U3525

The UTC U3525 is a pulse width modulator IC and designed for switching power supplies application to improve performance and reduce external parts usage.

A shutdown terminal controls U3525 both the soft-start circuitry and the output stages, providing instantaneous turn off through the PWM latch with pulsed shutdown, as well as soft-start recycle with longer shutdown commands. The output stage U3525 features NOR logic, giving a LOW output for an OFF state. An under-voltage lockout circuitry, which keeps the outputs off and the soft-start capacitor discharged for sub-normal input voltages, includes approximately 500 mV of hysteresis for jitter free operation. The PWM circuits of U3525 also feature a latch following the comparator. When a PWM pulses has been terminated, the outputs will remain off for the duration of the period. The latch of U3525 is reset with each clock pulse. The output stages are totem-pole designs capable of sourcing or sinking in excess of 200mA.