Other Parts Discussed in Thread: ADC3669, LMH6553SDEVAL, LMH5401
Tool/software:
We're considering using the ADC3669EVM for a proof-of-concept system before we design the production solution.
We've not yet procured an ADC3669EVM module. We're still in the planning stage evaluating all our options.
We're using a Koheron PD100-DC photodetector. This variant of the PD100 has a DC-coupled single-ended SMA output (0 Hz to 110 MHz).
Our application requires that DC information be preserved through the signal path but the ADC3669EVM does not have a DC-coupled option. However, we still want to validate whether the ADC3669 IC will be suitable for our production solution with a POC by some means.
We presume the solution will require:
- Modifying the analog front-end components on the ADC3669EVM module to enable differential DC-coupled inputs.
- Something like this:
- Unplace: C66, C63, and C65
- Replace with 0 ohm jumpers: C69, C62, C61, and C68
- Something like this:
- Using an external amplifier to convert the single-ended output of the PD100-DC module to differential before it goes to the DC-modified ADC3669EVM module
- We believe one complicating factor is that the common mode voltage of this DC-coupled differential signal must be at the correct level (VCM = 1.4V) to be compatible with the ADC3669 inputs.
Questions:
- Is there are better solution we should consider?
- Is our approach in the solution we described above valid?
- Is there a TI amplifier dev board we should consider using for the external amplifier?
