Nexperia USA Inc. 74HCT166DB,112

Overview

74HCT166DB,112 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 enable (PE). It operates from 4.5 V to 5.5 V, supports -40 °C to +125 °C ambient range, and delivers 25 MHz maximum clock frequency at VCC = 4.5 V. It is used in microcontroller I/O expansion, LED matrix drivers, and serial data interface bridging.

For engineers reviewing the 74HCT166DB,112 datasheet, 74HCT166DB,112 pinout, 74HCT166DB,112 application, or 74HCT166DB,112 equivalent, key selection factors include its TTL-level input compatibility, synchronous parallel load capability, MR-active-Low reset behavior, and SO16 package thermal performance under industrial temperature cycling.

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 regardless of clock state.

Its TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V) ensure direct interfacing with legacy 5 V logic families, while CMOS output drive (VOH ≥ 3.98 V at IO = –4.0 mA, VOL ≤ 0.26 V at IO = 5.2 mA) maintains noise margin in mixed-signal systems.

Key Specifications

Pinout & Package

74HCT166DB,112 is supplied in SO16 (SOT109-1) plastic small outline package: 16-pin, 3.9 mm body width, 1.27 mm lead pitch, JEDEC MS-012 compliant. Thermal resistance θJA = 120 K/W (typical), Ptot derates linearly at 12.4 mW/K above 110 °C.

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 SN74HCT166N and 74LV166PW, the 74HCT166DB,112 offers optimal thermal performance in SO16 for industrial reflow processes, guaranteed TTL input compatibility at 5 V, and superior noise immunity (VIH/VIL margins >300 mV) in electrically noisy factory-floor environments.

Availability

74HCT166DB,112 is available at Aetrix Electronics and suitable for microcontroller I/O expansion, LED matrix row drivers, industrial serial interface bridges, and legacy bus data capture requiring stable component supply across extended temperature ranges.

Supply support for 74HCT166DB,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 logic, analog, and MOSFET solutions with focus on efficiency, reliability, and sustainability.

The 74HCT166DB,112 belongs to Nexperia's industry-standard 74HCT logic family, designed specifically for robust 5 V system interfacing where TTL compatibility, wide temperature operation, and industrial-grade packaging are mandatory.

FAQ

What is the function of the MR (pin 9) input?

MR is an asynchronous active-LOW master reset that forces all eight internal flip-flops to logic LOW immediately, independent of clock or enable states. It must be pulled HIGH via a 10 kΩ resistor during normal operation and asserted LOW only during system initialization or fault recovery. Its propagation delay to Q7 is 22–60 ns depending on VCC and temperature.

Can 74HCT166DB,112 operate reliably at 3.3 V supply?

No - the 74HCT166DB,112 is specified only for 4.5 V to 5.5 V operation. At 3.3 V, VIH and VIL thresholds fall outside guaranteed switching ranges, risking metastability and increased propagation delay. For 3.3 V systems, use the pin-compatible 74LV166PW or 74AHC166, both rated down to 2.0 V or 1.65 V respectively.

How does CE (pin 6) interact with CP (pin 7) timing?

When CE is HIGH, the internal clock path is disabled: CP transitions are ignored and no shifting or loading occurs. When CE is LOW, CP rising edges trigger either parallel load (if PE = LOW) or serial shift (if PE = HIGH). CE must be stable for at least 2 ns before and after CP's rising edge to avoid metastability, per datasheet tsu/th requirements.

Is the SO16 package (SOT109-1) RoHS-compliant and lead-free?

Yes - the 74HCT166DB,112 in SO16 package conforms to RoHS Directive 2011/65/EU and is lead-free with matte tin finish. Its MSL rating is Level 1 (unlimited floor life), and it supports standard Pb-free reflow profiles with peak temperature up to 260 °C, verified per J-STD-020.