The recommended bias supply voltage range for LM5113-Q1 is from 4.5 V to 5.5 V. The lower end of this range is governed by the internal undervoltage lockout (UVLO) protection feature of the VDD supply circuit. TI recommends keeping proper margin to allow for transient voltage spikes while not violating the LM5113-Q1 absolute maximum VDD voltage rating and the GaN transistor gate breakdown voltage limit.

The UVLO protection feature also involves a hysteresis function. This means that once the device is operating in normal mode, if the VDD voltage drops, the device continues to operate in normal mode as far as the voltage drop do not exceeds the hysteresis specification, VDDH. If the voltage drop is more than hysteresis specification, the device shuts down. Therefore, while operating at or near the 4.5-V range, the voltage ripple on the VDD power supply output must be smaller than the hysteresis specification of LM5113-Q1 UVLO to avoid triggering device shutdown.

A local bypass capacitor must be placed between the VDD and VSS pins. This capacitor must be located as close as possible to the device. A low-ESR, ceramic surface-mount capacitor is recommended. TI recommends using 2 capacitors across VDD and GND: a 100-nF ceramic surface-mount capacitor for high frequency filtering placed very close to VDD and GND pin, and another surface-mount capacitor, 220-nF to 10-μF, for IC bias requirements.