Texas Instruments SNJ54HC164W

Overview

SNJ54HC164W from Texas Instruments is an 8-bit parallel-out serial shift register with AND-gated dual serial inputs (A, B), asynchronous active-low clear (CLR), and positive-edge-triggered clock (CLK). It operates from 2 V to 6 V, delivers ±4-mA output drive at 5 V, and achieves typical propagation delay of 20 ns - used in LED display expansion and GPIO-constrained industrial control interfaces.

For engineers reviewing the SNJ54HC164W datasheet, SNJ54HC164W pinout, SNJ54HC164W application, or SNJ54HC164W equivalent, key selection criteria include its military-grade temperature range (–55°C to 125°C), CFP-14 package compatibility, AND-gated serial enable logic, and direct-clear functionality for deterministic reset in safety-critical timing paths.

Technical Context

The SNJ54HC164W implements a cascaded chain of eight D-type flip-flops with gated serial data input formed by A and B pins feeding an internal AND gate. Clocking occurs on the low-to-high transition of CLK, shifting all bits one position right while discarding QH and loading the new (A ∧ B) value into QA.

Its asynchronous CLR overrides clock and data, forcing all eight outputs (QA–QH) low immediately. Input thresholds are CMOS-compatible (VIH = 3.15 V min at VCC = 4.5 V; VIL = 1.35 V max), and outputs drive up to 10 LSTTL loads with rail-to-rail swing under load.

Key Specifications

Pinout & Package

SNJ54HC164W is housed in a 14-pin Ceramic Flatpack (CFP) package measuring 9.21 mm × 6.29 mm, rated for hermetic sealing and high-reliability environments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit serial-in/parallel-out shift register applications.

Compared with SN74HC164N and SN54HC164J, the SNJ54HC164W uniquely combines hermetic CFP packaging, MIL-PRF-38535 qualification, and minimal 9.21 mm × 6.29 mm footprint - making it the only option for SWaP-C-constrained, high-reliability embedded systems requiring guaranteed operation across extreme thermal cycles.

Availability

SNJ54HC164W is available at Aetrix Electronics and suitable for LED display expansion, industrial PLC I/O expansion, military data acquisition, and avionics status indication requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SNJ54HC164W 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and aerospace markets.

The SNJ54HC164W belongs to TI's military-grade HC logic family, engineered specifically for high-reliability applications demanding extended temperature operation, hermetic packaging, and MIL-PRF-38535 compliance.

FAQ

What is the maximum clock frequency supported by the SNJ54HC164W at –55°C?

The SNJ54HC164W supports a maximum clock frequency of 21 MHz at VCC = 4.5 V and TA = –55°C, as specified in Section 7.9 of the SCLS115G datasheet. This derating ensures timing margin under worst-case cold-start conditions in aerospace and defense platforms where the SNJ54HC164W is commonly deployed.

Does the SNJ54HC164W require external pull-up or pull-down resistors on its A and B inputs?

No, the SNJ54HC164W does not require external pull-up or pull-down resistors on A or B inputs. Its CMOS inputs have ≤1 μA leakage, and unused inputs must be tied to VCC or GND per TI application report SCBA004 - but intentional floating is prohibited to prevent metastability or shoot-through in the AND gate.

How does the AND-gated input architecture of the SNJ54HC164W improve system reliability compared to single-input shift registers?

The AND-gated A/B inputs of the SNJ54HC164W enforce dual-control logic: data only shifts when both signals are asserted. This prevents spurious clock-induced shifts during power-up, reset, or noise events - a critical advantage in safety-critical systems where unintended output transitions could trigger hazardous states.

Can the SNJ54HC164W drive LEDs directly without current-limiting resistors?

No - although the SNJ54HC164W provides ±4-mA output drive at 5 V, direct LED connection without series resistors risks exceeding absolute maximum output current (±25 mA) and violating recommended operating conditions. External 220–470 Ω resistors are required per output to limit current to safe levels for common indicator LEDs.

What is the purpose of the CLR pin on the SNJ54HC164W, and how does it differ from a synchronous reset?

The CLR pin on the SNJ54HC164W is an asynchronous active-low clear that forces all eight outputs (QA–QH) to logic low immediately, regardless of CLK state or timing. Unlike synchronous resets, which wait for the next clock edge, CLR guarantees sub-10 ns reset assertion - essential for fault containment in avionics and industrial safety circuits where the SNJ54HC164W is applied.