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reference buffer for SAR A/D ? (Read 3201 times)

Ajay

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reference buffer for SAR A/D ?
Apr 30^th, 2012, 12:55pm

I have a SAR A/D converter and I need to make a reference buffer for it. The buffer has a big capacitor of a few micro-Farad connected to it. This acts a voltage source for the capacitive DAC array. What type of an op-amp architecture do I use for the buffer ? A 2 stage miller compensated opamp may not be suitable since the compensation cap. will be in pico-farad only. Any ideas / suggestions will be appreciated. Thanks.

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carlgrace Senior Member Offline Posts: 231 Berkeley, CA	Re: reference buffer for SAR A/D ? Reply #1 - May 11^th, 2012, 1:25pm Single-stage op amps get more stable as you increase the load capacitor. Since you have such a large cap, maybe you should look into a single-stage op amp buffer.
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pixel New Member Offline Posts: 5	Re: reference buffer for SAR A/D ? Reply #2 - May 18^th, 2012, 3:00am In this case type of the output stage and buffer speed are specially �important. What is the resolution clock frequency and total DAC capacitance of your ADC?
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loose-electron Senior Fellow Offline Best Design Tool = Capable Designers Posts: 1638 San Diego California	Re: reference buffer for SAR A/D ? Reply #3 - May 24^th, 2012, 1:30pm you are driving a capacitive load. OTA with a push pull output.
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