Texas Instruments CD54HCT164F3A

Overview

CD54HCT164F3A from Texas Instruments is a military-grade 8-bit serial-in, parallel-out shift register with asynchronous reset, operating at 4.5V–5.5V, supporting up to 54 MHz clock frequency (CL = 15 pF), featuring dual serial data inputs (A/B) for data enable control, and rated for –55°C to +125°C operation in ceramic DIP-14 package. It serves in high-reliability timing and data serialization circuits within avionics and defense systems.

For engineers reviewing the CD54HCT164F3A datasheet, CD54HCT164F3A pinout, CD54HCT164F3A application, or CD54HCT164F3A equivalent, key selection criteria include its TTL-compatible input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V), guaranteed propagation delay (tPLH/tPHL ≤ 54 ns max at –55°C to +125°C), and hermetic CDIP packaging for extended temperature and radiation-tolerant environments.

Technical Context

The CD54HCT164F3A implements a positive-edge-triggered shift register architecture with fully asynchronous active-low reset (CLR), enabling immediate output clearing independent of clock state. Its dual serial inputs (A and B) support OR-gated data enable logic-either input asserted high enables serial data flow on CLK rising edge.

Designed for military applications, it uses HCT logic family characteristics: LSTTL-input compatible voltage levels, CMOS power efficiency (ICC ≤ 160 μA over full temp range), and robust noise immunity (NIL/NIH = 30% of VCC at 5 V). All outputs drive 10 LSTTL loads across the full temperature range.

Key Specifications

Pinout & Package

Ceramic Dual-In-Line Package (CDIP-14), 19.55 mm × 6.71 mm body size, hermetically sealed with glass-frit lid per MIL-STD-1835 GDIP1-T14. Pin 1 identified by index mark on cap; seating plane defined per JEDEC MS-012 AB variant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit serial-in, parallel-out shift register applications.

Compared with CD74HCT164E and SN74HCT164N, the CD54HCT164F3A uniquely combines hermetic ceramic packaging, QML-38534 Class V qualification, and guaranteed performance across –55°C to +125°C - making it the sole option for mission-critical aerospace and defense timing subsystems requiring zero moisture permeability and radiation tolerance.

Availability

CD54HCT164F3A is available at Aetrix Electronics and suitable for avionics display controllers, military radar timing modules, secure crypto key loaders, and downhole telemetry interfaces requiring stable component supply under extended temperature and high-reliability conditions.

Supply support for CD54HCT164F3A 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 specializing in analog, embedded processing, and high-reliability logic solutions for industrial, automotive, and defense markets.

The CD54HCT164F3A belongs to TI's military-grade HCT logic family, engineered specifically for high-integrity serial-to-parallel data conversion in safety-critical systems operating under extreme thermal and environmental stress.

FAQ

What is the maximum clock frequency supported by the CD54HCT164F3A?

The CD54HCT164F3A supports a maximum clock frequency of 54 MHz under specified conditions: VCC = 5 V, CL = 15 pF, and TA = 25°C. At full military temperature range (–55°C to +125°C), the guaranteed fMAX is 18 MHz per switching characteristics table. This rating ensures reliable shift operation in real-time avionics and radar timing applications where deterministic latency is mandatory. The CD54HCT164F3A achieves this using optimized HCT gate design with balanced rise/fall times.

Does the CD54HCT164F3A require external pull-up or pull-down resistors on unused inputs?

Yes, the CD54HCT164F3A requires all unused inputs-including A, B, and CLR-to be tied to a valid logic level (VCC or GND) per TI layout guidelines. Floating inputs can cause undefined output states, increased ICC, or oscillation due to internal input stage metastability. For example, an unconnected CLR pin may inadvertently trigger reset events. TI specifies that unused inputs must be terminated to meet VIH/VIL thresholds; tying A and B to GND disables serial data flow, while CLR pulled high ensures normal operation.

How does the dual serial input (A and B) functionality work in the CD54HCT164F3A?

The CD54HCT164F3A implements OR logic between Pins 1 (A) and 2 (B): data shifts into QA on the rising edge of CLK only when at least one of A or B is HIGH. If both are LOW, no data is loaded regardless of CLK. This allows flexible data enable control-e.g., A driven by microcontroller GPIO and B by hardware handshake signal. The truth table confirms that QA updates only when CLR = HIGH and (A = HIGH or B = HIGH). This eliminates need for external OR gates in systems requiring multi-source serial data routing.

Is the CD54HCT164F3A pin-compatible with the CD74HCT164 series?

Yes, the CD54HCT164F3A is pin-compatible with CD74HCT164E and CD74HCT164M in the same package variants (e.g., CDIP-14 or PDIP-14), sharing identical pin numbering, function mapping, and electrical interface. However, CD54HCT164F3A differs in qualification: it is QML-38534 Class V certified with hermetic ceramic packaging, whereas CD74HCT164E uses plastic DIP and lacks military screening. Electrical specs match at 25°C, but CD54HCT164F3A guarantees performance across –55°C to +125°C with tighter AC limits.

What is the purpose of the CLR (Pin 5) signal, and how does it interact with clock operation?

The CLR (Pin 5) is an asynchronous, active-low reset that forces all parallel outputs (QA–QH) LOW immediately-regardless of CLK state or data inputs. When CLR = LOW, the shift register contents are cleared and outputs remain LOW until CLR returns HIGH. Only after CLR goes HIGH does the device resume normal shift operation on subsequent CLK rising edges. This behavior is confirmed in the truth table and functional description. In CD54HCT164F3A-based systems, CLR is commonly tied to power-on reset circuits or watchdog timers to ensure known initial state before data loading begins.