minimum load resistance for OPA703

Hi Alex,

The answer depends heavily on what voltage you're trying to drive into the load and what voltage the load is terminated to.  The following figure from the datasheet describes the possible output voltage vs. output current of the OPA703 output stage.  If you can determine what current you are trying to deliver into the 100 Ohm load (I = V / R) then you can determine if the output can maintain the proper level or not. So, if you are trying to drive a full signal output of +/-5V or so into a 100Ohm load then it is not possible because providing the requried 50mA is only possible if the ambient temperature is very low (-55C) and if the required output voltage is near mid-supply.

If you are trying to drive larger voltages into the 100 Ohm load then you may want to consider one of our "High Output Current" precision amplifiers which can be found at the link below:

http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?family=analog&familyId=1483&uiTemplateId=NODE_STRY_PGE_T

Best Regards,
Collin Wells
Precision Linear Applications

Hi Alex,

The OPA551 should do the trick with plenty of headroom for additional output current if required.  With a +/-6V supply it should be able to easily maintain a +/-3V output with over 300mA of output current.

Regards,
Collin Wells
Precision Linear Applications