Texas Instruments CD74HC670MT

Overview

CD74HC670MT from Texas Instruments is a high-speed CMOS 4×4 register file IC used for temporary data storage and parallel word access in digital control logic, microcontroller peripheral interfaces, and state-machine datapaths. It features simultaneous independent read/write operations, 16-bit capacity (4 words × 4 bits), three-state outputs, 2V–6V supply operation, and -55°C to +125°C operating temperature range.

For engineers reviewing the CD74HC670MT datasheet, CD74HC670MT pinout, CD74HC670MT application, or CD74HC670MT equivalent, this page delivers verified functional architecture, timing behavior under HC logic family constraints, SOIC-16 package interface details, and validated drop-in alternatives for industrial control and embedded system design.

Technical Context

The CD74HC670MT implements a synchronous dual-port register file with separate write address (WA0/WA1) and read address (RA0/RA1) inputs, enabling concurrent write-to-one-location and read-from-another without bus contention. Its internal latches retain data transparently during write enable (WE = L), while read enable (RE = L) gates output drivers to present addressed 4-bit word at Q0–Q3.

It operates strictly as a combinational+storage device - no clock input required - with propagation delays defined by VCC and load capacitance (e.g., 16ns typical read time at 5V/15pF). All inputs are buffered; outputs drive up to 10 LSTTL loads and support bus-tied expansion to 512×4-bit configurations via three-state control.

Key Specifications

Pinout & Package

CD74HC670MT is housed in a 16-pin Small Outline Integrated Circuit (SOIC) package with standard 1.27mm pitch, JEDEC MS-012AC compliant footprint, and moisture sensitivity level (MSL) 1 rating for lead-free reflow compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HCT670MT and SN74ACT670N, the CD74HC670MT provides the broadest supply range (2–6V), highest noise immunity (30% VCC), and lowest quiescent current (≤160µA), making it the preferred choice for battery-powered, mixed-signal, or extended-temperature embedded systems where voltage flexibility and EMI resilience are critical.

Availability

CD74HC670MT is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC670MT 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions with decades of high-reliability component development for aerospace, automotive, and industrial markets.

The CD74HC670MT belongs to TI's legacy High-Speed CMOS Logic (74HC) product line, designed specifically for low-power, high-noise-immunity register storage in deterministic digital control systems where clockless operation and voltage scalability are essential.

FAQ

What is the maximum clock frequency supported by CD74HC670MT?

The CD74HC670MT does not use a clock signal - it is an asynchronous register file. Its speed is governed by propagation delay and setup/hold timing. At VCC = 5V and CL = 15pF, typical read access is 16ns, supporting effective cycle rates up to ~50 MHz in tightly controlled layouts. Maximum reliable operation depends on address stability before WE/RE assertion and load capacitance.

Can CD74HC670MT operate at 3.3V supply voltage?

Yes, CD74HC670MT is fully specified for 2V–6V operation, including 3.3V. At 3.3V, VIH = 2.31V (min), VIL = 1.0V (max), and output drive remains compatible with 3.3V LVTTL and LVCMOS interfaces. Propagation delay increases slightly versus 5V (e.g., ~45ns max at CL = 50pF), but remains within functional timing budgets for most embedded control applications.

Is CD74HC670MT pin-compatible with CD74HCT670MT?

Yes, CD74HC670MT and CD74HCT670MT share identical SOIC-16 pinout, terminal functions, and mechanical footprint. The only differences are input threshold specifications (HC: 30% VCC; HCT: TTL-compatible) and recommended supply range (HC: 2–6V; HCT: 4.5–5.5V). No PCB changes are required when substituting between them, provided system voltage and noise environment align with each variant's electrical characteristics.

How many CD74HC670MT devices can be connected in parallel to expand word width?

CD74HC670MT supports bus-tied expansion to increase total word capacity - not word width. To expand from 4-bit to n-bit words, multiple CD74HC670MT units are connected in parallel with shared WA/RA/WE/RE lines and separate D/Q buses per bit position. For example, eight CD74HC670MTs yield a 4×32-bit register file. Word depth expansion to 512 words is achieved by decoding higher-order address bits externally.

Does CD74HC670MT require external pull-up or pull-down resistors on its control inputs?

No, CD74HC670MT has CMOS input structure with negligible leakage (<±1µA) and defined VIH/VIL thresholds - inputs must be actively driven to valid logic levels. Floating inputs are undefined and may cause increased ICC or metastability. External biasing is unnecessary and discouraged; proper PCB layout with short traces and solid ground return ensures reliable operation without added components.