CD54HCT85 - 4-Bit Magnitude Comparator

The ’HC85 and ’HCT85 are high speed magnitude comparators that use silicon-gate CMOS technology to achieve operating speeds similar to LSTTL with the low power consumption of standard CMOS integrated circuits.

These 4-bit devices compare two binary, BCD, or other monotonic codes and present the three possible magnitude results at the outputs (A > B, A < B, and A = B). The 4-bit input words are weighted (A0 to A3 and B0 to B3), where A3 and B₃ are the most significant bits.

The devices are expandable without external gating, in both serial and parallel fashion. The upper part of the truth table indicates operation using a single device or devices in a serially expanded application. The parallel expansion scheme is described by the last three entries in the truth table.

Products containing the "CD54HCT85" keyword are: CD54HCT85F3A , CD54HCT85F3A 5962-886720

• Buffered Inputs and Outputs
• Typical Propagation Delay: 13ns (Data to Output at V_CC = 5V, C_L = 15pF, T_A = 25°C
• Serial or Parallel Expansion Without External Gating
• Fanout (Over Temperature Range)
  • Standard Outputs . . . . . . . 10 LSTTL Loads
  • Bus Driver Outputs . . . . . 15 LSTTL Loads
• Wide Operating Temperature Range . . . –55°C to 125°C
• Balanced Propagation Delay and Transition Times
• Significant Power Reduction Compared to LSTTL Logic ICs
• HC Types
  • 2V to 6V Operation
  • High Noise Immunity: N_IL = 30%, N_IH = 30%of V_CC at V_CC = 5V
• HCT Types
  • 4.5V to 5.5V Operation
  • Direct LSTTL Input Logic Compatibility, V_IL = 0.8V (Max), V_IH = 2V (Min)
  • CMOS Input Compatibility, I_l 1µA at V_OL, V_OH

Data sheet acquired from Harris Semiconductor