Nexperia USA Inc. 74HCT166PWJ

Overview

74HCT166PWJ from Nexperia is an 8-bit parallel-in/serial-out shift register with TTL-compatible inputs, asynchronous master reset (MR), clock enable (CE), and parallel load capability via PE. It operates from 4.5 V to 5.5 V, delivers propagation delay as low as 19 ns (VCC = 5.0 V, CL = 15 pF), and supports synchronous serial expansion in microcontroller I/O port extension circuits.

For engineers reviewing the 74HCT166PWJ datasheet, 74HCT166PWJ pinout, 74HCT166PWJ application, or 74HCT166PWJ equivalent, key selection considerations include its TTL-level input compatibility, 16-pin TSSOP package, -40 °C to +125 °C industrial temperature range, and precise timing parameters for synchronous data chaining in embedded control systems.

Technical Context

This device implements a synchronous 8-stage shift register with dual-path data loading: parallel load occurs on the rising edge of CP when PE is LOW; serial shift occurs on each CP rising edge when PE is HIGH and CE is LOW. The MR input asynchronously clears all flip-flops to logic LOW independent of clock state.

Its architecture includes Schmitt-triggered inputs for noise immunity, clamp diodes enabling overvoltage-tolerant interfacing, and CMOS output stages capable of sourcing/sinking ±4.0 mA at VCC = 4.5 V. Timing is strictly edge-triggered (LOW-to-HIGH CP), with setup/hold times validated down to 15 ns (tsu) and 13 ns (th) at 4.5 V.

Key Specifications

Pinout & Package

TSSOP16 plastic thin shrink small outline package (SOT403-1); 16 leads; body width 4.4 mm; lead pitch 0.65 mm; exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC166PW, the 74HCT166PWJ offers superior noise margin with TTL inputs and faster timing; versus SN74LV165APW, it provides direct 5 V compatibility, integrated MR, and proven industrial temperature resilience without voltage translation.

Availability

74HCT166PWJ is available at Aetrix Electronics and suitable for microcontroller I/O expansion, LED matrix driving, industrial sensor aggregation, and programmable logic interface applications requiring stable component supply across extended temperature ranges.

Supply support for 74HCT166PWJ 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 delivering high-performance, reliable, and energy-efficient components for automotive, industrial, computing, consumer, and communications markets.

The 74HCT166PWJ belongs to Nexperia's industry-standard 74HCT logic family, designed specifically for robust 5 V digital interfacing in noise-prone industrial control and embedded systems where TTL compatibility and wide temperature operation are essential.

FAQ

What is the function of the PE (Parallel Enable) pin?

The PE pin is an active-LOW control that selects between parallel load and serial shift modes. When PE is LOW, the next rising edge of CP loads D0–D7 into the register simultaneously. When PE is HIGH, CP edges shift data serially from DS into the register. This dual-mode operation enables flexible data ingestion without external logic.

Can 74HCT166PWJ operate reliably at 5.5 V supply?

Yes - the 74HCT166PWJ is fully specified up to 5.5 V per JEDEC JESD7A. At this voltage, propagation delay improves to 14 ns (typical), output drive increases to ±5.2 mA, and VIH/VIL margins widen. All DC and AC parameters in the datasheet include 5.5 V test conditions, confirming safe and validated operation.

How does the MR (Master Reset) pin behave during normal operation?

MR is an asynchronous active-LOW input that forces all internal flip-flops and Q outputs to logic LOW regardless of CP, PE, or CE state. It overrides all other controls and asserts within 19 ns (VCC = 4.5 V). During normal operation, MR must be held HIGH (via pull-up resistor or MCU GPIO) to allow register functionality.

Is the 74HCT166PWJ pin-compatible with SO16 packages like 74HCT166D?

No - the 74HCT166PWJ uses TSSOP16 (SOT403-1) with 0.65 mm lead pitch and 4.4 mm body width, whereas 74HCT166D uses SO16 (SOT109-1) with 1.27 mm pitch and 3.9 mm width. Footprints, solder stencil apertures, and reflow profiles differ significantly; direct PCB substitution is not possible without layout revision.