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TMP390: TMP390 Accuracy Question

Handi Kartadihardja
Intellectual 340 points

Part Number: TMP390

Hi TI,

Regarding the TMP390A3DRLR, could you please clarify the following:

  1. Does the +-3.5K accuracy specification already account for the 1% tolerance of the setting resistors SETA and SETB?
  2. Is the temperature sensed primarily through the package body or via one of the six leads?

Thank you!

 

  • 0
    TI__Genius 16265 points

    Hello Handi,

    1.  The 1% resistor accuracy specification is not part of the temperature accuracy, that requirement exists so that the TMP390 can correctly determine the trip thresholds at power up. So you do not need to add on the 1% resistor accuracy to the temperature accuracy.
    2. Temperature is primarily sensed through the package body.

    Thanks

    -Alex Thompson

  • 0
    Intellectual 340 points

    Hi Alex,

    Thank you for the reply.

    Noted on your comment that 1% resistor accuracy already taken into account of overall temperature accuracy.

    Can I check how TI conducted the test and to verify TMP390 thermal sensing?

    1. Is it conducted through PCB or component next to it act as heat source (this way the component legs will experience higher thermal heat than the package body) OR

    2. It is tested inside temperature chamber - the whole PCB, component's legs, component's body rise of heat will be the same

    Our application requires sensing thermal heat caused by a component failure / overheating, which is populated on the same PCB.

  • 0 in reply to Handi Kartadihardja
    TI__Genius 16265 points

    Hi Handi,

    Great question. We characterize our temperature sensors in stirred oil baths which can be set to many different temperatures. The oil is set to a particular temperature, and completely envelopes the IC which is soldered onto a small PCB. It's a very optimal temperature setup because the heat source is uniform around the sensor so we can characterize the trip point accuracy very well. For your application, I would recommend placing the TMP390 as close as possible to the component you are monitoring, and even using shared copper planes to maximize the ability of heat from the failing component to reach the TMP390.

    Thanks

    -Alex Thompson