TMP451-Q1: Question about PNP transistor connenction

Johnny Guo

Part Number: TMP451-Q1

Hi team,

We have two questions about TMP451-Q1.

1. For below connection, it says this has better settling time, what does settling time mean here? Why PNP transistor will have better series resistance cancellation in this connection?

2. If the sensing is mainly by PN junction, can we use diode PN for replacement?

Thanks.

Johnny

over 1 year ago

0 Jalen Tate89 over 1 year ago

TI__Genius 9675 points

Hi Johnny,

I'm digging into your first question to provide the best answer. I will get back to you on with more information.

In regards to question 2, you can not use a diode PN junction as replacement. There are some requirements that must be met for the remote BJT/Thermal diode. More information on selecting a Remote Temperature Sensor can be found here in this FAQ.

Jalen

0 Johnny Guo over 1 year ago in reply to Jalen Tate89

TI__Expert 4910 points

Hi Jalen,

Any feedback on question #1?

Thanks.

Johnny

0 Jalen Tate89 over 1 year ago in reply to Johnny Guo

TI__Genius 9675 points

Johnny,

I've found details from the image below on question 1.

Written in Purple is the reason why Diode v=configuration has faster settling.

Written in Black is the reason why Collector GND configuration has better series resistance cancellation.

Jalen

Sensors

Sensors forum

TMP451-Q1: Question about PNP transistor connenction