NXP Semiconductors 74HC166D,652

Overview

74HC166D,652 from Nexperia is an 8-bit parallel-in/serial-out shift register with synchronous parallel load (PE active LOW), serial shift (DS input), clock enable (CE active LOW), and asynchronous master reset (MR active LOW). It operates from 2.0 V to 6.0 V, supports -40 °C to +125 °C, and delivers 45 ns typical propagation delay (VCC = 4.5 V) for high-speed data serialization in microcontroller I/O expansion circuits.

For engineers reviewing the 74HC166D,652 datasheet, 74HC166D,652 pinout, 74HC166D,652 application, or 74HC166D,652 equivalent, this device serves as a cost-effective, CMOS-compatible serial interface bridge for GPIO-constrained embedded controllers-especially where parallel-to-serial conversion, LED matrix scanning, or SPI peripheral chaining is required.

Technical Context

The 74HC166D,652 implements an 8-stage synchronous shift register with dual-path input control: when PE is LOW, all eight parallel inputs (D0–D7) are latched on the rising edge of CP; when PE is HIGH, serial data enters via DS on each CP rising edge. CE must be LOW to enable clocking-HIGH disables CP entirely.

Its asynchronous MR input forces all internal flip-flops to logic LOW regardless of clock state, enabling immediate reset without waiting for clock edges. Input clamp diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors-critical for mixed-voltage system integration.

Key Specifications

Pinout & Package

74HC166D,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; pin numbering follows standard SO16 counterclockwise layout.

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,652, the 74HCT166D,653 offers superior voltage-level compatibility with legacy 5 V systems, while the SN74LV165APWR trades control flexibility (no MR/CE) for speed and 3.3 V optimization-making each suitable for distinct voltage architecture and timing-critical contexts.

Availability

74HC166D,652 is available at Aetrix Electronics and suitable for industrial sensor interfaces, LED display controllers, and microcontroller I/O expansion requiring stable component supply across extended temperature ranges.

Supply support for 74HC166D,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 logic, analog, and MOSFET solutions optimized for efficiency and miniaturization in industrial and consumer electronics.

The 74HC166D,652 belongs to Nexperia's industry-standard 74HC logic family-designed specifically for robust, low-power, wide-supply-voltage serial/parallel data conversion in space- and cost-constrained embedded systems.

FAQ

What is the maximum clock frequency supported by the 74HC166D,652?

The 74HC166D,652 supports a maximum clock frequency of 24 MHz at VCC = 4.5 V and -40 °C to +125 °C ambient, based on worst-case propagation delay (45 ns) and setup/hold timing margins. At 25 °C and VCC = 6.0 V, fmax reaches 68 MHz, but industrial designs should derate per datasheet limits.

Can the 74HC166D,652 be used with a 3.3 V microcontroller without level shifting?

Yes-the 74HC166D,652 operates reliably at VCC = 3.3 V, and its CMOS inputs accept VIH ≥ 2.31 V (70% of 3.3 V) and VIL ≤ 0.99 V (30% of 3.3 V), matching standard 3.3 V logic thresholds. No level shifter is needed for direct connection to 3.3 V GPIOs.

How does the master reset (MR) interact with clock enable (CE) and parallel enable (PE)?

MR is fully asynchronous and overrides all other controls: when MR = LOW, all eight register stages force Q0–Q7 to logic LOW immediately, regardless of CE, PE, or CP state. CE and PE only affect normal operation when MR = HIGH.

Is the 74HC166D,652 pin-compatible with the 74HC165 or 74HC595?

No-it is not pin-compatible with either. The 74HC165 is a parallel-in/serial-out shift register with different pin assignments (e.g., SH/LD instead of PE, no Q7 output pinout match), and the 74HC595 is serial-in/parallel-out with Q0–Q7 outputs on pins 15–7. Direct substitution requires PCB redesign.