This document is a detailed introduction of IDT54/74FCT821A/B/C IDT54/74FCT823A/B/C IDT54/74FCT824A/B/C IDT54/74FCT825A/B/C HIGH-PERFORMANCE CMOS BUS INTERFACE REGISTERS
The IDT54/74FCT821/823/824/825 family provides 10‑bit, 9‑bit and 8‑bit buffered CMOS bus interface registers designed for high‑capacitance loads, parity bus interfacing and multi‑user control in both commercial and military applications. Variants A, B and C offer increasing speed and output drive capabilities, with the FAST versions up to 40 % faster than standard parts.
Key features include low input current, clamp diodes on all inputs for ringing suppression, TTL compatible I/O levels, and radiation‑tolerant or MIL‑STD‑883 Class B qualified versions. The datasheet lists absolute maximum ratings, electrical characteristics, power‑supply behavior, and switching timing parameters for designers.
| Input High Level (VIH) | 2.0 V |
|---|---|
| Input Low Level (VIL) | 0.8 V |
| Operating Temperature Range (Commercial) | 0 °C to +70 °C |
The commercial version operates from 0 °C to +70 °C, while the military version is rated from –55 °C to +125 °C.
Yes, all inputs include clamp diodes for ringing suppression.
The registers are TTL input and output compatible.