8 bit DAC with negative output

[Meach_bzh]

DAC with negative output

Hello,

I am currently looking for a solution to generate a negative voltage from a 8-bit DAC.

I need to generate three negative voltage and I have a very low space restriction.

For that reason, instead of just using three voltage inverters after their related regular DACs, I am thinking if it is possible to use only one voltage inverter.
This voltage inverter will then be used to get a negative voltage that will be connected to dual power supply DAC (whose +/- supply votlage will be inverted).

What do you think about this? Is it possible to do such a thing? and do you have ideas that can help me?

Thank you,

Meach

 

[FvM]

DAC with negative output

It's unclear, if you are talking about signal inversion (needs an inverting amplifier) or power supply inversion (needs a DC/DC converter)?
Clearly, an amplifier needs a negative supply, to be able to source a negative signal.

 

[Meach_bzh]

Re: DAC with negative output

I was thinking to use for example for the voltage inverter:
ADM8660 from ADI

So basically instead of using three times a voltage output DAC + a voltage inverter to get three different negative voltages, I was wondering if it is possible to use Dual-Supply DAC (probably supply voltage of +/- 5V) but with their power supply inverted (-/+ 5V instead of +/- 5V) and to get a negative voltage output.

That way, I will only use three DAC and one voltage inverter instead of three DAC and three voltage inverters (which means saving space in my design).


Don't hesitate to ask if it is unclear but basically I want to generate three different voltages (0- -2V) from a digital signal (it is for that reason I thought about maybe the possibility of generating negative voltage from DAC).#


Thank you

 

[FvM]

A dual supply DAC with inverted power supply simply causes a short and will most likely be burnt.

A switched capacitor voltage inverter is suitable to invert supply voltages (with limited current capability) but not invert signals.

If you e.g. want to invert a 0..5V analog signal, use an inverting OP amplifier.

 

[Meach_bzh]

Thank you for your answer FvM.
I was thinking the same thing about the inverter power supply of the DAC....but just in case.

So to your mind, it is better to use a simple DAC and then inverting the signal with an inverting OP amplifier.
Because I told you that I want to have as less component as possible, do you know if DAC having the capabillity to generate negative voltage exists?

Meach.