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LM57: Setting the trip point with a voltage?

Part Number: LM57
Other Parts Discussed in Thread: TMP300, TMP107

Customer requested an automatic temperature trip point in each of their digital modules, to force a heating of the processor when the temperature is below a set point like −35°C for instance. This heating must occur before anything else.  So the setting is from a non-volatile digital potentiometer:  TLP0102‑100.  Original idea was to use a TMP300 switch thermometer, but it is not accurate enough.  The LM57 has a much more accurate trip point.  But for that low temperature range its RSENSE calls for much higher resistances than what the non-volatile digital potentiometer can provide. 

 After reading the LM57 datasheet it is unclear on how he could set the trip point of the device with a voltage instead of a sense resistor.  Please let me know if this is feasible or if you can recommend another temp sensor that would work here?    Also, is there a TINA model that can be  used to simulate the design?

Thanks & regards, John Garrett, TI-AFA

  • Hi John,

    I will get back with you shortly.

    Jalen
  • John,

    Setting the trip point of the LM57 device is an option, but I do not think it would be any more accurate than the TMP300 if used that way.

    Unfortunately, with the digital potentiometer resistance range I am not sure we have any analog temperature sensors to fit your application.

    I will recommend either two digital temperature sensors, either the TMP116n or TMP107 which can program across I2C or UART interface respectively.

    We can take the conversation offline to discuss more.

    Jalen