Texas Instruments CD74HC85M96E4

Overview

CD74HC85M96E4 from Texas Instruments is a high-speed CMOS 4-bit magnitude comparator IC used for binary/BCD code comparison in digital logic systems. It delivers 13 ns typical propagation delay at 5 V, operates from 2 V to 6 V, supports –55°C to 125°C industrial/military temperature range, and features buffered inputs/outputs for noise immunity and fanout of 10 LSTTL loads - deployed in programmable logic controllers and digital instrumentation front-ends.

For engineers reviewing the CD74HC85M96E4 datasheet, CD74HC85M96E4 pinout, CD74HC85M96E4 application, or CD74HC85M96E4 equivalent, key selection criteria include its serial/parallel expandability without external gating, balanced propagation delay/transition times, HC-type supply voltage flexibility (2–6 V), and compatibility with both binary and BCD monotonic codes.

Technical Context

The CD74HC85M96E4 implements a silicon-gate CMOS 4-bit comparator core that evaluates two weighted 4-bit words (A0–A3, B0–B3) and asserts one of three mutually exclusive outputs: A > B, A < B, or A = B. Cascading inputs (A>B IN, A<B IN, A=B IN) enable multi-word comparisons via serial or parallel expansion topologies.

Its logic architecture supports direct LSTTL-compatible operation only in HCT variants; the CD74HC85M96E4 is an HC-type device with CMOS input thresholds (VIH = 3.15 V min at VCC = 4.5 V, VIL = 1.35 V max), 24 pF power dissipation capacitance, and input leakage ≤ ±1 μA over full temperature range.

Key Specifications

Pinout & Package

CD74HC85M96E4 is packaged in a 16-pin SOIC (D package), body size 9.90 mm × 3.90 mm, with standard JEDEC MO-028AC footprint and 1.27 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit magnitude comparator applications.

Compared with CD74HCT85M96 and SN74LS85N, the CD74HC85M96E4 offers broader supply flexibility (2–6 V), lower static/dynamic power, extended temperature support, and superior noise immunity - making it optimal for new designs targeting industrial reliability and energy efficiency.

Availability

CD74HC85M96E4 is available at Aetrix Electronics and suitable for industrial PLC logic modules, digital panel meters, programmable logic controllers, and automotive body control units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC85M96E4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic ICs, with decades of heritage in high-reliability industrial and automotive components.

The CD74HC85M96E4 belongs to TI's CDx4HC85 high-speed CMOS logic family, engineered for low-power, wide-temperature digital comparison tasks in programmable controllers, instrumentation, and safety-critical subsystems.

FAQ

What is the maximum operating frequency supported by the CD74HC85M96E4?

The CD74HC85M96E4 does not specify a maximum clock frequency because it is a combinational logic device with no internal clock. Its usable speed is determined by propagation delay: 14 ns typical (VCC = 4.5 V, CL = 15 pF), enabling reliable operation in systems with signal transitions up to approximately 35 MHz under ideal loading conditions. The CD74HC85M96E4 performance remains stable across its full –55°C to 125°C temperature range.

Can the CD74HC85M96E4 compare BCD-coded values?

Yes, the CD74HC85M96E4 is explicitly designed to compare binary, BCD, or other monotonic codes. Its truth table and functional description confirm correct magnitude evaluation for BCD inputs (e.g., 0000–1001 per digit), provided both operands use identical encoding. The CD74HC85M96E4 does not perform BCD correction or digit carry handling - those functions must be implemented externally.

How should unused inputs be handled on the CD74HC85M96E4?

All unused inputs on the CD74HC85M96E4 - including A0–A3, B0–B3, and cascading inputs (A>B IN, A<B IN, A=B IN) - must be terminated to a valid logic level (VCC or GND) to prevent floating states that cause excessive current draw, oscillation, or erroneous outputs. TI recommends tying unused cascading inputs low (GND) unless actively used in multi-stage configurations. This requirement applies across the full operating temperature range of the CD74HC85M96E4.

Does the CD74HC85M96E4 support mixed-voltage interfacing?

The CD74HC85M96E4 supports mixed-voltage interfacing only on the input side: its CMOS inputs accept VIH ≥ 3.15 V and VIL ≤ 1.35 V at VCC = 4.5 V, allowing reliable connection to 3.3 V logic outputs (which typically drive >2.4 V high). However, its outputs swing rail-to-rail (VOL ≈ 0.1 V, VOH ≈ VCC), so driving 3.3 V-only inputs may require external level shifting when VCC > 3.3 V. This behavior is inherent to the CD74HC85M96E4 HC-family design.

What thermal considerations apply to the CD74HC85M96E4 in high-density PCB layouts?

The CD74HC85M96E4 has a junction-to-ambient thermal resistance (RθJA) of 73°C/W in its SOIC (D) package. At maximum ICC = 160 μA and worst-case VCC = 6 V, static power dissipation is <1 mW - negligible for thermal design. However, dynamic power (PD = VCC² × fi × (CPD + CL)) becomes relevant above 1 MHz; for CL = 15 pF and fi = 10 MHz, PD ≈ 15 mW. Maintain ≥0.5 mm clearance around the CD74HC85M96E4 and use adequate copper pour to ensure safe operation at 125°C ambient.