LM5050-1-Q1: Reverse polarity protection diode current rating

chris svanberg

Prodigy 250 points

Part Number: LM5050-1-Q1

The application schematic Fig.31 has 1A Schottky diodes.

The LM5050 max current draw (pins VS + In) is listed as 763uA.

Would not a BAS40 type work?

over 7 years ago

0 Karikalan Selvaraj over 7 years ago

TI__Genius 16305 points

Hello Chris,

Yes BAS40 would work with 200mA rating.
However reverse standoff voltage has to be greater than application max voltage.

Regards,
Kari.

0 chris svanberg over 7 years ago in reply to Karikalan Selvaraj

Prodigy 250 points

Then a 90V, 200mA, 5ns common anode BAW56 could work?

0 Karikalan Selvaraj over 7 years ago in reply to chris svanberg

TI__Genius 16305 points

Hello Chris,

Yes BAW56 is 70V, rated 250mA and it should work for application less than 70V.

Regards,
Kari.

0 chris svanberg over 7 years ago in reply to Karikalan Selvaraj

Prodigy 250 points

Thanks!

Some version is rated for 100V i.e. BAW56HDWQ-13

0 chris svanberg over 7 years ago in reply to chris svanberg

Prodigy 250 points

I tried the application schematic, fig.8.2.6 and the circuit does not behave as I expected.

With 0.5A running thru a IXTH160N10T (7mOhm, 6.6nF gate) I get gate voltage boost of 5V with 23.5mV across the drain-source path.

With a 1A current limited supply I get no reverse protection with either 25V or 48V, the TVS (D2) diode absorbs the short.
I'm using a 15KPA54ACT.

What am I missing?

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LM5050-1-Q1: Reverse polarity protection diode current rating