Tool/software:
Hello all,
We needed to create a circuit capable of fanning out a 50 ohm TTL pulsed DC to 16x 50 ohm loads. Each output requires a rise time ~ ones of nanoseconds and power sourcing capability of ~ 1W peak output (lower average power due to slow pulsing). The LM7171AIMX was selected due to its fast slew rate and its medium-high power driving capabilities. We are basically just using it as a comparator since we only need to send the output voltage to the rails. An actual comparator would have been used but none were found with proper slew rate and drive power capability.
A simulation was performed on PSPICE for TI that looked like the LM7171AIMX was capable of fulfilling the requirements, only taking about 2ns to complete the transition and drive the 50ohm load with ~4V peak pulsed.
However when our first PCB came in, we notice the first 20 ns is spent hanging out at an intermediate voltage level (~1.4V), and then it completes the transition up to ~4V in the last 10ns. Pictures are attached.
Does anyone have experience with this who might have an explanation for the discrepancy in slew rates, or mitigation methods if we do a re-spin of this board to achieve faster switching?
Thank you,
