NXP Semiconductors 74HC670DB,118

Overview

74HC670DB,118 from NXP Semiconductors is a 4 × 4-bit 3-state register file IC with independent read/write address inputs (RA/RB and WA/WB), dual enable controls (RE/WE), and true non-inverting outputs (Q0–Q3). It supports simultaneous read-from-one-location and write-to-another-location operations, operates at 2–6 V supply, and delivers 23 ns D→Q propagation delay at 5 V with 15 pF load.

For engineers reviewing the 74HC670DB,118 datasheet, 74HC670DB,118 pinout, 74HC670DB,118 application, or 74HC670DB,118 equivalent, key selection considerations include its 16-pin SSOP package, bus-driver output capability, simultaneous read/write architecture, and compatibility with 74HCT670 for TTL-level interfacing in legacy logic systems.

Technical Context

The 74HC670DB,118 implements a synchronous 4-word × 4-bit register file using high-speed Si-gate CMOS technology. Its dual address buses (RA/RB for read, WA/WB for write) and separate RE/WE enables allow concurrent access without internal arbitration or clocking-no external clock required. All timing is edge-triggered on enable transitions, with latch transparency during active WE.

It features true 3-state outputs with enable-controlled high-impedance OFF-state (Z), enabling direct bus-tie expansion. The device meets JEDEC Standard No. 7A and is pin-compatible with LSTTL, supporting mixed-voltage system integration via its 2–6 V VCC range and HCT-compatible input thresholds when used in 74HCT670 mode.

Key Specifications

Pinout & Package

74HC670DB,118 is housed in a 16-pin small shrink outline package (SSOP), measuring 4.4 mm × 5.0 mm with 0.65 mm lead pitch and gull-wing leads. This surface-mount package supports automated assembly and provides thermal and mechanical reliability for industrial control logic.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC670DB,118, the 74HCT670DB,118 offers guaranteed TTL-level input compatibility without sacrificing speed or package size, while the SN74ALS670N trades power efficiency and modern packaging for backward mechanical fit in obsolete sockets - making the HC variant optimal for new low-power, surface-mount logic designs.

Availability

74HC670DB,118 is available at Aetrix Electronics and suitable for industrial PLC register stacks, microprocessor bus interfaces, digital signal path sequencing, and legacy TTL system upgrades requiring stable component supply and long-term obsolescence management.

Supply support for 74HC670DB,118 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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Philips' pioneering logic IC development.

The 74HC670DB,118 belongs to the 74HC/HCT logic family designed specifically for high-speed, low-power CMOS replacement of TTL in general-purpose digital systems - emphasizing pin compatibility, predictable timing, and robust bus-driving capability.

FAQ

What is the supply voltage range supported by the 74HC670DB,118?

The 74HC670DB,118 operates over a VCC range of 2.0 V to 6.0 V, enabling use in both low-voltage portable systems and standard 5 V logic environments. Its CMOS design ensures stable operation across this full range without level-shifting circuitry, and all AC parameters-including 23 ns D→Q propagation delay-are specified at 5 V with 15 pF load. This wide supply tolerance makes the 74HC670DB,118 suitable for mixed-rail designs where other logic may run at 3.3 V or 5 V.

Does the 74HC670DB,118 require an external clock signal?

No, the 74HC670DB,118 does not require an external clock. It is an asynchronous register file controlled solely by enable and address inputs: WE (write enable) and RE (read enable) trigger transparent latching and 3-state output control on their active-LOW transitions. Data is latched when WE goes LOW while WA/WB addresses are stable, and outputs appear immediately when RE goes LOW with valid RA/RB. This eliminates clock distribution complexity in simple state-holding or buffering applications.

How many registers and bits per register does the 74HC670DB,118 provide?

The 74HC670DB,118 provides exactly four 4-bit registers, totaling 16 bits of storage organized as a 4 × 4 register file. Each register is individually addressable: WA/WB select the write location (00 to 11), and RA/RB independently select the read location. This architecture enables true simultaneous read and write operations-e.g., reading from register 2 while writing to register 0-without conflict or arbitration logic, a key differentiator from single-port RAMs.

Can multiple 74HC670DB,118 devices be connected to the same data bus?

Yes, multiple 74HC670DB,118 devices can share a common data bus because each has true 3-state outputs controlled by the RE input. When RE is HIGH, Q0–Q3 enter high-impedance (Z) state, electrically disconnecting that device from the bus. Proper system design requires ensuring only one device has RE = LOW at any time to prevent bus contention. This capability enables straightforward word-width expansion-for example, eight 74HC670DB,118 units yield a 4 × 32-bit register file with parallel address and enable lines.

What is the meaning of "MSI" listed in the 74HC670DB,118 ICC category?

"MSI" stands for Medium-Scale Integration, indicating the 74HC670DB,118 contains approximately 100–999 logic gates-consistent with its 16-bit register file, dual 2-bit address decoders, four 3-state output drivers, and associated control logic. This classification distinguishes it from SSI (e.g., single gates) and LSI (e.g., microcontrollers), positioning the 74HC670DB,118 as a structured building block for custom data-path logic rather than a general-purpose processor or memory. Its MSI density balances functionality with testability and predictable timing behavior.