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.