1FEATURES

2• Hermetic Package for Harsh Operating

Environments

• Emulated Peak Current Mode

• Wide Operating Range up to 100V

• Low I Q Shutdown (< 10 μA)

• Drives Standard or Logic Level MOSFETs

• Robust 3.5A Peak Gate Drive

• Free-Run or Synchronous Operation to 1 MHz

• Optional Diode Emulation Mode

• Programmable Output from 1.215V to 80V

• Precision 1.5% Voltage Reference dead•

Programmable Current Limit

• Programmable Soft-Start

• Programmable Line Under-Voltage Lockout

• Automatic Switch to External Bias Supply

• CPGA-20 with No Thermal Shutdown

DESCRIPTION

The LM5116WG is a synchronous buck controller

intended for step-down regulator applications from a

high voltage or widely varying input supply. The

control method is based upon current mode control

utilizing an emulated current ramp. Current mode

control provides inherent line feed-forward, cycle by

cycle current limiting and ease of loop compensation.

The use of an emulated control ramp reduces noise

sensitivity of the pulse-width modulation circuit,

allowing reliable control of very small duty cycles

necessary in high input voltage applications. The operating frequency is programmable from 50 kHz to

1 MHz. The LM5116WG drives external high-side and

low-side NMOS power switches with adaptive dead•

time control. A user-selectable diode emulation mode

enables discontinuous mode operation for improved

efficiency at light load conditions. A low quiescent

current shutdown disables the controller and

consumes less than 10 μA of total input current.

Additional features include a high voltage bias

regulator, automatic switch-over to external bias for

improved efficiency, frequency synchronization, cycle

by cycle current limit and adjustable line undervoltage

lockout. The device is available in a CPGA-20

high temperature ceramic package with the thermal

shutdown feature disabled.