TMP300: Start-up characteristic

Steve Widener

Part Number: TMP300

We have a TMP300 with TSET = 523K (trip point ~ 107C). At room temperature (27C) we are seeing start-up behavior where V+ rises to 12V and the Vtemp output rises to ~ 2V corresponding to ~ 150C for about 4-5msec. Later (20msec +) the Vtemp settles to ~ 0.78V or ~ 28C.

Is there a specified time where the device will not provide accurate temperature information during power-up? Is there a way to configure the device to avoid false triggering at power-up?

Steve

over 4 years ago

0 Jalen Tate89 over 4 years ago

TI__Genius 9675 points

Hi Steve,

Do you have a schematic in which you could share?

Jalen

0 Steve Widener over 4 years ago in reply to Jalen Tate89

TI__Genius 9575 points

OUT is pulled up to the 12V supply with ~ 2.5K ohms

The +12V supply comes up at 12V/2msec rate.

0 Steve Widener over 4 years ago in reply to Steve Widener

TI__Genius 9575 points

0 Jalen Tate89 over 4 years ago in reply to Steve Widener

TI__Genius 9675 points

Steve,

Can you add a parallel capacitor on the Tset pin as shown below, and see if the problem still occurs?

Jalen

0 Steve Widener over 4 years ago in reply to Jalen Tate89

TI__Genius 9575 points

This has been tried with and without 0.1uF on the TSET line along with the resistor - there is still an overshoot on the temperature and the OUT pin is triggered. We need ot have a way to make sure the OUT pin is not triggered during power-up.

Please confirm / advise

0 Jalen Tate89 over 4 years ago in reply to Steve Widener

TI__Genius 9675 points

Hi Steve,

I found a similar e2e post which you can see here.

The output behavior at start up is going to be dependent on the supply ramp. You can try varying your ramp rate, or adding a larger supply cap.

Jalen

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TMP300: Start-up characteristic