Other Parts Discussed in Thread: TPS54360,
To Whom it May Concern,
We implemented the low-side switch circuit from your SLVA163 application note and are finding that the MOSFET (PMV213N) is being randomly being damaged in the application. The voltage input to the DC-DC converter is rated from 42V to 48V where the over-voltage circuit was added as customers were hot plugging in the devices. The output of the DC-DC (12Vdc) is connected to an external LCD monitor that draws approximately 1.5A continuously.
Input current (42Vdc): 490mA
Output current (12Vdc output): 1.5A
1. The PCB area where the TPS54360 DC-DC converter is very warm to the touch, we measured approx. 48degC on the case top and about 53degC on the PCB by the chip. We followed the datasheet recommendation for thermal pad dimensions and via's. I am assuming changing the top and bottom copper from 1oz to 2oz may help lower the temperature but I am not sure how much.
2. We are having several units being returned from the field for issues related to the over-voltage circuit consisting of the TPS2400. Many of the issues seem to be related to the MOSFET where the component is obviously damaged. One unit measured a short between the drain and source. One of our engineers changed the filter capacitor ground connection from your application not from the drain side to the source side as they thought the issue was related to the capacitor connection.
It appears the TPS2400 is working as designed, however we are having issues trying to figure out why the MOSFET's are not working on some of these units. Attached is a schematic of the power supply circuit. I am hoping someone could provide us with some recommendations on why the circuit is subject to the MOSFET being damaged as well as why the TPS54360 is becoming over-heated (close to max temp of device).
Thank you in advance,
Melody Witter