Power Supply for an ADS8332

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#1
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Hi,

 

I have a question about an external ADS8332 I'm using.

On the datasheet, it says that it needs +/-10V to use the full reference voltage range from 0-4.096V, and power the 5V regulator.

 

My question is, to get started with the board, do I need it right now? In the attached screenshot, you can see that at one time they say you 'should' connect the +/-10V, and in the table they say 'yes' it's required.

 

And if I do get a power supply, what current would I give along with the +/-10V?

 

Thanks

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That's a Texas Instruments (TI) product: http://www.ti.com/product/ADS8332

 

You should contact TI for support with their products!

 

http://www.ti.com/product/ADS8332/support

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That is a board, not the ADC, itself. ADC does not require +/-10V. You need to read more about the board operating conditions.

 

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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You should contact TI for support with their products!

 Good idea, thanks. I just posted to their forum

 

That is a board, not the ADC, itself. ADC does not require +/-10V. You need to read more about the board operating conditions.

Oh right, that's a good distinction.

I'm thinking I can bypass the op-amp and use an external voltage reference, in which case I don't believe I need the 10V.  

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ka7ehk wrote:
That is a board

The "ADS833xEVM" board - which is also a TI product!

 

http://www.ti.com/tool/ADS8332EVM

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Oh, I see what you're getting at - it's not having to do with Atmel..

I don't mean to contaminate the forums.. I am using it with an Xmega

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No, nothing at issue about non-Atmel. 

 

My point is that you have TWO sets of specs. One is for the device ADS8332, itself. Those +/-10V requirements are for the EVK board and have little to do with the ADC directly. The power requirements for those are a composite of the ADC and the voltage regulators and anything else that might draw power from those supply rails. You cannot tell just by looking at the ADS8332 specs.

 

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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No, nothing at issue about non-Atmel. 

 

My point is that you have TWO sets of specs. One is for the device ADS8332, itself. Those +/-10V requirements are for the EVK board and have little to do with the ADC directly. The power requirements for those are a composite of the ADC and the voltage regulators and anything else that might draw power from those supply rails. You cannot tell just by looking at the ADS8332 specs 

Ah I understand now, thanks.

TI got back to me, and the op-amps, and voltage regulators need the 10V supply.

 

Would you see any problem in bypassing the op-amps and using an external 5V reference to avoid using a 10V supply?

One op-amp filters the reference voltage before it reaches the ADC, and the another drives the ADC input. 

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Would you see any problem in bypassing the op-amps

Maybe.

 

Do you have a schematic for the evaluation board?

 

If so, then one can easily see what powers the ADC, and what parts of the circuit can be ignored.

 

If you omit the on board op-amp driver then you will need to carefully think about your signal.

What is the bandwidth of your signal, do you need a Nyquist-Shannon LPF on the front end?

Do you need to buffer the output from the source of the signal, i.e. what can the signal source output "drive"?

Do you need to level clamp the input signal, to omit negative voltages, or to clamp over voltages on the input signal?

 

The analog front end often does all of those functions for you.

Hence it may or may not be wise to by-pass what has already been designed into the system, especially if you don't intend to re-design the analog front end yourself, (which you would do to meet certain requirements for the signal processing, depending upon the signal).

 

JC