LMR14050: How to set the EN pin to GND

Jason Hu27

Part Number: LMR14050

Dear Sir, I want to use the NMOS to control the LMR14050's EN pin, so I connect the NMOS's Drain pin to the LMR14050's EN pin. The Source Pin of NMOS is connected to GND pin. I just control the Gate pin of NMOS. My question is whether I must add a resister(Please refer to below figure, R90 is need?) between LMR14050's EN pin and NMOS's Drain pin? Thanks.

over 7 years ago

0 Gavin Wang (Zejing) over 7 years ago

TI__Expert 3480 points

When mos on, EN is connected to BAT_1 to disable. What's BAT_1 ? For EN pin, pull below 1.2 V to disable. Float or connect
to VIN to enable.

0 Andy Chen over 7 years ago

TI__Mastermind 34625 points

Hi,

R90 is not needed as EN pin only source out 4.6uA, we suggest to place R90 10K between VIN and EN for fast EN pin voltage ramp up when Q7 is turn-off.

0 Jason Hu27 over 7 years ago in reply to Andy Chen

Intellectual 910 points

Dear Andy, thanks for your help. Best regards.

0 Jason Hu27 over 7 years ago in reply to Gavin Wang (Zejing)

Intellectual 910 points

Dear Gavin, the BAT_1 is GND. But I got the answer from another TI employee, he suggest me the R90 is not essential to pull down the EN pin. Thanks for your support. Best regards.

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LMR14050: How to set the EN pin to GND