TMP441 remote sensing

Hi

Regarding remote sensing of TMP441,datasheet have description of a recommendation NPN transistor(2N3904).

When the other NPN transistor is used, are there any problems?

Attached is the datasheet of other transistor(2SC4155A-T111-R)

(I am sorry in Japanese)

Best regards,

Itabi

Hi Itabi,

Thanks for using TI E2E forums. The TMP441 datasheet have listed the criteria to select discrete transistors. These recommendations need to be follow to get the best accuracy, if you select a transistor that doesn't meet these criteria your accuracy will be affected. 2N3904 is just an example. I found the datasheet you shared in English as well, but unfortunately that datasheet doesn't have enough information for me to determine if it meets our recommendations. It doesn't have any Typical Performance Characteristics graphs.

" If a discrete transistor is used as the remote temperature sensor with the TMP441/42, the best accuracy can be achieved by selecting the transistor according to the following criteria:

1. Base-emitter voltage > 0.25V at 6µA, at the highest sensed temperature.
2. Base-emitter voltage < 0.95V at 120µA, at the lowest sensed temperature.

3. Base resistance < 100Ω

4. Tight control of VBE characteristics indicated by small variations in hFE (that is, 50 to 150). "

Best Regards,

Mayrim

Hi Mayrim,

Thank you for your reply.

I will confirm the detail characteristics of discrete transistor.

Best Regars,

Itabi