NXP Semiconductors 74HCT147N,652

Overview

74HCT147N,652 from NXP Semiconductors (formerly Philips) is a 10-to-4 line priority encoder IC that converts nine active-LOW decimal inputs (A0–A8) into four active-LOW BCD outputs (Y0–Y3), with A8 assigned highest priority. It operates at 4.5 V supply, delivers 44 ns typical propagation delay, and supports industrial temperature range (−40 °C to +85 °C) for switch encoding in panel control systems.

For engineers reviewing the 74HCT147N,652 datasheet, 74HCT147N,652 pinout, 74HCT147N,652 application, or 74HCT147N,652 equivalent, this page provides verified functional behavior, validated pin assignments, confirmed BCD encoding logic, and real-world use cases in decimal input decoding where priority resolution and TTL-compatible voltage thresholds are required.

Technical Context

The 74HCT147N,652 implements priority encoding using active-LOW inputs and outputs, where simultaneous assertion of multiple inputs resolves to the highest-priority code (A8 > A7 > … > A0). Its HCT logic family ensures TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) while driving standard CMOS loads.

Encoding includes implied "zero" detection: when all nine inputs (A0–A8) are HIGH, all four outputs (Y0–Y3) go HIGH - a defined BCD representation of decimal 0. No external pull-ups are required due to standard output drive capability and defined quiescent current behavior per MSI ICC category.

Key Specifications

Pinout & Package

74HCT147N,652 is supplied in a 16-pin dual in-line package (DIP) with through-hole mounting. Pin 16 is VCC, Pin 8 is GND, Pins 9/7/6/14 are active-LOW BCD outputs Y0–Y3, Pins 11/12/13/1/2/3/4/5/10 are active-LOW decimal inputs A0–A8, and Pin 15 is not connected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar priority encoder applications.

Compared with 74HC147N,652 and SN74LS147N, the 74HCT147N,652 uniquely balances TTL input compatibility, CMOS efficiency, and guaranteed implied-zero encoding - making it optimal for upgrading industrial controls without modifying input circuitry or sacrificing reliability.

Availability

74HCT147N,652 is available at Aetrix Electronics and suitable for industrial HMI panels, legacy system retrofits, and BCD-based instrumentation requiring stable component supply across extended product lifecycles.

Supply support for 74HCT147N,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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications.

The 74HCT147N,652 belongs to NXP's legacy 74HCT logic family, designed specifically for seamless migration from bipolar TTL to low-power CMOS in industrial control, instrumentation, and panel interface systems.

FAQ

What is the input voltage compatibility of the 74HCT147N,652?

The 74HCT147N,652 features TTL-compatible input thresholds: VIH ≥ 2.0 V and VIL ≤ 0.8 V at VCC = 4.5 V to 5.5 V. This allows direct interfacing with 74LS, 74F, and many microcontroller GPIOs without level-shifting. The 74HCT147N,652 does not require external pull-up resistors on inputs, as its inputs are fully specified for TTL logic levels.

How does the 74HCT147N,652 handle the decimal "zero" case?

The 74HCT147N,652 encodes decimal zero when all nine inputs (A0–A8) are HIGH, resulting in all four outputs (Y0–Y3) driven HIGH. This "implied zero" behavior is built into the logic design and requires no external components. The 74HCT147N,652 guarantees this state is stable and meets timing specs across its full operating temperature range.

Is the 74HCT147N,652 pin compatible with the 74LS147?

Yes, the 74HCT147N,652 is pin compatible with the 74LS147 in the 16-pin DIP package, sharing identical pin assignments for VCC, GND, inputs (A0–A8), outputs (Y0–Y3), and n.c. Pin 15. The 74HCT147N,652 maintains the same footprint and signal routing, enabling direct replacement in existing LS-based PCBs without layout changes.

What is the maximum clock or data rate supported by the 74HCT147N,652?

The 74HCT147N,652 is not a clocked device but a combinatorial priority encoder. Its usable data rate is governed by propagation delay: 44 ns typical (An to Yn, CL = 50 pF). This supports reliable operation up to ~10 MHz in systems with adequate setup/hold margins. The 74HCT147N,652 does not include internal latching or clocking circuitry.

Does the 74HCT147N,652 require external pull-up resistors on its inputs or outputs?

No, the 74HCT147N,652 does not require external pull-up resistors on inputs or outputs. Its inputs are TTL-compatible and internally biased to recognize HIGH/LOW states without external biasing. Outputs drive standard loads actively and can source/sink sufficient current for direct connection to LS-TTL or CMOS inputs. The 74HCT147N,652 functions correctly with only VCC and GND connections in typical switch-encoding applications.