The IDT54/74FCT521T/AT/BT/CT are 8-bit identity comparators built using an advanced dual metal CMOS technology. These devices compare two words of up to eight bits each and provide a LOW output when the two words match bit for bit. The expansion input IA = B also serves as an active LOW enable input.
The IDT54/74FCT521 family are 8‑bit identity comparators built with advanced dual‑metal CMOS technology. They offer true TTL input/output compatibility, low leakage (<1 pA), high‑drive outputs (‑15 mA IOH, 48 mA IOL), and are available in DIP, SOIC, SSOP, QSOP, CERPACK and LCC packages. Radiation‑tolerant and MIL‑STD‑883‑compliant versions are also offered.
The document lists absolute maximum ratings, DC electrical characteristics (VIH = 2.0 V, VIL = 0.8 V, VOH ≈ 3.3 V typ., VOL ≈ 0.3 V typ.), power‑supply behavior, switching times (propagation delay ≈ 1.5 ns), test circuits, and ordering codes for commercial and military temperature ranges.
| Input leakage | <1 pA (max) |
|---|---|
| Output drive (high) | -15 mA (IOH) |
| Output drive (low) | 48 mA (IOL) |
| VOH (typical) | 3.3 V |
| VOL (typical) | 0.3 V |
VIH is guaranteed at 2.0 V.
The commercial temperature range is 0 °C to +70 °C.
DIP, SOIC, SSOP, QSOP, CERPACK, and LCC packages are available.
VOL is typically 0.3 V.