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AD8000 not working when configured as a noninverting amp

Question asked by gt_engineer on Oct 30, 2015
Latest reply on Nov 25, 2015 by JinoL

Greetings,

 

We are evaluating AD8000 (8-Lead SOIC package) by soldering it to its compatible eval. board, UG-084.

 

When we configure the AD8000 as an Inverting amplifier, things seem to work fine. However, when it is configured as a noninverting amplifier based on Figure 50 of the data sheet there is no output. The data sheet can be found here: http://www.analog.com/media/en/technical-documentation/data-sheets/AD8000.pdf.

 

The feedback network resistors for the noninverting configuration are: RF=RG=432 per Table 5 on the data sheet. I have recorded how the output behaves when the chip is being supplied with +/- 5V. You may find the video here: https://youtu.be/_CJhGnyRB-I. In the video, you will see that during power off, the output (yellow curve) rests at low level. When I turn on the power ( you will hear a beep) the output seems to produce a waveform and then slowly rises until it reaches a high level. The input to AD8000 is 5mV RMS sinusoidal waveform.

 

Also when in noninverting mode, the current on the +5V rail is 42mA and 6mA for -5V rail. However, if configured as inverting amplifier, both rails consumes about 14mA which should be normal.

 

Please Help.

 

Thanks,

 

David

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