UCC35705

Features:

`Greater Than 4-MHz Operation
` Integrated Oscillator / Voltage Feed Forward Compensation
`>4:1 Input Voltage Range
` 25-ns Current Limit Delay
` Programmable Maximum Duty Cycle Clamp
` Optocoupler Interface
`50-A Start-Up Current
`4.2-mA Operating Current @ 1 MHz
`Smallest Footprint of the 8-pin MSOP Package Minimizes Board Area and Height


Pinout




Specifications

Supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 V
Input voltage (VFF,RC,ILIM) . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Input voltage (FB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 V
Input current (DISCH) . . . . . . . . . . . . . . . . . . . . . . . . .  .. . . 1 mA
Output current (OUT) dc . . . . . . . . . . . . . . . . . . . . . .. . . ±20 mA
Storage temperature, T_stg . . . . . . . . . . . . . . . . .  65 to 150
Junction temperature, T_J . . . . . . . . . . . . .  . . . . . 55 to 150
Lead temperature (soldering, 10 sec.) . . . . . . . . . . . . . . .. 300


Description

The UCC35705 and UCC35706 devices are 8-pin voltage mode primary side controllers with fast over-current protection. These devices are used as core high-speed building blocks in high performance isolated and non-isolated power converters.

UCC35705/UCC35706 devices feature a high speed oscillator with integrated feed-forward compensation for improved converter performance. A typical current sense to output delay time of 25 ns provides fast response to overload conditions. The IC also provides an accurate programmable maximum duty cycle clamp for increased protection which can also be disabled for the oscillator to run at maximum possible duty cycle.

Two UVLO options are offered. The UCC35705 with lower turn-on voltage is intended for dc-to-dc converters while the higher turn-on voltage and the wider UVLO range of the UCC35706 is better suited for offline applications.

The UCC35705/UCC35706 family is offered in 8-pin MSOP (DGK), SOIC (D) and PDIP (P) packages.