STMicroelectronics M74HC670M1R

Overview

M74HC670M1R from STMicroelectronics is a high-speed CMOS 4-word × 4-bit register file with 3-state outputs, designed for synchronous read/write data buffering in digital control and addressable memory expansion circuits. It operates from 2V to 6V, delivers 22 ns typical propagation delay at 6V, supports simultaneous read and write via independent address inputs (RA/RB, WA/WB), and features symmetrical 4 mA output drive capability.

For engineers reviewing the M74HC670M1R datasheet, M74HC670M1R pinout, M74HC670M1R application, or M74HC670M1R equivalent, key selection criteria include its 3-state output enable timing (tPZL/tPHZ ≤ 28 ns at 6V), latch-to-output delay consistency (tPLH ≅ tPHL), wide temperature range (–55°C to +125°C), and compatibility with legacy 74-series register file logic interfaces.

Technical Context

The M74HC670 implements a silicon-gate C2MOS-based 4×4 register array with fully independent read and write address decoders, enabling concurrent access to different words without bus contention. Its dual 2-bit address buses (RA/RB and WA/WB) select one of four 4-bit words per operation, while RE and WE control active-low read and write enables.

All inputs include ESD protection diodes, and outputs support high-impedance tri-state behavior with leakage < ±5 µA at VCC = 6V. Propagation delays are balanced across input-to-output paths (Dn→Qn, RA/RB→Qn, WE→Qn), ensuring deterministic timing in pipelined or multi-cycle register file architectures.

Key Specifications

Pinout & Package

SOP-16 package (SO-16, JEDEC MS-013AC, body width 3.9 mm, pitch 1.27 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC670N and SN74LV670ADW, the M74HC670M1R uniquely combines SOP-16 compactness, full 2–6 V operation, independent dual-address capability, and guaranteed 22 ns timing - making it the sole choice for space-constrained, mixed-voltage, and high-throughput register file implementations.

Availability

M74HC670M1R is available at Aetrix Electronics and suitable for industrial motion controllers, automotive engine control units, programmable logic interfaces, and legacy system emulation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HC670M1R 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 M74HC670 belongs to ST's high-speed HC logic family, engineered for drop-in replacement of legacy 74-series register files while delivering enhanced noise immunity, wider voltage range, and improved thermal stability for mission-critical embedded control.

FAQ

What is the maximum clock frequency supported by M74HC670M1R?

The M74HC670M1R does not use a clock signal; it is an asynchronous register file controlled by edge-triggered enable signals (WE, RE). Its usable maximum operating frequency depends on the minimum pulse width (tW(L) = 3 ns at 6V) and propagation delays (tPLH/tPHL ≤ 48 ns at 125°C), supporting effective read/write cycles up to approximately 12 MHz in worst-case thermal conditions.

Can M74HC670M1R be used with 3.3 V microcontrollers?

Yes - the M74HC670M1R operates reliably from 2.0 V to 6.0 V, with VIH = 1.8 V (min) and VIL = 0.5 V (max) at VCC = 3.3 V. Its 4 mA output drive can directly interface with 3.3 V CMOS inputs, and its 28% noise margin ensures robust operation in mixed-voltage systems without level shifters.

How many M74HC670M1R devices can be connected in parallel on a shared bus?

Up to 128 M74HC670M1R devices can share a common data bus due to their 3-state outputs. Each device requires individual RE control, but all Q1–Q4 outputs may be wired together. Total word capacity scales linearly: 128 × 4 words = 512 words, with bit-width extended by paralleling multiple devices (e.g., two for 8-bit words).

Is M74HC670M1R pin-compatible with the original 74670 series?

Yes - the M74HC670M1R is functionally and pin-compatible with the 74LS670 and 74S670, retaining identical pin assignments (D1–D4, Q1–Q4, RA/RB, WA/WB, RE, WE, VCC, GND) and logic behavior. Differences are electrical (CMOS vs. TTL levels) and parametric (lower power, higher speed, wider voltage range), not mechanical or functional.