Texas Instruments CD74HCT670MTE4

Overview

CD74HCT670MTE4 from Texas Instruments is a 4-word × 4-bit high-speed CMOS register file with independent simultaneous read/write capability, three-state outputs, buffered inputs, and operation across -55°C to +125°C. It supports 4.5V–5.5V supply, exhibits 17ns typical propagation delay (CL = 15pF), and enables expandable memory architectures up to 512 words in industrial control and test equipment.

For engineers reviewing the CD74HCT670MTE4 datasheet, CD74HCT670MTE4 pinout, CD74HCT670MTE4 application, or CD74HCT670MTE4 equivalent, key selection criteria include simultaneous read/write timing, HCT-level TTL input compatibility (VIH ≥ 2.0V, VIL ≤ 0.8V), three-state bus interface behavior, and SOIC-16 thermal performance (θJA = 73°C/W).

Technical Context

The CD74HCT670MTE4 implements a synchronous register file architecture with separate write address (WA0/WA1) and read address (RA0/RA1) decoders, enabling concurrent access to distinct 4-bit locations. Its dual enable logic (WE low for write, RE low for read) ensures deterministic data capture and output gating without internal clocking.

All inputs are buffered CMOS with HCT-specific input thresholds, and outputs drive LSTTL loads (15 per bus driver) while maintaining high noise immunity (NIL/NIH = 30% of VCC). The device operates exclusively in static mode-no internal clocks or state machines-and relies on external timing control for setup/hold compliance (tSU = 18ns, tH = 5ns at VCC = 4.5V).

Key Specifications

Pinout & Package

CD74HCT670MTE4 is housed in a 16-pin SOIC (D) package with 1.27 mm pitch, 10.3 mm body width, and moisture sensitivity level 1 (260°C peak reflow). Pin 1 is located in quadrant Q1 per tape-and-reel orientation standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC670MTE4, the CD74HCT670MTE4 offers tighter TTL-compatible input thresholds and lower power at 5V, while SN74ACT670N delivers superior speed and drive strength but with higher ICC and no extended temperature qualification beyond 85°C.

Availability

CD74HCT670MTE4 is available at Aetrix Electronics and suitable for automated test equipment, digital logic analyzers, industrial PLC I/O modules, and aerospace avionics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HCT670MTE4 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 heritage in high-reliability industrial and aerospace components.

The CD74HCT670MTE4 belongs to TI's legacy High-Speed CMOS Logic (HCT) register file product line, designed specifically for deterministic, low-latency data buffering in mixed-technology digital systems requiring TTL compatibility and wide temperature operation.

FAQ

What is the maximum operating frequency supported by the CD74HCT670MTE4?

The CD74HCT670MTE4 does not have a specified maximum clock frequency because it is a static register file with no internal clock. Its usable toggle rate depends on external timing: with tSU = 18ns and tH = 5ns at VCC = 4.5V, sustained read/write cycles can exceed 20 MHz when controlled by properly timed enable signals. The 17ns typical propagation delay (CL = 15pF) sets the lower bound on address-to-output latency.

Can the CD74HCT670MTE4 be used with a 3.3V microcontroller interface?

No, the CD74HCT670MTE4 requires a 4.5V–5.5V supply and is not 3.3V compatible. Its HCT inputs demand VIH ≥ 2.0V minimum, but 3.3V logic may not reliably meet this threshold across temperature and process variation. Direct interfacing risks undetected logic errors. Use level translators such as TXB0104 or discrete MOSFET buffers if connecting to 3.3V controllers.

How does the CD74HCT670MTE4 handle simultaneous read and write to the same address?

When WA0/WA1 and RA0/RA1 select the same 4-bit location, the CD74HCT670MTE4 outputs reflect the previously stored value until the write completes. Because write latching occurs on the WE falling edge and read access is combinatorial, the output shows old data during the write transition. No bus contention or undefined state occurs-the device maintains functional integrity per its truth table.

Is the CD74HCT670MTE4 pin-compatible with the CD74HC670MTE4?

Yes, the CD74HCT670MTE4 and CD74HC670MTE4 share identical SOIC-16 pinouts, terminal functions, and package dimensions. However, they differ electrically: CD74HC670MTE4 supports 2V–6V operation and HC input thresholds, while CD74HCT670MTE4 is restricted to 4.5V–5.5V with TTL-compatible inputs. Swapping requires verifying supply voltage and driving logic family compatibility.

What thermal derating applies to the CD74HCT670MTE4 in a 73°C/W SOIC package?

With θJA = 73°C/W and maximum junction temperature of 150°C, the CD74HCT670MTE4 must limit power dissipation to ≤1.03 W in still-air conditions at 25°C ambient. At 85°C ambient, allowable power drops to 0.9 W. For continuous operation above 100°C board temperature, forced airflow or thermal vias under the package are recommended to maintain junction temperature within specification.