1 Features

• Wide input range from 3.5V to 80V (85V absolute

maximum)

– Minimum 2.8V when V(BIAS) > 3.5V

• Output voltage from 3.3V to 78V

• Low shutdown IQ of 3μA

• Low operating IQ of 60μA

• 3% reverse current limit accuracy for precise

charging currents

• Average input and output current monitor or limiter

• Dynamic output voltage tracking for PWM or

analog input signals

• Power save mode (PSM) selectable for high light

load efficiency

• Two integrated high-voltage supply LDOs with

automatic selection

• 2A peak current logic level gate driver with

integrated bootstrap diode and bootstrap voltage

protections

• Fixed frequency across all operating modes

(boost, buck-boost, buck)

– Forced PWM mode selectable

– Switching up to 2MHz for small solution and

component size

– External clock synchronization

• Spread spectrum operation selectable

• Adjustable undervoltage protection

• Hiccup overcurrent and short protection

• AEC-Q100 qualified for automotive applications

– Test temperature grade 1: –40°C to +150°C

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

2 Applications

• Automotive head unit

• Unboosted audio amplifier with ANC

• Headlight

• ADAS domain controller

3 Description

The LM51770-Q1 is a four switch buck-boost

controller. The device provides a regulated output

voltage if the input voltage is higher, equal, or lower

than the adjusted output voltage. In power save

mode, the device supports high efficiency with low

output loads due to its low quiescence currents. In

power save mode, the device supports high efficiency

close to 99% efficiency over the full range of the

output current. The LM51770-Q1 runs at a fixed

switching frequency, which is set through the RT

or SYNC pin. The switching frequency remains the

same during buck, boost, and buck-boost operation.

The integrated and optional average current monitor

helps monitor and limit input and output current of

the LM51770-Q1. This feature also supports charging

backup power elements, like batteries or capacitors,

with constant current (CC) and constant voltage (CV).