TMP431: TMp431 remote temperature sensing

Hi Divya,

Please see 8.3.6 Sensor Fault section of the datasheet on how to configure the TMP431 if you do not want to use the DXP/DXN pins for remote temperature sensing.   

"When not using the remote sensor with the TMP43x, the DXP and DXN inputs must be connected together to prevent meaningless fault warnings"

Thanks,

Do I have to configure any of the registesr for remote sensing application?

Thank you...

When I am trying to measure remote temperature, I m getting value as FF..I tried with normal binary and extended binary...In both cases I m getting the same value...But the same code is working for local temperature sensing...

Hi Divya,

Can you please send me a oscilloscope of the the I2C transaction.   

Thanks,

Yea..sure

Kindly share your mail Id

Hi Divya,

Can you please attach to thread.

Thanks,

State 0 : Ideal

State 1 : Start

State 2 : Writing Slave Address ( 10011000)

State 3 : Ack from salve

State 4 : Register Read address ( 00000001)

State 5 : Ack from slave

State 6 : Start

State 7 :  Writing Slave Address ( 10011001)

State 8 : Ack from slave

State 9 : Receiving data from salve (01111111)

Hi Divya,

It looks like this transaction sends back a 0x7F for the remote temperature.  Are you getting this value in both standard and extended mode? 

What are you using as the remote BJT?  Also, can you please read back the status register to see if you have any faults?

Thanks,

Hi,

I am getting 0xff in extended binary format.

FPGA is used as remote BJT.

I read the status register with address 0x02. It is showing as 10010010.

TMP431 circuit diagram is attached for reference.

FPGA_DXP and FPGA_DXN pins are directly connected to DXP and DXN pins of Bank 0 of the FPGA.

Hi Divya,

What FPGA are you monitoring? 

It looks like your Cdiff capacitor is above the max 2200 pF and the series resistance is above the 300 ohm spec. 

1. Can you please remove this capacitor or replace it with one below 2200 pF.

2, Please replace R74 and R75 with smaller resistance values. (R74+R75)< 300 ohm when beta compensation is enabled.

Thanks,