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).