SNOSCY4E March 2015 – October 2018 LMG5200
The recommended bias supply voltage range for LMG5200 is from 4.75 V to 5.25 V. The lower end of this range is governed by the internal undervoltage lockout (UVLO) protection feature of the VCC supply circuit. The upper end of this range is driven by the 6 V absolute maximum voltage rating of VCC. Note that the gate voltage of the low-side GaN FET is not clamped internally. Hence, it is important to keep the VCC bias supply within the recommended operating range to prevent exceeding the low-side GaN transistor gate breakdown voltage.
The UVLO protection feature also involves a hysteresis function. This means that once the device is operating in normal mode, if the VCC voltage drops, the device continues to operate in normal mode as far as the voltage drop does not exceeds the hysteresis specification, VCC(hyst). 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 auxiliary power supply output must be smaller than the hysteresis specification of LMG5200 to avoid triggering device-shutdown.
Place a local bypass capacitor 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.