Dual decade counter in a hand-solderable SOIC
The CD74HCT390MT packs two independent decade counters (divide-by-10) into a single 16-SOIC narrow body (3.90 mm wide, 1.27 mm pitch). Each element has its own clock input, asynchronous reset, and four BCD outputs — so you can build a two-digit counter or frequency divider with one IC and a handful of passives. The 27 MHz count rate means it reliably tracks input pulses up to that frequency; above that, internal propagation delays may cause missed edges. The negative-edge trigger pairs naturally with positive-edge triggered counters in a cascade without needing an inverter between stages.
Supply rails and temperature range
Runs on a 4.5 V to 5.5 V supply — the classic 5 V logic rail. The 74HCT family uses TTL-compatible input thresholds, so it accepts 5 V TTL outputs directly without a level shifter. The -55°C to 125°C operating range covers military temperature grade; the part keeps counting reliably in engine-bay heat or outdoor enclosures. Asynchronous reset clears the counter immediately when the reset pin goes high — no clock edge needed. This is handy for power-on reset circuits or an emergency clear that must happen regardless of clock state.
Lifecycle and compliance
Texas Instruments lists the CD74HCT390MT as Active — no end-of-life notice, suitable for new designs and production builds. ROHS3 compliant, meeting EU RoHS recast requirements.