AM686HC — single comparator with TTL output in a TO-100-10 can
The AM686HC is a single general-purpose comparator from AMD, delivering a TTL-compatible output with a 15 ns propagation delay. Packaged in a through-hole TO-100-10 metal can, it is built for applications that need fast threshold detection and a clean logic-level output — think line receivers, pulse-width discriminators, and zero-crossing detectors in instrumentation or control logic. The supply requirement is unusual: it needs a dual rail of -5.7 V to -6.3 V and 4.75 V to 5.25 V. That split-supply footprint is a hard constraint — do not plan for a single 5 V rail unless you generate the negative leg. Quiescent current maxes at 42 mA, and input offset voltage is specified at 10 mV at 5 V supply. Common-mode and power-supply rejection are rated at 80 dB CMRR and 60 dB PSRR respectively, giving reasonable noise immunity for a comparator of this era. The operating temperature range is 0°C to 70°C, so this part is suited for commercial indoor equipment — not extended or industrial environments.
15 ns propagation delay — timing margin in TTL systems
The 15 ns propagation delay is the headline speed figure. For a TTL-output comparator, that puts it in the fast lane for the 1970s–80s logic era — fast enough to handle clock recovery or comparator-based timing circuits running at moderate clock rates. If your design needs sub-10 ns response, the AM685DL (6.5 ns, ECL output) is a different animal entirely, but it requires ECL termination and a wider temperature range (-30°C to 85°C).
Package and mounting — through-hole metal can
The TO-100-10 metal can is a 10-lead circular package with a hermetic seal — common in high-reliability and military-grade parts. It mounts through-hole, so plan for a corresponding PCB footprint with a 10-pin circular layout. The metal can provides good thermal dissipation and RF shielding, which is useful in noisy environments.