Texas Instruments ads7869 1

[Phaneas]

Hello,

we are using a Texas Instruments ads7869 Analog to Digital converter chip for a VFD control. It is used to read the motor currents. The chip has also a D/A converter that makes a reference voltage for the overcurrent comperators. The value of this D/A converter changes its value from time to time by its own, especially at cold temperatures.

Had anyone the same problems with that chip?

Kind Regards

Phaneas

 

[Phaneas]

Hi, I found the cause, the read and address bit were set at the same time and caused a phenomenon called "metastable state of D-Flip-Flop" which let the whole chip oscillate and let it do unexpected things

 

[itsmoked]

Thanks for the result.

Give yourself a star!

Keith Cress
kcress -

http://www.flaminsystems.com