Texas Instruments 7704201FA

Overview

7704201FA from Texas Instruments is a military-grade 4×4 register file IC with three-state outputs, implemented in TTL-LS logic. It provides 16-bit storage (four 4-bit words), supports independent read/write addressing via A0–A1 inputs, and features high-impedance output control via OE. Used in legacy aerospace data path buffering and microcoded controller register stacks.

For engineers reviewing the 7704201FA datasheet, 7704201FA pinout, 7704201FA application, or 7704201FA equivalent, key selection criteria include military temperature range (–55°C to +125°C), CFP ceramic flatpack package integrity, 3-state bus interface capability, and compatibility with 5-V TTL systems requiring deterministic register-file access timing.

Technical Context

The 7704201FA implements a synchronous 4-word × 4-bit random-access register file using bipolar TTL-LS circuitry. Address decoding is static, with separate A0/A1 inputs selecting one of four 4-bit registers for simultaneous read or write operations. Write enable (WE) and output enable (OE) are active-low, asynchronous controls that operate independently of clocking - no internal clock signal is required.

Read and write cycles are non-overlapping and edge-triggered only by control signal transitions. Data retention is static (no refresh), and outputs drive standard TTL loads directly. The device operates exclusively from a single +5 V supply with typical ICC of 110 mA at 5 V and 25°C.

Key Specifications

Pinout & Package

7704201FA is housed in a 16-pin ceramic flatpack (CFP) package per TI package drawing W, with hermetic sealing and gold-plated leads suitable for high-reliability mil-aero applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SNJ54LS670W (identical function and package) and 7704201EA (same die in CDIP), the 7704201FA offers guaranteed hermeticity and full military temp range in CFP - essential for flight-critical register storage where long-term parameter stability under thermal cycling is non-negotiable.

Availability

7704201FA is available at Aetrix Electronics and suitable for avionics data buffering, microcoded controller register stacks, and spacecraft onboard computer memory requiring stable component supply across extended production lifecycles and obsolescence-prone legacy programs.

Supply support for 7704201FA 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and high-reliability logic solutions for industrial, automotive, and defense markets.

The SN54LS670 family was designed specifically for military and aerospace systems requiring deterministic, clockless register storage with guaranteed operation across extreme temperature and radiation environments.

FAQ

What is the operating voltage range for the 7704201FA?

The 7704201FA operates strictly at +5 V ±5%, per its TTL-LS logic design. It does not support wide-input voltage rails or dual-supply operation. Deviation beyond ±5% risks incorrect logic thresholds, increased power dissipation, or latch-up. All designs must use a tightly regulated 5-V source with local 0.1 µF ceramic decoupling at the VCC pin. The 7704201FA datasheet specifies no tolerance relaxation for temperature or aging effects.

Does the 7704201FA require a clock signal to function?

No, the 7704201FA is fully asynchronous - it has no clock input. Register access is controlled solely by transitions on WE (write enable) and OE (output enable), with address inputs A0/A1 selecting the target word. This eliminates clock tree design, skew management, and jitter sensitivity. The 7704201FA's 45 ns access time is guaranteed from control signal edges, making it ideal for timing-critical, clockless datapaths in legacy systems.

How many registers does the 7704201FA provide, and what is their width?

The 7704201FA provides exactly four independent 4-bit registers, forming a 4×4 register file totaling 16 bits of storage. Each register is individually addressable via the 2-bit A0/A1 bus, and all four registers retain data statically without refresh. The 7704201FA does not support byte-wide or partial-word access - reads and writes always affect all four bits of the selected register simultaneously.

What is the meaning of "NC" pins on the 7704201FA pinout?

Pins 8–13 on the 7704201FA are designated No Connect (NC) - they have no internal connection to the silicon die and must remain unconnected in PCB layout. TI explicitly prohibits routing traces to or placing vias under these pins. Doing so may cause parasitic coupling, violate hermetic seal integrity, or induce latch-up. The 7704201FA CFP package uses these positions for mechanical symmetry and thermal balance, not functionality.

Is the 7704201FA RoHS-compliant?

The 7704201FA is not RoHS-compliant. As a military-qualified CFP device manufactured prior to RoHS enforcement, it contains lead in solder and finish per exemption 7a (high-melting-temperature solders). TI's packaging addendum confirms "TBD" for Eco Plan and "Call TI" for lead finish - indicating legacy Pb-based termination. For RoHS-compliant alternatives, consider modern SOIC-packaged SN74LS670D, though it lacks military temperature rating and hermeticity.