Nexperia USA Inc. 74HC166DB,112

Overview

74HC166DB,112 from Nexperia is an 8-bit parallel-in/serial-out shift register with synchronous parallel load, serial shift, and asynchronous master reset. It operates from 2.0 V to 6.0 V, features CMOS-level inputs, edge-triggered clock (LOW-to-HIGH), and delivers propagation delay as low as 14 ns at VCC = 6.0 V - used in microcontroller I/O expansion and LED matrix controllers.

For engineers reviewing the 74HC166DB,112 datasheet, 74HC166DB,112 pinout, 74HC166DB,112 application, or 74HC166DB,112 equivalent, key selection criteria include parallel-load timing (tSU = 17 ns @ VCC = 6.0 V), serial output Q7 drive capability (VOH ≥ 5.48 V @ IO = −5.2 mA), master reset assertion time (tW = 17 ns), and SO16 package compatibility with legacy PCB footprints.

Technical Context

This device implements a synchronous 8-stage shift register with dual-path data loading: parallel data (D0–D7) loads on PE LOW + CP rising edge; serial data (DS) shifts in on PE HIGH + CP rising edge. CE enables/disables clock propagation - active LOW - allowing precise control over shift timing without clock gating.

The architecture includes an asynchronous active-LOW master reset (MR) that clears all flip-flops independently of CP, and input clamp diodes enabling safe interfacing to voltages exceeding VCC when current-limiting resistors are used. All inputs meet JEDEC JESD7A (2.0–6.0 V) and JESD8C (2.7–3.6 V) standards.

Key Specifications

Pinout & Package

74HC166DB,112 is supplied in SO16 (SOT109-1) plastic small outline package: 16-pin, 3.9 mm body width, 1.27 mm pitch, gull-wing leads.

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 74HC166DB,112, the 74HCT166DB,112 offers guaranteed TTL input compatibility at 5 V but sacrifices some noise margin below 4.5 V; SN74HC165PWR provides inverted output and higher package density but removes critical hardware controls (MR, CE), increasing firmware complexity and reducing fault resilience.

Availability

74HC166DB,112 is available at Aetrix Electronics and suitable for industrial sensor interfaces, LED matrix controllers, microcontroller I/O expansion, and legacy bus protocol emulation requiring stable component supply across extended temperature ranges.

Supply support for 74HC166DB,112 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 with focus on efficiency, miniaturization, and sustainability.

The 74HC166 belongs to Nexperia's HC logic family - designed for low-power, wide-supply industrial and automotive-qualified applications where noise immunity, timing predictability, and long-term supply stability are critical.

FAQ

What is the maximum clock frequency supported by 74HC166DB,112?

The maximum clock frequency is 68 MHz at VCC = 6.0 V and Tamb = 25 °C, decreasing to 24 MHz at −40 °C to +125 °C per datasheet Table 7. This is determined by the 14 ns typical CP-to-Q7 propagation delay and 6 ns input transition time - verified under CL = 50 pF load conditions.

Can 74HC166DB,112 operate reliably at 3.3 V supply?

Yes - the device is fully specified from 2.0 V to 6.0 V. At VCC = 3.3 V, VIH = 2.31 V (min), VIL = 1.09 V (max), and tPD = 22 ns (max), meeting standard 3.3 V LVTTL logic thresholds. Input clamp diodes remain functional, supporting safe interfacing to 5 V signals with current-limiting resistors.

Is the master reset (MR) pin truly asynchronous?

Yes - MR is asynchronous and active LOW. When asserted, it forces all internal flip-flop outputs (Q0–Q7) to LOW immediately, independent of CP, PE, or CE states. Recovery requires MR release followed by at least one valid CP rising edge to restore normal operation, as confirmed in the function table (Table 3).

Does 74HC166DB,112 support hot insertion or live swapping?

No - the device lacks hot-swap protection circuitry. Applying VCC before GND, or connecting inputs before power stabilization, may cause latch-up or excessive ICC due to internal clamp diode conduction. Always follow proper power sequencing: GND first, then VCC, then inputs - per Absolute Maximum Ratings (Table 4) and JEDEC JESD78 Class II Level B compliance.