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

Texas Instruments CD54HC123F3A

Name: CD54HC123F3A
Brand: Texas Instruments
SKU: CD54HC123F3A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: CD54HC123F3A

Manufacturer:: Texas Instruments

Category:: Multivibrators

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

Datasheet:: CD54HC123F3A.pdf

Description:: HIGH SPEED CMOS LOGIC DUAL RETRI

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Product details

Overview

CD54HC123F3A from Texas Instruments is a dual retriggerable monostable multivibrator with independent resets, designed for precision timing control in military-grade systems. It operates from 2V to 6V, features Schmitt-trigger inputs on both A and B trigger pins, supports output pulse widths from nanoseconds to milliseconds via external RX/CX networks, 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 CD54HC123F3A datasheet, CD54HC123F3A pinout, CD54HC123F3A application, or CD54HC123F3A equivalent, this page provides verified timing parameters, CERDIP package details, reset behavior, edge-triggering modes, and validated alternatives for high-reliability analog-digital hybrid designs operating from –55°C to +125°C.

Technical Context

The CD54HC123F3A implements two independent monostable multivibrators, each with separate A (trailing-edge), B (leading-edge), and R (active-low reset) inputs. Triggering is retriggerable: a new input edge during an active output pulse extends the pulse width. The reset input overrides and terminates the output pulse immediately, regardless of current state.

Timing is externally controlled by resistor RX and capacitor CX, with pulse width calculated as t_W = 0.45 × R_XC_X at V_CC = 5V. Minimum external R_X is 5 kΩ; C_X can be as low as 0 pF. Propagation delays range from 37 ns (V_CC = 6V, CL = 15 pF) to 450 ns (V_CC = 2V, CL = 50 pF), ensuring predictable response across voltage and temperature extremes.

Key Specifications

Parameter	Value and Actual Design Meaning
Function	Dual retriggerable monostable multivibrator with independent resets
Supply Voltage Range	2V to 6V - enables direct integration into mixed-voltage military subsystems without level-shifting
Operating Temperature	–55°C to +125°C - qualified for extended-range aerospace and defense platforms
Pulse Width Range	Configurable from ~10 ns to >10 ms using external RX/CX - supports both narrow trigger gating and long-duration enable signals
Input Type	Schmitt-trigger on A and B inputs - ensures noise-immune edge detection even with slow-rising or noisy waveforms
Output Drive	CMOS-compatible buffered Q/Q̅ - drives up to 10 LSTTL loads over full temperature range, enabling direct interface to legacy logic
Reset Behavior	Active-low asynchronous reset (R) - forces immediate Q = LOW / Q̅ = HIGH, overriding ongoing timing cycle

Pinout & Package

CD54HC123F3A is housed in a 16-lead Ceramic Dual In-line Package (CERDIP), hermetically sealed for high-reliability operation in harsh environments. The package meets MIL-STD-883 requirements and supports lead-free soldering with SNPB finish.

Pin/Terminal	Circuit Role	Design Meaning
1A, 2A	Trailing-edge trigger input	Activates monostable on falling edge; internal Schmitt trigger rejects noise below 30% V_CC
1B, 2B	Leading-edge trigger input	Activates monostable on rising edge; identical noise immunity and threshold behavior as A inputs
1R, 2R	Active-low reset input	Asynchronously forces Q = LOW and Q̅ = HIGH; overrides all timing states immediately
1Q, 2Q	True output	Buffered CMOS output; sinks/sours ±25 mA; fanout = 10 LSTTL loads over full temp range
1Q̅, 2Q̅	Inverted output	Complementary buffered output; matches Q timing within ±2% pulse width match between channels
1CX, 2CX	External timing capacitor connection	Connects to external C_X; minimum value = 0 pF; sets pulse width with R_X
1RXCX, 2RXCX	External timing resistor connection	Connects to external R_X; minimum value = 5 kΩ; defines timing constant with C_X
V_CC, GND	Power supply terminals	Single 2–6 V supply; decoupling required per MIL-PRF-38535 guidelines for CERDIP packages

Key Features

Feature	Design Value
Retriggerable operation	Enables dynamic pulse extension during active output - critical for variable-width pulse generation in servo control loops
Independent A/B edge selection	Allows one-shot triggering from either rising or falling edges without external inverters - reduces component count in signal-conditioning chains
Overriding reset	Guarantees deterministic termination of timing cycle - essential for fail-safe timing in safety-critical avionics
Wide V_CC range (2–6 V)	Supports direct interface to 3.3 V, 5 V, and legacy 2.5 V logic domains without voltage translation
High noise immunity (NIL/NIH = 30%)	Rejects EMI-induced glitches in radar front-ends and RF subsystems operating near transmitters

