hii there, am using ad5263 digipot and after the programming i can't measure the resistance (both end to end and Raw / Rwb) through DMM. In other words it (DMM) shows some erroneous value which is continuously changing. Why that happens??

Question

if it is because of some internal circuitry, is it affect affect my signal??. because my signal is highly current and voltage sensitive. 
 thank you in advance. . . .

rrosario · Accepted Answer

When you use the DMM to measure resistance from end to end, what is the voltage across the ohmmeter? This voltage should not exceed VDD or VSS because the diodes connected from the A/W/B terminals will be forward biased if the VDD voltage is exceeded. 
 
 Best regards, 
 Rainier

rrosario · Answer

on your setup, do you have a prototype board and followed the layout guidelines as well as the power supply bypassing recommendations(see page 22 of the data sheet)? I don't see any bypass capacitors on your drawing and this could affect the stability of the part. 
 How does the 70k to 120k resistance changing? is it constantly increasing from power-up or the resistance randomly changing? 
 O1 & O2 not responding with instruction byte may be caused by an incorrect timing or incorrect writing sequence. Were you able to successfully complete a write sequence on a DAC? For us to verify that you are sending the correct sequence, we need to have a scope shot of your digital lines. 
 Best regards, 
 Rainier

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hii there, am using ad5263 digipot and after the programming i can't measure the resistance (both end to end and Raw / Rwb) through DMM. In other words it (DMM) shows some erroneous value which is continuously changing. Why that happens??

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