LMG3522R030: how to terminate unused output pins?

Hello Tsuyoshi,

There is a 5V voltage regulator inside the LMG3522 that can be used to supply external loads, such as digital isolators for the high-side drive signal. So, if you are using a digital isolator for driving the high side FET, this LDO5V output can be used to provide the VCC of the digital isolator.

As for the FAULT_n and OC_n pins these can be used to detect the faults inside the IC.

FAULT_n pin provides an output that asserts low during a fault condition.

OC_n pin provides an output that asserts low during overcurrent and short-circuit fault conditions. 

We can refer to the 7.3.7.5 Fault reporting section in the datasheet, in that the truth table has been given to identify which type of fault is there based on FAULT_n and OC_n output combination.

As for the TEMP pin, the integrated driver in the LMG3522 IC, senses the GaN die temperature and outputs the information through a modulated PWM signal on the TEMP pin. The typical PWM frequency is 9kHz. At temperatures above 150°C, the duty cycle continues to increase linearly until overtemperature fault happens. When overtemperature happens, the TEMP pin is pulled high to indicate this fault until the temperature is reduced to the normal range. There is a hysteresis to clear overtemperature fault.

You can refer to the 7.3.9 section in the datasheet for more details about the TEMP pin.

Usually, we give FAULT_n, OC_n, and TEMP outputs pins to the controller, so that we can monitor different types of faults, and over-temperature detection of the LMG3522 IC.

We use these pins to probe and monitor different type of faults.

I hope, I have answered your query, please let me know if you have any other query as well.

Best regards,

Rohan

Hello Tsuyoshi-san,

Yes if you don't want to use these pins, you can keep them floating.

Best regards,

Rohan