We have implemented a test circuit with the LM5117 for the following Design Inputs:
# Name Value Description
1. Iout 3.0 A Maximum Output Current
2. Iout1 3.0 Amps Output Current #1
3. VinMax 55.4 V Maximum input voltage
4. VinMin 18.0 V Minimum input voltage
5. Vout 12.0 V Output Voltage
6. Vout1 12.0 Volt Output Voltage #1
7. base_pn LM5117 National Based Product Number
8. source DC Input Source Type
9. Ta 30.0 degC Ambient temperature
We modified the WebBench circuit to add a Low Pass filter to the LM5117 Vin pin (consisting of a 4.99 Ohm series and a 1uF Ceramic to ground) and an additional power input bulk Capacitor (68uF 100V).
We started testing the circuit and the regulation looked good at lower Vin (<26V), but as we increased the Voltage Input, the circuit fails. The high side MOSFET, LM5117, and Cout has failed on several boards (or some combination of the three parts).
We did add (5 Ohm) series resistors to the gate drives HO and LO and it seems slightly better, but still fails.
Any help or suggestions?
Thanks,
