onsemi | SG3525ANG

The SG3525A pulse width modulator control circuit offers improved performance and lower external parts count when implemented for controlling all types of switching power supplies.

The on-chip +5.1 V reference is trimmed to +/-1% and the error amplifier has an input common-mode voltage range that includes the reference voltage, thus eliminating the need for external divider resistors. A sync input to the oscillator enables multiple units to be slaved or a single unit to be synchronized to an external system clock. A wide range of deadtime can be programmed by a single resistor connected between the CT and Discharge pins. This device also features built-in soft-start circuitry, requiring only an external timing capacitor. A shutdown pin controls 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 under voltage lockout inhibits the outputs and the changing of the soft-start capacitor when VCC is below nominal. The output stages are totem-pole design capable of sinking and sourcing in excess of 200 mA. The output stage of the SG3525A features NOR logic resulting in a low output for an off-state.
 
Key Features:

• 8.0 V to 35 V Operation
• 5.1 V +/- 1.0% Trimmed Reference
• 100 Hz to 400 kHz Oscillator Range
• Separate Oscillator Sync Pin
• Adjustable Deadtime Control
• Input Undervoltage Lockout
• Latching PWM to Prevent Multiple Pulses
• Pulse-by-Pulse Shutdown
• Dual Source/Sink Outputs: +/- 400 mA Peak
• Pb-Free Packages are Available

Applications:

• Half Bridge
• Push-Pull