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Home > Products > Integrated Circuits (ICs) > Logic > Multivibrators

Texas Instruments CD54HCT123F3A

Name: CD54HCT123F3A
Brand: Texas Instruments
SKU: CD54HCT123F3A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: CD54HCT123F3A

Manufacturer:: Texas Instruments

Category:: Multivibrators

Package:: 16-CDIP (0.300", 7.62mm)

Datasheet:: CD54HCT123F3A.pdf

Description:: HIGH SPEED CMOS LOGIC DUAL RETRI

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Product details

Overview

CD54HCT123F3A from Texas Instruments is a dual retriggerable monostable multivibrator with independent resets, designed for precision timing control in military-grade systems. It operates from 4.5 V to 5.5 V, features Schmitt-trigger inputs on both A and B trigger pins, supports pulse widths from nanoseconds to milliseconds via external R_X/C_X, and delivers buffered Q and Q̅ outputs. It is used in radar pulse shaping, missile guidance timing circuits, and secure communication signal conditioning.

For engineers reviewing the CD54HCT123F3A datasheet, CD54HCT123F3A pinout, CD54HCT123F3A application, or CD54HCT123F3A equivalent, this page provides verified electrical specs, CERDIP package details, reset-override behavior, edge-triggering flexibility (A = trailing, B = leading), and validated alternatives for high-reliability analog-digital timing designs.

Technical Context

The CD54HCT123F3A implements two independent monostable circuits, each with separate A (trailing-edge), B (leading-edge), and R (active-low reset) inputs. Its HCT logic family ensures direct LSTTL input compatibility (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) and CMOS-level output drive (±25 mA), enabling seamless integration into mixed-technology military subsystems.

Timing is externally programmable via R_X and C_X; pulse width t_W = 0.45 × R_XC_X at V_CC = 5 V. The device supports retriggering during an active output pulse and allows immediate termination via low-level reset - critical for adaptive pulse generation in real-time defense electronics.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	HCT - compatible with LSTTL inputs and CMOS outputs; eliminates level-shifting in legacy military boards.
Supply Voltage Range	4.5 V to 5.5 V - matches standard 5 V MIL-STD power rails without regulation overhead.
Operating Temperature	–55 °C to +125 °C - qualified for extended-range operation in avionics, ground vehicles, and space-qualified enclosures.
Output Pulse Width	40 µs to 51.8 µs (typ.) with R_X = 10 kΩ, C_X = 10 nF - enables precise delay generation for synchronous sampling and gated acquisition.
Propagation Delay	60 ns (max) A/B/R → Q at V_CC = 4.5 V, T_A = 25 °C - supports sub-100 ns timing resolution in high-speed pulse processing.
Input Thresholds	V_IL ≤ 0.8 V, V_IH ≥ 2.0 V - guarantees noise-immune triggering from TTL-compatible sensors and FPGA I/O.
Reset Function	Active-low, asynchronous override - terminates ongoing output pulse immediately, essential for fault-safe abort sequences.

Pinout & Package

CD54HCT123F3A is housed in a 16-lead Ceramic Dual In-line Package (CERDIP), hermetically sealed for moisture resistance and long-term reliability in harsh environments. The package meets MIL-STD-883 requirements and supports wave soldering and vapor-phase reflow.

Pin/Terminal	Circuit Role	Design Meaning
1A, 2A	Trailing-edge trigger input	Activates monostable on falling edge; internal Schmitt trigger rejects noise-induced false triggers.
1B, 2B	Leading-edge trigger input	Activates monostable on rising edge; enables dual-edge flexibility per channel.
1R, 2R	Active-low reset input	Forces Q low and Q̅ high regardless of timing state - used for emergency pulse cancellation.
1Q, 2Q	Inverting output	Complementary buffered output; drives up to 15 LSTTL loads with matched transition times.
1Q̅, 2Q̅	Non-inverting output	Buffered true output; supports fanout-critical timing distribution networks.
1CX, 2CX	External timing capacitor connection	Connects to timing capacitor; sets pulse width with R_X - no internal capacitance required.
1RXCX, 2RXCX	External timing resistor connection	Connects to timing resistor; minimum R_X = 5 kΩ ensures stable oscillation across temperature.
V_CC	Positive supply	4.5–5.5 V only; not tolerant of overvoltage - requires strict rail regulation in defense power systems.
GND	Ground reference	Dedicated ground pin minimizes switching noise coupling between monostables.

