[strange problem] ADT75 temperature sensor on i2c

Other Hardware Sensors
1

Hi,

I have a strange problem. I am reading two ADT75 via i2c, but ONE of the sensors fails on temperatures above approx. 34°C.

These guys are very small surface mounted chips, so in I soldered them with tiny copper wires on some small stripe-board. One is on address 0x048 the other one on 0x049 (Pin 7 (A0) connected to VDD). The other address pins are open.

I tested several values for Pull-up resistors. No change.

So did I killed one while soldering? DId someone encountered similar problems (even on other i2c devices)? Any other ideas?

Best regards,
Carsten

2

HI Carsten,

what happens if you only connect the "failing" one does it show the same behaviour?

Do you have a link to the datasheet of teh ADT75? there might be a reset command? never give up hope :slight_smile:

3

Given your sensor is this one: www.analog.com/static/imported-files/data_sheets/ADT75.pdf, you have to solder the address pins that are not on Vcc to GND. A floating pin (not connected) may switch to high, maybe that could be driven even by a higher temperature.

4

Oh! Good advice. I try that.

Sorry for the late reply, notify was not on.

Carsten