TMP36 not reading correctly? #clock


Rick Williams - VE7TK
 

I am having some problems with the TEMP1 and TEMP2. The temperature device I am using is a TMP36 (TMP36GT9Z).

When I put the TMP36 on my bench supply at 5 VDC at a temperature of approximately 21C it indicates the correct Vout of 710 mV. When I plug the same device into the clock it reads 680 mV or about 18C. (The supply voltage is unchanged at 5VDC.)

As expected, when I place a finger on the TMP36 the displayed temperature and Vout go up/

It looks to me like something is loading down the TEMP1 and 2 pins when the TMP36 is plugged into the clock board?

Has anyone experienced this? Thanks!
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73, Rick
VE7TK

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