Hi,
if TMP431 connect FPGA internal BJT as remote sense, but the BJT spec. is higher than TI recommendation on data sheet, item 3 and 4.
1. Base-emitter voltage > 0.25 V at 6 μA, at the highest sensed temperature: OK
2. Base-emitter voltage < 0.95 V at 120 μA, at the lowest sensed temperature: OK
3. Base resistance < 100 Ω --> FPGA resistance is 210 ~ 287 ohm
4. Tight control of VBE characteristics indicated by small variations in hFE (that is, 50 to 150): hfe is 200~ 250.
On this case, can we estimate temperature accuracy or tolerance? How can we calculate?