EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Austin on June 18, 2024, 02:11:00 pm
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Hi!
I'm learning how to use the AD9214 ADC IC.
This IC is not recommended for new design but i have few laying around so i decided to use it.
The IC works on single rail power and datasheet says it can read 2Vpp analog signal.
My question is , is it possible to tie the negative input(Ain~) to ground and send in +/-1Vpp signal in to the positive(Ain) input and measure correctly?
And could anyone teach me how this figure22 circuit work?
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My question is , is it possible to tie the negative input(Ain~) to ground and send in +/-1Vpp signal in to the positive(Ain) input and measure correctly?
No. No any inputs can goes below ground.
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Fig. 22 is there mainly to illustrate how input protection and input impedances work. Actual device may or may not actually works as illustrated.
Good practices are to never intentionally forward bias any of the diodes. Keep Vin between supply voltages. Don't go below Vss, don't go above Vdd. If you need bipolar input then either shift Vss down, or shift your signal up.
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Thank you for your reply !
Another question came up in my mind by reading your reply.
If I offset both Ain and Ain~ to half the Vdd, will it work fine?
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You want to bias the inputs at 1/3 of AVdd as described on page 15 of the datasheet. (https://www.analog.com/media/en/technical-documentation/data-sheets/ad9214.pdf)