The NTE1721 and NTE1723 are pulse width modulator controlcircuits designed to offer improved performance and lowered external parts count when implemented for controlling all types of switching power supplies. The nochip +5.1V reference is trimmed to 1% and the input commonmode range of the errror amplifier 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 dead time can be programmed by a single resistor connected between the CT and the Discharge pins. These devices also feature a builtin softstart circuitry, requiring only an external timing capacitor. A shutdown pin controls both the soft start circuitry and the output stages, provided instantaneous turnoff through the PWM latch with pulsed shutdown, as well as softstart recycle with longer shutdown commands. The under voltage lockout inhibits the outputs and the changing of the softstart capacitor when VCC is below nominal. The output stages are totempole design capable of sinking and sourcing in excess of 200mA. The output stages of the NTE1721 features NOR logic resulting in a low output for an off state while the NTE1723 utilizes OR logic which gives a high output when off. Features: