1 Features

• Wide input range from 3.5 V to 78 V (80-V

absolute maximum)

– Minimum 2.8 V when V(BIAS) > 3.5 V

• Output voltage from 3.3 V to 78 V

• Low shutdown IQ of 3 μA

• Low operating IQ of 60 μA

• 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

• 2-A peak current logic level gate driver

– Integrated bootstrap diode

– Bootstrap overvoltage and undervoltage

protection

• Fixed frequency independent from operating mode

(boost, buck-boost, buck)

– Forced PWM mode selectable

– Switching up to 2 MHz for small solution and

component size

– External clock synchronization

• Spread spectrum operation selectable

• Adjustable undervoltage and overvoltage

protection

• Hiccup overcurrent protection

2 Applications

• Non-isolated DC/DC supply (merchant DC/DC,

remote radio unit, motor drive control)

• Backup power systems (battery backup, fire

safety)

• Industrial PC (single board computer)

• Medical PSU (oxygen concentrator)

• Power over ethernet (router)

• Solar power (solar charge controller)

3 Description

The LM5177 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 safe mode, the

device supports superb efficiency over the full rage

of the output current. The LM5177 runs at a fixed

switching frequency, which can be 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

can help monitor and limit input and output current

of the LM5177. This feature also supports charging

backup power elements, like batteries or capacitors,

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