Nexperia USA Inc. 74HCT166D,652

Overview

74HCT166D,652 from Nexperia is an 8-bit parallel-in/serial-out shift register with TTL-compatible inputs, asynchronous master reset (MR), clock enable (CE), and serial output Q7. It operates from 4.5 V to 5.5 V, supports -40 °C to +125 °C ambient range, and features edge-triggered clock (CP) with LOW-to-HIGH transition logic. It is used in microcontroller I/O expansion, LED matrix controllers, and serial data conversion circuits.

For engineers reviewing the 74HCT166D,652 datasheet, 74HCT166D,652 pinout, 74HCT166D,652 application, or 74HCT166D,652 equivalent, key selection considerations include its TTL-level input compatibility, synchronous parallel load capability via PE, CE-controlled clock gating, MR-driven asynchronous reset, and SO16 package thermal performance at extended temperature.

Technical Context

This device implements a synchronous 8-stage shift register with dual-path data loading: parallel load occurs on CP's rising edge when PE is LOW; serial shift occurs on CP's rising edge when PE is HIGH and CE is LOW. The internal architecture includes eight D-type flip-flops with gated clock paths and a dedicated asynchronous reset (MR) that forces all outputs LOW regardless of clock state.

Input clamping diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors. Propagation delay from CP to Q7 is 23–60 ns over temperature and voltage (VCC = 4.5–5.5 V), and maximum operating frequency reaches 45 MHz at 25 °C with CL = 15 pF.

Key Specifications

Pinout & Package

74HCT166D,652 is housed in a plastic small outline package (SO16, SOT109-1) with 16 leads and 3.9 mm body width. Pin 1 is marked by a notch or dot; the package is RoHS-compliant and rated for reflow soldering per JEDEC J-STD-020.

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 74HC166D,653, the 74HCT166D,652 offers tighter timing at 5 V and direct TTL interfacing, while SN74LS166N trades power efficiency and temperature range for strict LS-family signal integrity in aging designs.

Availability

74HCT166D,652 is available at Aetrix Electronics and suitable for microcontroller I/O expansion, LED matrix drivers, industrial serial data converters, and legacy bus interface adapters requiring stable component supply across extended temperature and long production lifecycles.

Supply support for 74HCT166D,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

Nexperia is a global semiconductor expert delivering high-performance, reliable, and energy-efficient components for automotive, industrial, computing, consumer, and communications markets.

The 74HCT166D,652 belongs to Nexperia's industry-standard 74-series logic family, engineered for robustness in harsh environments and designed specifically for synchronous data serialization, I/O expansion, and level-tolerant interfacing in industrial control and embedded systems.

FAQ

What is the function of the MR (Master Reset) pin on the 74HCT166D,652?

The MR pin is an asynchronous active-LOW reset that forces all internal register stages and the Q7 output to logic LOW immediately, regardless of clock state or enable conditions. It overrides PE, CE, and CP, providing deterministic initialization or fault recovery without waiting for a clock edge. Its minimum pulse width is 25 ns at VCC = 4.5 V and T = +125 °C.

Can the 74HCT166D,652 operate reliably at 125 °C ambient temperature?

Yes - the 74HCT166D,652 is fully specified and tested for continuous operation from -40 °C to +125 °C. Its static and dynamic parameters, including VIH/VIL thresholds, propagation delay (tpd ≤ 60 ns), and supply current (ICC ≤ 160 μA), are guaranteed across this full range per JEDEC JESD7A and JESD8C standards.

How does the CE (Clock Enable) pin affect timing behavior?

When CE is HIGH, the CP input is disabled - no clock edges are recognized, and the register holds its state regardless of CP transitions. This eliminates metastability risk during clock stretching or bus arbitration. CE must be stable before CP's rising edge; setup time is 16 ns (min) at VCC = 4.5 V and T = +125 °C.

Is the 74HCT166D,652 pin-compatible with the 74HC166D,653?

Yes - both share identical SO16 (SOT109-1) pinout, pin functions, and mechanical footprint. However, they differ electrically: 74HCT166D,652 accepts TTL-level inputs (VIH ≥ 2.0 V), while 74HC166D,653 requires CMOS-level inputs (VIH ≥ 3.15 V at VCC = 4.5 V). Direct substitution is possible only if driving logic meets the stricter HC threshold.