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Texas Instruments ads7869 1

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Phaneas

Phaneas

Mechanical
Joined
May 17, 2005
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38
Location
EU
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
 
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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

 
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Thanks for the result.

Give yourself a star!
2pt4b3o.gif




Keith Cress
kcress -
 
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