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Reference output voltage on AD669 too low

Question asked by poleskiewicz on Dec 3, 2014
Latest reply on Dec 8, 2014 by msamera

I have a board with AD669 (PDIP package), powered by an external power supply and three voltage regulators (+15V, -15V, +5V), working in the bipolar configuration (wired up as recommended on the page 16 of the AD669BNZ datasheet, with 50Ohm resistors connecting the REF OUT, REF IN and BIP OFFSET).

 

Even though the V_EE, V_CC and V_LL are all on correct levels (-15V, +15V and +5V respectively), and the DAC is not puling more than 12mA of current, REF OUT (on pin 28) outputs -4.65V, instead of the documented +10V. What could be the reasons for this happening? Is the DAC working, but is not wired properly? Or has it been broken?

 

Many thanks.

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