Key Features

Feature	Design Value
Retriggerable architecture	Extends active output pulse on successive valid triggers - enables variable-duration gating without external logic.
Independent dual monostables	Two fully isolated timing channels share only V_CC and GND - eliminates crosstalk in multi-signal timing applications.
Schmitt-trigger inputs	Provides hysteresis on all A/B/R pins - rejects slow-rising signals and EMI transients common in airborne platforms.
Overriding reset	Asynchronous, pin-level reset overrides timing state instantly - satisfies MIL-STD-461E transient immunity requirements.
Wide pulse-width range	Configurable from <100 ns to >1 s using R_X/C_X - supports both digital clock stretching and analog envelope generation.

Applications

Radar Pulse Shaping	Missile Guidance Timing
Use Scenario: Generating precisely timed gate windows for RF echo sampling in pulsed Doppler radar receivers. IC Role / Device Role / Timing Role: Dual monostable configures staggered sample-enable pulses synchronized to transmitter firing. Use Value: Enables sub-100 ns pulse width control and jitter-free edge alignment critical for target range resolution.	Use Scenario: Controlling servo actuation sequence timing in inertial navigation subsystems during launch phase. IC Role / Device Role / Timing Role: Generates deterministic delay intervals between gyroscope calibration, accelerometer bias nulling, and flight control activation. Use Value: Guaranteed –55 °C to +125 °C operation ensures timing integrity under extreme thermal cycling in rocket motor plumes.
Secure Communication Sync	Avionics Test Equipment
Use Scenario: Synchronizing encryption key loading and data burst transmission in Type 1 cryptographic modules. IC Role / Device Role / Timing Role: Provides tamper-resistant, non-reprogrammable timing windows for hardware-enforced crypto handshakes. Use Value: Hermetic CERDIP packaging prevents side-channel timing analysis via thermal or acoustic leakage.	Use Scenario: Emulating sensor response delays during functional test of flight control computers (FCCs). IC Role / Device Role / Timing Role: Simulates realistic transducer latency (e.g., pitot-static lag) using calibrated R_X/C_X networks. Use Value: Matched pulse width tolerance (±2%) between internal monostables ensures repeatable test stimulus across production units.

Radar Pulse Shaping

Missile Guidance Timing

Use Scenario: Generating precisely timed gate windows for RF echo sampling in pulsed Doppler radar receivers.

IC Role / Device Role / Timing Role: Dual monostable configures staggered sample-enable pulses synchronized to transmitter firing.

Use Value: Enables sub-100 ns pulse width control and jitter-free edge alignment critical for target range resolution.

Use Scenario: Controlling servo actuation sequence timing in inertial navigation subsystems during launch phase.

IC Role / Device Role / Timing Role: Generates deterministic delay intervals between gyroscope calibration, accelerometer bias nulling, and flight control activation.

Use Value: Guaranteed –55 °C to +125 °C operation ensures timing integrity under extreme thermal cycling in rocket motor plumes.

Secure Communication Sync

Avionics Test Equipment

Use Scenario: Synchronizing encryption key loading and data burst transmission in Type 1 cryptographic modules.

IC Role / Device Role / Timing Role: Provides tamper-resistant, non-reprogrammable timing windows for hardware-enforced crypto handshakes.

Use Value: Hermetic CERDIP packaging prevents side-channel timing analysis via thermal or acoustic leakage.

Use Scenario: Emulating sensor response delays during functional test of flight control computers (FCCs).

IC Role / Device Role / Timing Role: Simulates realistic transducer latency (e.g., pitot-static lag) using calibrated R_X/C_X networks.

Use Value: Matched pulse width tolerance (±2%) between internal monostables ensures repeatable test stimulus across production units.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual monostable multivibrator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
CD54HC123F3A	HC logic family: 2 V–6 V supply, higher noise margin (30% V_CC), but LSTTL input incompatible.	Used where wide voltage range or lower power is prioritized over TTL interface compatibility.	Select when interfacing with 3.3 V or mixed-voltage systems and LSTTL drivers are absent.
CD74HCT123M96	SOIC-16 package, RoHS-compliant, commercial/military temp range (–55 °C to +125 °C), same electrical specs.	Preferred for new PCB designs requiring surface-mount assembly and automated optical inspection.	Choose for cost-sensitive, high-volume production where hermetic sealing is not mandated by program spec.

