1 Features

1• Ultra-Wide Input Voltage Range From 3 V to 75 V

• Emulated Peak Current Mode Control

• Smooth Transition Between Step-Down and Step-

Up Modes

• Switching Frequency Programmable to 500 KHz

• Oscillator Synchronization Capability

• Internal High Voltage Bias Regulator

• Integrated High and Low-Side Gate Drivers

• Programmable Soft-Start Time

• Ultra-Low Shutdown Current

• Enable Input Wide Bandwidth Error Amplifier

• 1.5% Feedback Reference Accuracy

• Thermal Shutdown

• Package: 20-Pin HTSSOP (Exposed Pad)

• Create a Custom Design Using the LM5118 With

the WEBENCH® Power Designer

2 Applications

Industrial Buck-Boost Supplies

3 Description

The LM5118 wide voltage range Buck-Boost

switching regulator controller features all of the

functions necessary to implement a highperformance,

cost-efficient Buck-Boost regulator

using a minimum of external components. The Buck-

Boost topology maintains output voltage regulation

when the input voltage is either less than or greater

than the output voltage, making it especially suitable

for automotive applications. The LM5118 operates as

a buck regulator while the input voltage is sufficiently

greater than the regulated output voltage and

gradually transitions to the buck-boost mode as the

input voltage approaches the output. This dual-mode

approach maintains regulation over a wide range of

input voltages with optimal conversion efficiency in

the buck mode and a glitch-free output during mode

transitions. This easy-to-use controller includes

drivers for the high-side buck MOSFET and the lowside

boost MOSFET. The regulators control method

is based upon current mode control using an

emulated current ramp. Emulated current mode

control reduces noise sensitivity of the pulse-width

modulation circuit, allowing reliable control of the very

small duty cycles necessary in high input voltage

applications. Additional protection features include

current limit, thermal shutdown and an enable input.

The device is available in a power-enhanced, 20-pin

HTSSOP package featuring an exposed die attach

pad to aid thermal dissipation.