The TPS6735 is a fixed negative 5-V output inverting dc/dc converter capable of delivering 200 mA from inputs as low as 4.5 V. The only external components required are an inductor, an output filter capacitor, an input filter capacitor, a reference filter capacitor, and a Schottky rectifier. An enable input is provided to shut down the inverter when a 5-V output is not needed. The typical supply current is 1.9 mA at no-load and is further reduced to 1-A when the enable input is low. The TPS6735 is a 160-kHz current-mode pulse-width-modulation (PWM) controller with a p-channel MOSFET power switch. The gate drive uses the 5-V output to reduce the die area needed to realize the 0.4- MOSFET. Soft start is accomplished with the addition of one small capacitor at SS. A 1.22-V reference is available for external loads up to 125 A.