The TPS43000 is a high-frequency, voltage-mode, synchronous PWM controller that can be used in buck, boost, SEPIC, or flyback topologies. This highly flexible, full-featured controller is designed to drive a pair of external MOSFETs (one N-channel and one P-channel), enabling it for use with a wide range of output voltages and power levels. With an automatic PFM mode, a shutdown current of less than 1 A, a sleep-mode current of less than 100 A and a full operating current of less than 2 mA at 1 MHz, it is ideal for building highly efficient, dc-to-dc converters. The TPS43000 operates over a wide input voltage range of 1.8 V to 9.0 V. Typical power sources are distributed power systems, two to four nickel or alkaline batteries, or one to two lithium-ion cells. It can be used to generate regulated output voltages from as low as 0.8 V to 8 V or higher. It operates either in a fixed-frequency mode, where the user programs the frequency (up to 2 MHz), or in an automatic PFM mode. In the automatic mode, the controller goes to sleep when the inductor current goes discontinuous, and wakes up when the output voltage has fallen by 2%. In this hysteretic mode of operation, very high efficiency can be maintained over a very wide range of load current. The device can also be synchronized to an external clock source using the dual function SYNC/SD input pin.