The UCC28C4x-Q1 family devices are high performance current-mode PWM controllers. The UCC28C4x-Q1 family supports a fixed-frequency, peak current-mode flyback implementation with UVLO and maximum duty-cycle limit options. UCC28C4X-Q1 can be configured with either primary-side regulation using an auxiliary winding or secondary-side regulation with the use of an opto-coupler. This family of devices features high frequency operation up to 1 MHz with low start up and operating currents, thus minimizing start up loss and operating power consumption for improved efficiency. The devices also feature a fast current sense to output delay time of 35 ns, and a ±1-A peak output current capability for driving large external MOSFETs directly. The UCC28C4x-Q1 family is offered in the 8-pin SOIC (D) package.