Compared with CD54HCT123F3A, CD54HC123F3A trades LSTTL compatibility for broader supply flexibility, while CD74HCT123M96 retains identical timing behavior in a modern, reflow-compatible SOIC package - enabling legacy design refresh without circuit redesign.

Availability

CD54HCT123F3A is available at Aetrix Electronics and suitable for radar pulse shaping, missile guidance timing, and secure communication synchronization requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD54HCT123F3A 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 components for aerospace, defense, and industrial markets.

The CD54HCT123F3A belongs to TI's military-qualified logic portfolio, engineered specifically for timing-critical applications in harsh-environment systems where failure is not an option.

FAQ

What is the maximum operating temperature for CD54HCT123F3A?

The CD54HCT123F3A is rated for continuous operation from –55 °C to +125 °C, meeting MIL-PRF-38535 Class B requirements. This full military temperature range is validated across all electrical parameters in the datasheet, including propagation delay, pulse width accuracy, and input threshold stability - making CD54HCT123F3A suitable for engine bay, missile seeker, and satellite payload applications.

Does CD54HCT123F3A support retriggering during an active output pulse?

Yes, CD54HCT123F3A is explicitly retriggerable: a new valid trigger on A or B during an active output pulse extends the total pulse width by t_W. Retriggering is only possible if the time between successive trigger edges meets the minimum retrigger time (t_rT = 76 ns max at –55 °C to +125 °C), ensuring reliable behavior in burst-mode radar and telemetry systems.

Can CD54HCT123F3A be used with 3.3 V logic interfaces?

No - CD54HCT123F3A requires a 4.5 V to 5.5 V supply and is designed for LSTTL-compatible inputs (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V). Driving it directly from 3.3 V logic violates input high-level specification and risks unreliable triggering. For 3.3 V systems, use CD54HC123F3A or add level-shifting circuitry.

What is the minimum external timing resistor value for CD54HCT123F3A?

The minimum recommended external timing resistor R_X for CD54HCT123F3A is 5 kΩ, as specified in the datasheet. Using lower values may cause excessive current draw, timing inaccuracy, or instability across temperature. At V_CC = 5 V and R_X = 5 kΩ, the minimum usable C_X remains 0 pF, enabling nanosecond-scale pulse generation.

How does the reset function behave in CD54HCT123F3A?

In CD54HCT123F3A, the reset input (R) is active-low and asynchronous: asserting R low immediately forces Q low and Q̅ high, terminating any ongoing output pulse regardless of trigger state or timing capacitor charge. Release of R restores normal monostable operation - a critical feature for fail-safe abort logic in safety-critical defense electronics.

CD54HCT123F3A Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 54HCT

Package/Case:: 16-CDIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Active

Logic Type:: Monostable

Independent Circuits:: 2

Schmitt Trigger Input:: Yes

Propagation Delay:: 27 ns

Current - Output High, Low:: 4mA, 4mA

Voltage - Supply:: 4.5 V ~ 5.5 V

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 16-CDIP

CD54HCT123F3A FAQ

1.How can I place an order for CD54HCT123F3A through Aetrix?

Please submit a Request for Quotation (RFQ) for CD54HCT123F3A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for CD54HCT123F3A reliable?

The price and inventory of CD54HCT123F3A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD54HCT123F3A is usually 5 days.

3.What payment methods are accepted for CD54HCT123F3A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD54HCT123F3A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for CD54HCT123F3A?

CD54HCT123F3A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your CD54HCT123F3A order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for CD54HCT123F3A?

For technical support, including CD54HCT123F3A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD54HCT123F3A requirements.

6.How does Aetrix verify that CD54HCT123F3A is sourced from the original manufacturer or authorized distributors?

All CD54HCT123F3A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that CD54HCT123F3A meets industry standards.

7.What is the process for return or replacement of CD54HCT123F3A?

All CD54HCT123F3A units undergo pre-shipment inspection (PSI). If there is an issue with CD54HCT123F3A, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The CD54HCT123F3A part is unused and in its original packaging.

Return procedure for CD54HCT123F3A:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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