STMicroelectronics M74HC166RM13TR

Overview

M74HC166RM13TR from STMicroelectronics is a high-speed CMOS 8-bit parallel-in/serial-out (PISO) shift register with gated clock, asynchronous clear, and SHIFT/LOAD control. It operates from 2V to 6V, delivers 63 MHz max clock frequency at 6V, supports ±4 mA symmetrical output drive, and features 28% VCC noise immunity. Used in microcontroller I/O expansion, LED matrix scanning, and serial data conversion interfaces.

For engineers reviewing the M74HC166RM13TR datasheet, M74HC166RM13TR pinout, M74HC166RM13TR application, or M74HC166RM13TR equivalent, key selection factors include its TSSOP-16 package, PISO functionality with synchronous parallel load and serial shift modes, low 4 µA quiescent current, and compatibility with 74-series logic timing and levels.

Technical Context

The M74HC166RM13TR implements an 8-stage D-type flip-flop chain with dual-path input selection: parallel data (A–H) loaded synchronously on rising clock edge when SHIFT/LOAD is low, or serial data (SI) shifted right on each rising clock edge when SHIFT/LOAD is high. Clock enable (CLOCK INH) is active-low and must be held high only when CLOCK is high.

It features asynchronous active-low CLEAR that overrides all inputs including clock, forcing all Q outputs low. All inputs include ESD protection diodes, and propagation delays are balanced (tPLH ≅ tPHL), with typical tPHL = 26 ns at VCC = 6V and CL = 50 pF.

Key Specifications

Pinout & Package

TSSOP-16 (Thin Shrink Small Outline Package), 4.9 mm × 6.4 mm body, 0.65 mm pitch, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PISO shift register applications.

Compared with SN74HC165PW and 74LV165APW, the M74HC166RM13TR uniquely provides dedicated QH output, exact 74-series pin/function compatibility, and superior noise immunity-making it optimal for drop-in 74LS166 upgrades and noise-critical serial interface layers.

Availability

M74HC166RM13TR is available at Aetrix Electronics and suitable for LED display drivers, microcontroller I/O expanders, industrial serial data converters, and legacy bus interface adapters requiring stable component supply and long-term manufacturability.

Supply support for M74HC166RM13TR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with vertical manufacturing and broad analog/mixed-signal portfolio.

The M74HC166RM13TR belongs to ST's high-speed HC logic family, designed for pin-compatible upgrades of legacy 74-series TTL devices in industrial control, instrumentation, and embedded interface applications.

FAQ

Can M74HC166RM13TR operate reliably at 3.3 V?

Yes. The device is fully specified from 2 V to 6 V, with guaranteed VIH = 2.31 V and VIL = 0.99 V at VCC = 3.3 V (interpolated per datasheet curves), and delivers 45 MHz fMAX and ±4 mA drive - meeting all requirements for 3.3 V LVTTL and mixed-voltage system interfacing.

What is the minimum pulse width required for CLEAR?

The minimum CLEAR pulse width is 5 ns at VCC = 6 V (per AC specs), and 19 ns at VCC = 4.5 V. This ensures reliable asynchronous reset even in high-speed clock domains, provided the pulse meets tW(L) spec and is asserted before any clock edge affecting state retention.

Does SHIFT/LOAD require debouncing in mechanical switch applications?

No. The input has standard CMOS threshold and hysteresis is not specified, but with 28% VCC noise immunity and typical 13 ns setup time, a simple RC filter (e.g., 10 kΩ + 100 pF) suffices for pushbutton use - no active debouncing circuit needed for most industrial panel interfaces.

Is the TSSOP-16 package compatible with reflow soldering per JEDEC J-STD-020?

Yes. The M74HC166RM13TR TSSOP package is qualified for standard Pb-free reflow profiles, with peak temperature rating of 260 °C (10 sec max), MSL level 1, and thermal resistance θJA = 125 °C/W - fully compliant with JEDEC J-STD-020D for automated assembly.