8.1 Overview

The LM5114 is designed to drive low-side MOSFETs in boost-type configurations or to drive secondary synchronous MOSFETs in isolated topologies. The LM5114 offers both inverting and Noninverting inputs to satisfy requirements for inverting and Noninverting gate drive in a single device type.

8.2 Functional Block Diagram

8.3 Feature Description

The LM5114 is a single low-side gate driver with 7.6-A/1.3-A peak sink/source drive current capability. Inputs of the LM5114 are TTL Logic compatible and can withstand the input voltages up to 14-V regardless of the VDD voltage. This allows inputs of the LM5114 to be connected directly to most PWM controllers. The split outputs of the LM5114 offer flexibility to adjust the turnon and turnoff speed independently by adding additional impedance in either the turnon path or the turnoff path.

The LM5114 includes an under-voltage lockout (UVLO) circuit. When the VDD voltage is below the UVLO threshold voltage, the IN and INB inputs are ignored, and if there is sufficient VDD voltage, the output NMOS is turned on to pull the N_OUT low. In addition, the LM5114 has an internal PNP transistor in parallel with the output NMOS. Under the UVLO condition, the PNP transistor will be on and clamp the N_OUT voltage below
1 V.

Under the UVLO condition, the PNP transistor will be on and clamp the N_OUT voltage below 1 V. This feature ensures the N_OUT remaining low when VDD voltage is not sufficient to enhance the output NMOS. The LM5114 has the features necessary to drive low-side enhancement mode GaN FETs. Due to the fast switching speed and relatively low gate voltage of enhancement mode GaN FETs, PCB layout is crucial to achieve reliable operation. Refer to Layout for details.

8.4 Device Functional Modes