High Performance Synchronous Buck Controller with DCR Current Sensing

The LM27402 is a synchronous voltage mode DC/DC buck controller with inductor DCR current sense capability. Sensing the inductor current eliminates the need to add resistive powertrain elements which increases overall efficiency and facilitates accurate continuous current limit sensing. A 0.6V ±1% voltage reference enables high accuracy and low voltage capability at the output. An input operating voltage range of 3V to 20V makes the LM27402 suitable for a large variety of input rails. The LM27402 voltage mode control loop incorporates input voltage feed-forward to maintain stability throughout the entire input voltage range. The switching frequency is adjustable from 200 kHz to 1.2 MHz. Dual high current integrated N-channel MOSFET drivers support large Q G , low R DS(ON) MOSFETs. A power good indicator provides power rail se-quencing capability and output fault detection. Adjustable external soft-start capability limits inrush current and provides monotonic output control during startup. Other features include external tracking of other power supplies, integrated LDO bias supply, and synchronization capability. The LM27402 is offered in a 16 pin eTSSOP package and a 4 mm x 4 mm 16 pin exposed LLP.