DAC3154 outputs

Bailin,

We are looking into this.

Regards,

Jim

Hi,

From what I see in the schematics for the DAC3174 EVM (attached) the default configuration is already DC coupled from the DAC to the modulator.   Since the DAC is a dual channel the EVM was made with a quadrature modulator as the default output, DC coupled from the DAC to the modulator with an LC lowpass filter after the DAC.   There are *options* on the EVM to remove a zero ohm resistor that steers the DAC towards the modulator and instead steer the signal towards a balun and transformer for each channel and of course the transformer is naturally an AC coupled path.  But that path is DNI (do not install) by default.  Is that perhaps what you were looking at?  The DAC3171 EVM being single channel does not have the quadrature modulator and thus the default output from the EVM is the transformer coupled output.

Also, below is a link to a TI Design that extensively covers DC coupled and AC coupled designs around the DAC3484, which is a current sourcing DAC and the design material would be directly applicable to our other current sourcing DACs such as the DAC3174.

http://www.ti.com/lit/ug/slua647a/slua647a.pdf

 

Regards,

Richard P.

DAC31X4EVM_B-SCH.pdf

Hi Richard,

Thank you very much indeed for your reply.

If we need different types of outputs instead of from a modulator, what does the circuit with op-amps such as OPA695 at the output stages look like?

Kind regards,

Bailin

Hi,

Take a look at the datasheet for the THS3215.  On the front page of that datasheet is the simplest of DC coupled connections from the DAC straight into the amp.

Regards,

Richard P.

Hi Richard,

Thank you very much.

Can I use  an OPA695 in the place of a THS3215 for this purpose?

Best regards,

Bailin

Hi,

I am not familiar with the OPA695.  I would suggest asking this in the forum for the high speed amplifiers. 

Regards,

Richard P.