IMP38C4x

The IMP38C4x and IMP38HC4x are fixed frequency, high performance, current-mode PWM controllers that are pin compatible with bipolar 384x devices but feature improvements resulting from IMP's BiCMOS processing and circuit design. Notable among the improvements of IMP38C4x are zero cross-conduction/shoot-through current, reduced start-up and operating current, lower current-sense delay, higher frequency operation, full supply voltage swing at the output and a 1% trimmed voltage reference.

IMP38C4x and IMP38HC4x output driver stage has zero cross-conduction current. A proprietary output state-machine monitors each output MOSFET and guarantees by design zero cross-conduction current. This is an industry first for 384x PWM devices.

Under-voltage lockout (UVL) performance has been improved. When the power supply voltage of IMP38C4x is below the startup voltage, internal circuitry puts the output into a low impedance state. The output will sink 20mA and remain below 1.3V, well below the turn-on threshold voltage of the external MOSFET IMP38C4x. Even when VDD drops to zero volts, the out pin will not rise above approximately 1.3V because the output UVLO circuit is