LM3485: Driving N-FET

John Lee11

Part Number: LM3485
Other Parts Discussed in Thread: TPS53119

Hi,

I want to use this device because of the hysteretic feature but my design requirement is I have to drive a specific N Channel Mosfet. Is it possible to do this in a Buck Topology?

over 6 years ago

0 Mathew Jacob1 over 6 years ago

TI__Expert 5900 points

John,

LM3485 is designed to be used with a PFET. You can look at alternate parts such as TPS53119 that has a skip mode feature at light loads.

Regards,

Mathew

0 John Lee11 over 6 years ago in reply to Mathew Jacob1

Prodigy 100 points

I tried looking for one that can handle +125C but no avail.

0 Mathew Jacob1 over 6 years ago in reply to John Lee11

TI__Expert 5900 points

Max junction temp range is 150C for TPS53119 similar to LM3485. LM3485 does not specify max ambient temp hence you get the impression it supports 125C ambient. Both parts will work to 150 Tj

Regards,
Mathew

0 John Lee11 over 6 years ago in reply to Mathew Jacob1

Prodigy 100 points

My design is non-synchronous. What should I do if I am not using the high-side low side drv?

0 Mathew Jacob1 over 6 years ago in reply to John Lee11

TI__Expert 5900 points

If doing a async design then you don't use the LDRV signal and just use a diode.

Regards,

Mathew

Power management

Power management forum

LM3485: Driving N-FET