NXP Semiconductors 74HC85N,652

Overview

74HC85N,652 from Nexperia is a 4-bit high-speed CMOS magnitude comparator IC used to determine relative binary word size in digital logic systems. It compares two 4-bit inputs (A0–A3 and B0–B3), delivers mutually exclusive QA>B, QA=B, and QA<B outputs, supports serial/parallel cascading via IA>B/IA=B/IA<B expansion pins, and operates across 2.0–6.0 V supply with propagation delays as low as 11 ns (IA=B → QA=B, VCC = 2.0 V).

For engineers reviewing the 74HC85N,652 datasheet, 74HC85N,652 pinout, 74HC85N,652 application, or 74HC85N,652 equivalent, key selection considerations include cascading latency, supply voltage range compatibility (2.0–6.0 V), TTL-level input thresholds (for HCT variant), standard-output drive capability, and MSI-level integration for embedded control and industrial logic subsystems.

Technical Context

The 74HC85N,652 implements a fully decoded 4-bit magnitude comparison function using static CMOS logic, enabling direct evaluation of A > B, A = B, and A < B states without external gating. Its internal logic supports both serial (daisy-chained) and parallel (feed-forward) expansion schemes for multi-word comparisons up to arbitrary bit widths.

Expansion is controlled via three dedicated cascading inputs (IA>B, IA=B, IA<B) that accept results from less-significant comparators and feed into corresponding outputs (QA>B, QA=B, QA<B). The device requires IA>B = IA<B = LOW and IA=B = HIGH for standalone operation, and all outputs are mutually exclusive under valid input conditions per the function table.

Key Specifications

Pinout & Package

DIP-16 package (plastic dual in-line package, 0.3-inch body width, 2.54 mm pitch), compliant with JEDEC MS-001 and "74HC/HCT/HCU/HCMOS Logic Package Outlines".

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC85N,652, the 74HCT85N,652 offers improved input compatibility with older TTL systems but sacrifices some low-voltage performance, while SN74HC85N provides identical functionality with alternate manufacturing origin and logistics traceability - both serve as drop-in alternatives in most 4-bit compare designs.

Availability

74HC85N,652 is available at Aetrix Electronics and suitable for industrial process controllers, servo-motor control systems, and legacy bus arbitration circuits requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for 74HC85N,652 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

Nexperia is a global semiconductor expert focused on high-volume, high-reliability discrete, logic, and PowerMOS devices for automotive, industrial, computing, and consumer markets.

The 74HC85N,652 belongs to Nexperia's 74HC logic family - engineered for robust, low-power, pin-compatible replacements of legacy TTL comparators in space-constrained and thermally demanding embedded control applications.

FAQ

What is the recommended power supply decoupling for 74HC85N,652?

Each 74HC85N,652 should use a 100 nF ceramic capacitor placed as close as possible between VCC (pin 16) and GND (pin 8). For systems with multiple units or high switching activity, add a bulk 1–10 µF electrolytic capacitor per power rail segment. This minimizes supply noise-induced timing jitter and ensures stable propagation delay performance across temperature and voltage ranges.

How do I configure 74HC85N,652 for standalone 4-bit comparison?

To operate 74HC85N,652 independently, connect IA>B (pin 4) and IA<B (pin 2) to GND, and IA=B (pin 3) to VCC. This initializes the expansion inputs to indicate "no prior comparison result", allowing the device to evaluate only the local A0–A3 and B0–B3 inputs. All three outputs (QA>B, QA=B, QA<B) will then reflect the relationship between those 4-bit words.

Can 74HC85N,652 compare BCD-encoded digits?

Yes, 74HC85N,652 can compare BCD-encoded digits because its magnitude comparison logic is valid for any monotonic code - including binary-coded decimal. When A0–A3 and B0–B3 represent valid BCD nibbles (0–9), the QA>B, QA=B, and QA<B outputs correctly reflect their numeric relationship, making it suitable for digit-level arithmetic in calculators or display drivers.

What is the maximum operating frequency for cascaded 74HC85N,652 configurations?

The maximum usable frequency depends on total propagation delay through the cascade chain. For a 12-bit comparison using three 74HC85N,652 units in series, worst-case delay is ~3 × 195 ns = 585 ns (per AC specs at VCC = 2.0 V), implying a maximum sustained compare rate of ~1.7 MHz. At VCC = 6.0 V, delay improves to ~3 × 42 ns = 126 ns, supporting up to ~7.9 MHz operation.

Is 74HC85N,652 RoHS compliant and halogen-free?

Yes, 74HC85N,652 is RoHS compliant and halogen-free per Nexperia's product compliance documentation. It meets EU Directive 2011/65/EU and IEC 61249-2-21:2011 standards. The DIP-16 package uses lead-free matte tin terminations and environmentally optimized molding compound - verified in Nexperia's official compliance statements dated post-2017.