layouts.
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UCC15701/2 UCC25701/2 UCC35701/2 TYPICAL WAVEFORMS (cont.) VFF CT S YNC UDG-98208 Figure 2. Timing diagram for oscillator waveforms showing feedforward action and synchronization. TYPICAL CHARACTERISTIC CURVES 1.03 1000 100 NORMALIZED DUTY CYCLE FREQUENCY [kHz] VFF=3.2 100pF 150pF 220pF 330pF 470pF 10 20 60 100 140 RT [K ] 180 NORMALIZED FREQUENCY 1 0.99 VFF=3.2 0.98 5 25 45 0.98 -35 -15 5 25 45 65 85 Figure 5. Normalized maximum duty cycle vs. temperature. VFF=0.8 -15 0.
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UCC15701/2 UCC25701/2 UCC35701/2 APPLICATION INFORMATION (cont.
PAGE 10
UCC15701/2 UCC25701/2 UCC35701/2 REVISION HISTORY DATE 02/16/05 6/16/05 REVISION SLUS293B SLUS293C REASON Add FB to abs max table. Created revision history table. Updated block diagram and the SS pin description.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com Orderable Device 11-Apr-2013 Status (1) UCC35702PWG4 ACTIVE Package Type Package Pins Package Drawing Qty TSSOP PW 14 90 Eco Plan Lead/Ball Finish (2) Green (RoHS & no Sb/Br) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) CU NIPDAU Level-2-260C-1 YEAR (4) 0 to 70 35702 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant UCC25701DTR SOIC D 14 2500 330.0 16.4 6.5 9.0 2.1 8.0 16.0 Q1 UCC25701PWTR TSSOP PW 14 2000 330.0 12.4 6.9 5.6 1.6 8.0 12.0 Q1 UCC25702DTR SOIC D 14 2500 330.0 16.4 6.5 9.0 2.1 8.0 16.
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PACKAGE MATERIALS INFORMATION www.ti.com 26-Jan-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) UCC25701DTR SOIC D 14 2500 333.2 345.9 28.6 UCC25701PWTR TSSOP PW 14 2000 367.0 367.0 35.0 UCC25702DTR SOIC D 14 2500 333.2 345.9 28.6 UCC25702PWTR TSSOP PW 14 2000 367.0 367.0 35.0 UCC35701DTR SOIC D 14 2500 333.2 345.9 28.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.