The SG3525A PWM controller provides higher performance with less external parts count and can be 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 voltage range that includes the reference voltage, eliminating the need for external divider resistors. An oscillator sync input allows multiple devices to be slaved or to synchronize a device to an external system clock. A wider dead time range can be achieved by connecting a resistor between CT and the discharge pin. The device also has built-in soft-start circuitry, requiring only an external timing capacitor. A shutdown pin controls both the soft-start circuit and the output stage, providing instantaneous shutdown via a PW latch with pulsed shutdown and soft-start recirculation with a longer shutdown command. When VCC is below nominal, the undervoltage lockout will inhibit the output and replacement of the soft-start capacitor. The output stage is a totem pole design capable of sinking and sourcing over 200 mA. The output stage of the SG3525A has NOR logic to generate a low output for the off state.
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