UCC35702

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
• 130A Start-up Current
• 750A Operating Current


Pinout




Specifications

Supply voltage (Supply current limited to 20mA) . . . . . . . . 15V
Supply Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20mA
Input pins ( ILIM,VFF,RT,CT,VSCLAMP,SYNC,SS) . . . . . . 6V
Output Current (OUT) DC. . . . . . . . . . . . . . . . . . . . . +/180mA
Output Current (OUT) Pulse (0.5ms) . . . . . . . . . . . . . . +/1.2A
Storage Temperature. . . . . . . . . . . . . . . . . . . 65 to +150
Junction Temperature. . . . . . . . . . . . . . . . . . . 55 to +150
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . +300
Note: All voltages are with respect to GND. Currents are positive into the specified terminal. Consult Packaging Section of the Databook for thermal limitations and considerations of packages.


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.