Texas Instruments SN74HC165PW

Overview

SN74HC165PW from Texas Instruments is an 8-bit parallel-load shift register IC used for parallel-to-serial data conversion in microcontroller GPIO expansion and keyboard scanning circuits. It operates from 2 V to 6 V, delivers ±4-mA output drive at 5 V, features complementary serial outputs (QH and QH), and supports clock inhibit functionality. Its TSSOP-16 package enables compact board integration in space-constrained industrial control interfaces.

For engineers reviewing the SN74HC165PW datasheet, SN74HC165PW pinout, SN74HC165PW application, or SN74HC165PW equivalent, key selection criteria include its wide supply voltage range (2–6 V), low ICC (≤80 µA), 13 ns typical propagation delay, and direct parallel-load capability independent of clock state - critical for synchronous input capture in PLC I/O modules and embedded keypad interfaces.

Technical Context

The SN74HC165PW implements a positive-edge-triggered 8-bit shift register with asynchronous parallel load. Data loading occurs on SH/LD low, overriding CLK and CLK INH states; shifting occurs on rising edges of either CLK (with CLK INH low) or CLK INH (with CLK low), enabling flexible clock routing. The device includes gated clock inputs and complementary serial outputs for noise-immune signal transmission.

Its logic architecture supports cascading via SER-to-QH interconnection, allowing multi-byte input expansion without additional control lines. All eight parallel inputs (A–H) are directly enabled during load mode, and the internal register retains state during clock inhibit - essential for deterministic sampling in real-time industrial sensing applications.

Key Specifications

Pinout & Package

TSSOP-16 package (6.60 mm × 5.10 mm), thermally enhanced for surface-mount assembly with 0.65 mm pitch; suitable for automated reflow and high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar parallel-load shift register applications.

Compared with SN74LV165A and SN74HC165N, the SN74HC165PW offers optimal balance of 2–6 V flexibility, TSSOP-16 footprint efficiency, and proven industrial temperature performance - making it the preferred choice for new SMT designs requiring broad supply compatibility and cascading scalability.

Availability

SN74HC165PW is available at Aetrix Electronics and suitable for industrial PLC I/O modules, embedded keypad interfaces, video display control panels, and IoT sensor hub designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74HC165PW 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 company delivering analog and embedded processing solutions, with leadership in logic, power management, and signal chain technologies.

The SN74HC165PW belongs to TI's 74HC logic family, designed specifically for robust, low-power, wide-voltage parallel-to-serial data conversion in industrial automation, consumer electronics, and automotive body control modules.

FAQ

What is the maximum clock frequency supported by the SN74HC165PW?

The SN74HC165PW supports up to 50 MHz typical clock frequency at VCC = 4.5 V and TA = 25°C, with minimum guaranteed fmax of 21 MHz across –40°C to +125°C at 4.5 V. This allows reliable high-speed input sampling in real-time control applications while maintaining setup/hold timing margins per TI's switching characteristics table.

Can the SN74HC165PW operate at 3.3 V supply voltage?

Yes, the SN74HC165PW is fully specified for operation at 3.3 V (within its 2 V to 6 V range). At VCC = 3.3 V, VOH is ≥3.15 V (min), VOL is ≤0.1 V (max), and tpd remains within 18 ns (max) - ensuring clean interfacing with standard 3.3 V microcontrollers and FPGAs without level-shifting circuitry.

How does the clock inhibit (CLK INH) function work on the SN74HC165PW?

When CLK INH is held high, the SN74HC165PW ignores all transitions on both CLK and CLK INH pins, freezing register contents regardless of SH/LD state. This allows deterministic pause of serial shifting during critical MCU interrupt service routines - preserving input state integrity without requiring software synchronization overhead.

Is the SN74HC165PW pin-compatible with other packages in the same family?

Yes, the SN74HC165PW shares identical pin numbering and function mapping with SN74HC165D (SOIC), SN74HC165DB (SSOP), and SN74HC165NS (SO), as confirmed in TI's Pin Configuration and Functions section. All use the same 16-pin layout with SH/LD on pin 1, CLK on pin 2, and QH on pin 9 - enabling drop-in replacement across TSSOP, SOIC, SSOP, and SO packages.

What is the purpose of the complementary QH output on the SN74HC165PW?

The QH output provides the logical inverse of the QH serial output, enabling differential signaling or noise-cancellation techniques. In electrically noisy environments like factory floors, routing both QH and QH to a differential receiver improves common-mode rejection ratio (CMRR), reducing susceptibility to EMI-induced bit errors during long-cable serial data transmission.