The LM51231-Q1 device is a wide input range synchronous boost controller that employs peak current mode control. The output voltage can be dynamically programmed by using the tracking function on the TRK pin. Bypass mode operation is automatically entered when the supply voltage is greater than the boost output regulation target. Bypass mode eliminates the need for an external bypass switch, by driving the high-side MOSFET at 100% duty cycle, decreasing the power dissipation by eliminating the high-side body diode voltage drop.

The device's wide input range supports automotive cold-crank and load dump. The minimum input voltage can be as low as 0.8 V when BIAS is equal to or greater than 3.8 V. The switching frequency is dynamically programmed with an external resistor from 100 kHz to 2.2 MHz. Switching at 2.2 MHz minimizes AM band interference and allows for a small solution size and fast transient response. Controller architecture simplifies thermal management at harsh ambient temperature conditions when compared to converter architectures.

The device has built-in protection features such as peak current limit, which is constant over input voltage, overvoltage protection, and thermal shutdown. External clock synchronization, programmable spread spectrum modulation, and a lead-less package with minimal parasitic, help reduce EMI and avoid cross talk. Additional features include line UVLO, FPWM, diode emulation, DCR inductor current sensing, programmable soft start, and a power-good indicator.