All of the examples in the OPA695 datasheet show the device driving a 100 ohm load. When driving a 50 ohm load, the exanples put a series 50 ohm resistor at the output of the OPA695. We need to send a 40nS linear ramp every 16uS with the maximum voltage swing allowed by the OPA695. Simulations show that I can get a visibly linear response to a 40nS ramp with a 6.2 volt peak to peak output voltage into 50 ohms. The output current is about +/- 3.1V/50ohm = 62mA which is within the 85C spec of +/-70mA. The amplifier output directly drives a 6" micro coax cable which has a 50 ohm termination to ground at the end. Will this work? Will the amplifier oscillate without a series 50 ohm resistor?
Also, if I increase the input signal such that I approach 70mA at the output, I get some visible nonlinear response to the 40nS ramp which is acceptable to us. However, will the device be damaged? Is this effect modeled correctly in the simulation?
I am applying a +/- 5.4V power supply in the simulation. Will this burn out the device when driving a 50 ohm load? (The power supply spec is +/-6V max, +/-6.5 absolute max.)
The OPA695 is being directly driven by a DAC with a differential +/-25mA current output. The feedback resistor is 500 ohms. The OPA gain is 166 ohms. We are in the design phase.