If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

# TMP709: Do you have any data about temperature response speed?

Part Number: TMP709
Other Parts Discussed in Thread: TMP235

Hello guys,

One of my customers is evaluating TMP709. They have the following questions about temperature accuracy and response speed.

1. What does TE(Temperature error:+/-3 degree C as the Max) mean?

TMP709 temperature threshold level is set by resister value connected from SET pin to GND and this resister value can be calculated by equation (1) on page 8 of the device datasheet.

Is TE calculated with the case of exact resister value calculated by the equation (1) connecting?

Or  is TE calculated with the case of 99%~101% of resister value calculated by the equation (1) connecting?

2. I think TMP709 has delay time from TA temperature reaching to threshold temperature to assert /OT signal because some temperature propagation time from TA to TJ is needed.

Do you have any data about the delay time or temperature response time?

Best regards,

Kazuya.

• Hi Kazuya-san,

1. TE is calculated with ideal resistor.

2. Step response is dominated by the package construction. We don't have step response data for TMP709, but I would expect it to be similar to TMP235 Figure 11.

Thanks,

ren

•  Hi Ren,

Q. I understood that the maximum temperature error is defined in case of the ideal resistor calculated by equation 1 attaching.

However I can see " • Temperature Threshold Set By 1% External Resistor" as one of features on the device datasheet.

Could you pleae tell me what the sentence means? Why is 1% resistor designated?

Thank you again and best regards,

Kazuya.

• Hi Kazuya-san,

1% resistor is specified for marketing purposes. In standard resistor sizes, there is less 'resolution' between a 1% resistor and the next closest 1% resistor. There are more, finer sizes of 0.5% resistor available, for example. A 1% resistor is expected to be adequate for most TMP709 customers both in terms of resistor tolerance (how it contributes to temperature accuracy) and sizes available (temperature set point resolution.)

thanks,

ren

•  Hi Ren,