Description

The LM51231-Q1 device is a wide input range synchronous boost controller that employs peak current mode control. 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 output voltage can be dynamically programmed by using the tracking function. Bypass mode operation is automatically entered when VSUPPLY > VLOAD, eliminating the body diode drop of the high-side MOSFET. 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 a small solution size and fast transient response.

The device has built-in protection features such as peak current limit, which is constant over VSUPPLY, overvoltage protection, and thermal shutdown. External clock synchronization, programmable spread spectrum modulation, and a lead-less package with minimal parasitic, help to 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.

Features:

AEC-Q100 qualified for automotive applications

Temperature grade 1: –40°C to +125°C, TA

Functional Safety-Capable

Documentation available to aid functional safety system design

Suited for wide operating range automotive battery powered applications

3.8-V to 42-V input operating range

Dynamically programmable VOUT from 5 V to 20 V, or from 15 V to 57 V

Minimum boost input 0.8 V when BIAS ≥ 3.8 V

Bypass operation when VSUPPLY > VLOAD

BIAS shutdown current ≤ 3 µA

Small solution size

Maximum switching frequency 2.2 MHz

Internal boot diode

QFN-20 with wettable flanks

EMI mitigation and avoid AM band interference and crosstalk

Optional clock synchronization

Switching frequency from 100 kHz to 2.2 MHz

Selectable switching mode (FPWM, diode emulation)

Optional programmable spread spectrum

Lead-less package

Programmability and flexibility

Dynamic VOUT tracking

Dynamic switching frequency programming

Supports DCR inductor current sensing

Programmable input voltage UVLO

Adjustable soft start

Adaptive dead-time

PGOOD indicator

Integrated protection features

Constant cycle-by-cycle peak current limit over VSUPPLY

Overvoltage protection

HB-SW short protection

Thermal shutdown