LM57: LM57 unused SENSE pin

Khoi Nguyen83

Part Number: LM57

I'm looking at using LM57 to turn on heater at 10C, and turn off at 15C.

I figured that I need to pick 5C hysteresis part. However since I only have one trip point, should I tie SENSE2 to ground or leave it floating?

over 7 years ago

0 Aaron Heng over 7 years ago

TI__Mastermind 31600 points

Hi Khoi,

Thank you for reaching out to us. LM57 comes with two favors of hysteresis 5°C and 10°C. The Rsense1 and Rsense2 pins can not be left floating. These two pins are connected in order to determine the trip point temperature. Please refer to the datasheet table 4 of page 20.

Hope this helps. Please let us know if you have further question.

Aaron

0 Khoi Nguyen83 over 7 years ago in reply to Aaron Heng

Expert 1180 points

Thanks.

We are using it to turn on a 10A 12V relay for small enclosure heater Stego 12V, 30W, max 10A inrush.

Attached the schematic and link to the heater. I'm hoping that LM57 is the appropriate this application.

https://www.stego.de/us/products/heating/heaters/8w-13w/

0 Khoi Nguyen83 over 7 years ago in reply to Khoi Nguyen83

Expert 1180 points

Is OK to use regulated 5V supply for LM57 VDD?
The spec said 2.45V to 5.5V so I'm not if the nominal is 3.3V or whether we can use 5V?

0 Ren Schackmann over 7 years ago in reply to Khoi Nguyen83

TI__Mastermind 35895 points

Hi Khoi,

LM57 temperature accuracy is specified for the full range 2.4 to 5.5V with 5V inclusive.

Thanks,
Ren

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LM57: LM57 unused SENSE pin