Part Number:ADS8881EVM-PDK
Hi,
I have an issue driving the inputs of the EVM properly. The front end THS4551 seems to have a very low input impedance (<10k) making it hard to drive with normal opamps.
For example I am using it in an optical acquisition system using the TI OPT101 to drive the positive input (as described in the EVM user guide for single ended applications). The result is that the OPT101 cannot drive the input to GND. If the OPT101 outputs the lowest possible value (7mV) when I connect it to the EVM it gest pulled up to 0.7V , effectively clipping any signal.
I only had success using a very low output impedance Buffer (BUF634P powered by +-5V to allow full voltage swing.
Is this how this EVM is supposed to work? What are the input current drive requirements?
Thanks,
Petros
