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TMP431: Beta compensation

na na78
Guru 16770 points
Part Number: TMP431

Hi

Could you please answer the following questions?

1.

Beta compensation register is described in Table 10.

How to detect beta range automatically?

(What is monitored of the transistor?)

2.

In typical application of datasheet, the following sentence is described.

"Based on these criteria, two recommended small-signal transistors are the 2N3904 (NPN) or 2N3906 (PNP)."

And Figure 7 shows remote temperature error of 2N3906 with n-factor.

Does it mean that the calibration is not examined properly if other than these transistors are used?

BestRegards

  • 0
    TI__Guru**** 244400 points
    Hello Forum User,

    1. When the beta selection is set to 1xxx, the TMP431 automatically detects the configuration for the remote sensor, i.e diode connected or collector-GND connected transistor and selects the beta as per the settings for the beta range applied . As for the details on how it is done, we cannot share information more than the datasheet,
    2. The figure-7 is a typical temperature error graph for the connection typologies for the 2N3906. There are multiple other transistors that can be used and it is not an exhaustive list. As a result it is not possible to have Fig-7 for every transistor and still be inclusive for all transistors. This action is left for the application developer to make sure that the transistor is properly calibrated. The recommendation is for transistors that TI has tested the TMP431 with.