DESCRIPTION

· The UCC3809 family is a BCDMOS economy low power IC designed for off-line and isolated DC-to-DC fixed frequency current mode switching power supplies.
· It includes undervoltage lockout, a user-accessible voltage reference, PWM comparator, and totem pole output stage for driving N-Channel MOSFETs.
· Oscillator frequency and maximum duty cycle are programmable with resistors and a capacitor.
· Available in 8-pin SOIC, PDIP, TSSOP, and MSOP packages.

FEATURES

· User programmable soft start with active low shutdown.
· User programmable maximum duty cycle.
· Accessible 5V reference.
· Undervoltage lockout.
· Operation up to 1MHz.
· 0.4A source/0.8A sink FET driver.
· Low 100µA startup current.

APPLICATIONS

· Off-line and isolated DC-to-DC fixed frequency current mode switching power supplies.
· Applications requiring minimal external parts count.
· Systems where board space and height are critical.