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

130
A Start-up Current

750
A Operating Current

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 starting,

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 occurred.

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.