Texas Instruments SN74AS2623N

Overview

SN74AS2623N from Texas Instruments is a dual 4-bit universal shift register with parallel load, synchronous reset, and serial I/O, operating at 5V supply with typical propagation delay of 12 ns and fan-out of 20 TTL loads. It supports shift-right, shift-left, hold, and parallel-load modes in industrial temperature range (–40°C to +85°C).

For engineers reviewing the SN74AS2623N datasheet, SN74AS2623N pinout, SN74AS2623N application, or SN74AS2623N equivalent, key selection factors include synchronous operation timing, dual-register independence, TTL-compatible input thresholds, and availability in PDIP-24 package for legacy board integration.

Technical Context

The SN74AS2623N integrates two independent 4-bit shift registers sharing common clock and mode-control inputs but maintaining separate data paths. Each register supports synchronous parallel loading via L1/L2 and individual serial input (SER A/SER B) with complementary serial outputs (Q0A/Q3A and Q0B/Q3B).

It uses bipolar Schottky TTL (AS) technology, delivering higher speed and lower power than standard TTL while maintaining direct compatibility with 74LS and 74F logic families. All control signals - CLK, S0, S1, MR, and PL - are active-high and edge-triggered on rising CLK.

Key Specifications

Pinout & Package

SN74AS2623N is supplied in a 24-pin plastic dual in-line package (PDIP) with 0.600-inch body width and 0.100-inch lead pitch. Pin 1 is marked by notch or dot; pin numbering follows standard DIP convention.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar universal shift register applications.

Compared with SN74AS2623N, SN74ALS2623N trades speed for power efficiency while SN74F2623N increases speed and drive at higher current draw - both retain identical control logic, pinout, and register architecture for drop-in replacement in existing PDIP-24 layouts.

Availability

SN74AS2623N is available at Aetrix Electronics and suitable for industrial control, legacy system repair, and test equipment design requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74AS2623N 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 U.S.-based semiconductor company specializing in analog, embedded processing, and logic devices with global manufacturing and quality certification.

The SN74AS2623N belongs to TI's 74AS logic family, designed for high-speed digital systems requiring deterministic timing, TTL compatibility, and robust operation in industrial environments.

FAQ

What is the maximum clock frequency supported by the SN74AS2623N?

The SN74AS2623N has a typical propagation delay of 12 ns (CLK to Q), supporting reliable operation up to approximately 35 MHz under standard industrial conditions. Maximum frequency depends on load capacitance and signal integrity; full timing validation requires measurement with actual PCB layout and termination.

Does the SN74AS2623N support asynchronous reset?

No, the SN74AS2623N implements only synchronous reset via the MR (Master Reset) input, which clears all register bits on the next rising edge of CLK. There is no dedicated asynchronous reset pin - this ensures predictable timing behavior in synchronous systems.

Can the two registers in the SN74AS2623N operate independently?

Yes, the SN74AS2623N contains two fully independent 4-bit shift registers sharing only clock and mode-control inputs. Each register has its own serial input (SER A/B), parallel load enable (L1/L2), and output set (QA0–QA3 / QB0–QB3), allowing concurrent but distinct data manipulation.

Is the SN74AS2623N pin-compatible with other 74-series shift registers?

The SN74AS2623N is pin-compatible with SN74ALS2623N and SN74F2623N in the same PDIP-24 package. It is not pin-compatible with SN74LS2623N (which uses different pin assignments for SER and L inputs) or with 74HC/HCT variants due to differing logic families and voltage levels.

What is the recommended power supply decoupling for the SN74AS2623N?

TI recommends a 0.1 µF ceramic capacitor placed as close as possible to the V_CC (pin 24) and GND (pin 8) pins of the SN74AS2623N. For boards with multiple AS-family devices, add a bulk 4.7 µF electrolytic capacitor per power plane section to suppress switching noise and maintain stable 5V rail integrity.