LMZ31530: INH Control Using Potential Divider Circuit

SANTANU KUMAR SINHA

Prodigy 175 points

Part Number: LMZ31530
Other Parts Discussed in Thread: LMZ31710

Tool/software:

Hi TI Team,

As per the functional block diagram, there is a potential divider circuit connected to VIN.

Can I use external potential divider with 1 K to VIN and 2K to GND to drive the INH Pin of this device ?

Thanks and Regards,

Santanu Kumar Sinha.

8 months ago

0 Tahar Allag 8 months ago

TI__Mastermind 32440 points

Hello Santanu,

INH in is 7V abs max where as VIN is 20V. Connecting to vin that way (1K and 2K) is risking 13.3V in the INH pin and causes stress and damage.

Thanks

Tahar

0 SANTANU KUMAR SINHA 8 months ago in reply to Tahar Allag

Prodigy 175 points

Hi Tahar,

Thanks for the Info.

I am connecting VIN & PIN to 5V and VOUT is 0.85 V.

In there still a concern using (1K and 2K) combination for potential divider at INH Pin ?

Thanks and Regards,

Santanu Kumar Sinha

0 Tahar Allag 8 months ago in reply to SANTANU KUMAR SINHA

TI__Mastermind 32440 points

Yes, that should be fine. Or just leave it Not connected. This pin has an internal pull-up. If this pin is left open circuit, the device operates when a valid input voltage is applied

0 SANTANU KUMAR SINHA 8 months ago in reply to Tahar Allag

Prodigy 175 points

This is my observation in the actual hardware, i.e. when INH is left open, I am measuring 1.9 V at INH Pin which is just 0.1V above the threshold mentioned in datasheet.

In order to have margin for threshold to higher level and considering variation at higher temperature, I am planning to use the above configuration. Correct me if I am missing anything here ?

Can I implement the the above circuit to drive INH pin LMZ31710 also ?

0 Calan Elaya 8 months ago in reply to SANTANU KUMAR SINHA

TI__Genius 12425 points

Hello Santanu,

Tahar will respond next week as he is out today.

Thank you,
Calan

+1 Tahar Allag 8 months ago in reply to Calan Elaya

TI__Mastermind 32440 points

Hello Santanu,

Yes, you are correct. You can use the 1k and 2K connection to VIN.

Thanks!

Tahar

0 SANTANU KUMAR SINHA 8 months ago in reply to Tahar Allag

Prodigy 175 points

Thank You Tahar.

0 Calan Elaya 8 months ago in reply to SANTANU KUMAR SINHA

TI__Genius 12425 points

Hello Santanu,

If there are no further questions, I will close this thread. If any further questions, please reply. If this helped resolve your issue, please don't forget to click "This resolved my issue"

Thank you,
Calan

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LMZ31530: INH Control Using Potential Divider Circuit