Comparator identity and timing-critical fit
The AD96685BRZ is a single high-speed comparator from Analog Devices, featuring a built-in latch function that holds the output state on command — essential for sampled-data systems like flash ADCs and zero-crossing detectors where the comparison result must be captured at a precise clock edge. Its 3.5 ns maximum propagation delay sets the timing budget for the signal path: from an input overdrive condition to a valid output level, the comparator settles within this window, which defines the maximum clock rate the downstream logic can sample at without missing a transition. The complementary differential ECL open-emitter outputs drive 50-ohm terminated lines directly — the 30 mA typical output current is sufficient to swing a terminated ECL rail without an external buffer.
Noise rejection and threshold accuracy
90 dB typical CMRR means the comparator rejects common-mode noise on the differential inputs by a factor of roughly 31,600 — critical when sensing a small signal riding on a large DC offset, such as a current-sense resistor voltage in a motor phase. 70 dB typical PSRR attenuates supply ripple by 3,160×, so a 100 mVpp ripple on the -5.2 V rail translates to under 32 µV at the input — this keeps the threshold stable in a switching power-supply environment without additional post-regulation.