Texas Instruments CD54HC40105F3A

Overview

CD54HC40105F3A from Texas Instruments is a high-speed CMOS 4-bit × 16-word first-in-first-out (FIFO) elastic storage register with independent asynchronous input/output control, three-state outputs, and master reset functionality. It operates from 2V to 6V, supports -55°C to +125°C, and delivers ripple-through delay of 400 ns (typ) at 4.5V for SI-to-Qn - enabling reliable buffering between mismatched clock domains in radar data acquisition and CPU/terminal interfaces.

For engineers reviewing the CD54HC40105F3A datasheet, CD54HC40105F3A pinout, CD54HC40105F3A application, or CD54HC40105F3A equivalent, this page provides verified functional specifications, CERDIP package details, timing behavior under military temperature range, and validated alternatives for FIFO-based system synchronization.

Technical Context

The CD54HC40105F3A implements a marker-bit–based control logic architecture where each of 16 positions contains a flip-flop that tracks data validity; "1" = filled, "0" = vacant. Data propagation occurs via ripple-triggered clock pulses generated when a "0" position detects a preceding "1", eliminating need for global clock distribution.

Its shift-out (SO) signal operates independently of three-state output enable (OE), unlike CD40105B - allowing safe concurrent bus release and data shifting. Status flags DATA-IN READY (DIR) and DATA-OUT READY (DOR) provide real-time full/empty indication without external logic.

Key Specifications

Pinout & Package

CD54HC40105F3A is supplied in a 16-lead Ceramic Dual In-line Package (CERDIP), hermetically sealed for high-reliability operation in extended temperature and radiation-prone environments. Pin numbering follows standard DIP convention with Pin 1 in top-left corner when notch faces upward.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC40105E and CD54HCT40105F3A, CD54HC40105F3A uniquely combines military-grade CERDIP packaging, 2V–6V universal supply support, and CMOS input thresholds - making it the sole choice for high-reliability, multi-voltage, radiation-tolerant FIFO buffering.

Availability

CD54HC40105F3A is available at Aetrix Electronics and suitable for radar data acquisition, avionics subsystems, and downhole instrumentation requiring stable component supply across extreme temperature cycles and long product lifecycles.

Supply support for CD54HC40105F3A 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 high-reliability logic solutions, with decades of heritage in military-grade IC development.

The CD54HC40105F3A belongs to TI's CD54HC high-speed CMOS logic family, engineered specifically for demanding aerospace, defense, and industrial applications requiring guaranteed operation across -55°C to +125°C with hermetic packaging.

FAQ

What is the maximum operating frequency of CD54HC40105F3A at 4.5V?

The CD54HC40105F3A supports a maximum SI or SO pulse frequency of 12 MHz over the full -55°C to +125°C range at VCC = 4.5V, as specified in the switching characteristics table. This limit ensures reliable marker-bit propagation and data transfer integrity across the entire military temperature envelope. The CD54HC40105F3A achieves this performance while maintaining 400 ns typical SI-to-Qn delay and 600 ns SI-to-DOR ripple-through time.

Does CD54HC40105F3A require external pull-up resistors on DIR and DOR pins?

Yes, CD54HC40105F3A features open-drain DIR and DOR outputs, requiring external pull-up resistors to VCC for proper HIGH-level assertion. Typical values range from 4.7 kΩ to 10 kΩ depending on bus capacitance and rise-time requirements. These status flags indicate FIFO full (DIR LOW) and empty (DOR LOW) conditions, and their correct logic levels are essential for handshake-driven data flow control in systems using the CD54HC40105F3A.

How does the master reset (MR) affect stored data in CD54HC40105F3A?

The MR input on CD54HC40105F3A resets only the internal marker-bit control flip-flops to "0", declaring all 16 positions vacant without altering the actual data latched in D0–D3 registers. This means previously loaded words remain physically present but are marked invalid and will be overwritten on the next SI pulse. The CD54HC40105F3A thus supports non-destructive reset for fault recovery while preserving transient data integrity.

Can CD54HC40105F3A be cascaded to increase FIFO depth beyond 16 words?

Yes, CD54HC40105F3A supports depth expansion by connecting DIR of one device to SO of the next, and DOR of the first to SI of the second - forming a daisy-chained FIFO array. A master reset pulse must be applied after power-up to synchronize all stages. This configuration maintains full 4-bit width while extending storage capacity in 16-word increments, enabling scalable buffering in systems like multi-channel radar receivers using the CD54HC40105F3A.

What is the purpose of the three-state output enable (OE) pin on CD54HC40105F3A?

The OE pin on CD54HC40105F3A controls the high-impedance state of Q0–Q3 outputs: when OE is LOW, outputs are disabled and electrically isolated from the data bus; when OE is HIGH, outputs actively drive valid data. Critically, OE has no effect on SO or shift operations - the CD54HC40105F3A continues advancing its internal pointer and updating DIR/DOR flags regardless of OE state, enabling robust bus sharing in multi-master systems.