The UC1525A/1527A series of pulse width modulator integrated circuits are designed tooffer improved performance and lowered external parts count when used in designing all types ofswitching power supplies. The on-chip 5.1-V reference is trimmed to 1% and the input common-moderange of the error amplifier includes the reference voltage, eliminating external resistors. A syncinput to the oscillator allows multiple units to be slaved or a single unit to be synchronized toan external system clock. A single resistor between CT and the dischargeterminals provides a wide range of dead-time adjustment. These devices also feature built-insoft-start circuitry with only an external timing capacitor required. A shutdown terminal controlsboth the soft-start circuitry and the output stages, providing instantaneous turn off through thePWM latch with pulsed shutdown, as well as soft-start recycle with longer shutdown commands.
Feature
- 8-V to 35-V Operation
- 5.1-V Reference Trimmed to 1%
- 100-Hz to 500-kHz Oscillator Range
- Separate Oscillator Sync Terminal
- Adjustable Dead-Time Control
- Internal Soft Start
- Pulse-by-Pulse Shutdown
- Input Undervoltage Lockout With Hysteresis
- Latching PWM to Prevent Multiple Pulses
- Dual Source and Sink Output Drivers