Applications

Radar Pulse Shaping	Missile Guidance Timing
Use Scenario: Generating precisely timed gate pulses to isolate RF return signals in pulsed Doppler radar receivers. IC Role / Device Role / Timing Role: Monostable multivibrator providing adjustable blanking intervals synchronized to transmitter pulses. Use Value: Enables rejection of near-field clutter via sub-microsecond pulse width control (t_W = 0.45·R_XC_X) with <±2% matching between dual channels.	Use Scenario: Controlling actuator enable windows in inertial navigation system (INS) feedback loops under extreme thermal cycling. IC Role / Device Role / Timing Role: Dual timing generator delivering matched, retriggerable enable signals to dual-axis gimbal drivers. Use Value: Maintains timing integrity from –55°C to +125°C with no drift compensation required; reset input ensures safe shutdown on fault detection.
Secure Communication Sync	Hardened Data Acquisition
Use Scenario: Synchronizing encryption key loading windows in TEMPEST-compliant crypto modules exposed to conducted EMI. IC Role / Device Role / Timing Role: Edge-triggered one-shot generating jitter-free strobes for secure memory access control. Use Value: Schmitt-trigger inputs reject >30% V_CC noise; CERDIP package prevents side-channel leakage through package parasitics.	Use Scenario: Conditioning analog-to-digital conversion triggers in radiation-hardened telemetry systems aboard satellites. IC Role / Device Role / Timing Role: Precision timing reference for sample-and-hold activation, immune to supply ripple and thermal transients. Use Value: Stable propagation delay (64 ns typ. at 5 V, –55°C to +125°C) ensures consistent sampling aperture timing across mission lifetime.

Radar Pulse Shaping

Missile Guidance Timing

Use Scenario: Generating precisely timed gate pulses to isolate RF return signals in pulsed Doppler radar receivers.

IC Role / Device Role / Timing Role: Monostable multivibrator providing adjustable blanking intervals synchronized to transmitter pulses.

Use Value: Enables rejection of near-field clutter via sub-microsecond pulse width control (t_W = 0.45·R_XC_X) with <±2% matching between dual channels.

Use Scenario: Controlling actuator enable windows in inertial navigation system (INS) feedback loops under extreme thermal cycling.

IC Role / Device Role / Timing Role: Dual timing generator delivering matched, retriggerable enable signals to dual-axis gimbal drivers.

Use Value: Maintains timing integrity from –55°C to +125°C with no drift compensation required; reset input ensures safe shutdown on fault detection.

Secure Communication Sync

Hardened Data Acquisition

Use Scenario: Synchronizing encryption key loading windows in TEMPEST-compliant crypto modules exposed to conducted EMI.

IC Role / Device Role / Timing Role: Edge-triggered one-shot generating jitter-free strobes for secure memory access control.

Use Value: Schmitt-trigger inputs reject >30% V_CC noise; CERDIP package prevents side-channel leakage through package parasitics.

Use Scenario: Conditioning analog-to-digital conversion triggers in radiation-hardened telemetry systems aboard satellites.

IC Role / Device Role / Timing Role: Precision timing reference for sample-and-hold activation, immune to supply ripple and thermal transients.

Use Value: Stable propagation delay (64 ns typ. at 5 V, –55°C to +125°C) ensures consistent sampling aperture timing across mission lifetime.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
CD54HCT123F3A	LSTTL-input compatible (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V); 4.5–5.5 V only; higher drive strength at 5 V	Required when interfacing directly with legacy TTL logic without level shifters; not suitable for 2–4 V systems	Select when system uses 5 V TTL signaling and demands guaranteed LSTTL compatibility over wide V_CC flexibility
CD74HC423E	Non-retriggerable architecture; identical pinout and timing but lacks pulse extension capability	Used where fixed-duration pulses are sufficient and retriggering introduces risk of timing ambiguity	Choose when deterministic, non-extendable pulse width is mandatory - e.g., watchdog timeout generation

Compared with CD54HCT123F3A and CD74HC423E, the CD54HC123F3A uniquely balances wide-voltage operation (2–6 V), retriggerability, and military temperature range - making it the only option for programmable pulse extension in multi-rail defense electronics.

Availability

CD54HC123F3A 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 and long product lifecycles.

Supply support for CD54HC123F3A 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 industrial, automotive, and defense markets.

The CD54HC123F3A belongs to TI's military-grade HC logic family, engineered for precision timing in mission-critical systems where environmental resilience, long-term stability, and QML certification are mandatory.

FAQ

What is the minimum external timing resistor value supported by the CD54HC123F3A?

The CD54HC123F3A specifies a minimum external timing resistor (R_X) of 5 kΩ. Using lower values may cause excessive current draw, timing inaccuracies, or output instability due to internal node loading effects. This value is confirmed across –55°C to +125°C in the Absolute Maximum Ratings and Timing Characteristics sections of the official TI datasheet SCHS142F.

Does the CD54HC123F3A support retriggering during an active output pulse?

Yes, the CD54HC123F3A is explicitly designed as a retriggerable monostable multivibrator. A new valid edge on either A or B input during an active output pulse will extend the pulse width by the full t_W interval, provided the retrigger time (t_rT) requirement is met - e.g., ≥76 ns at V_CC = 2 V, –55°C to +125°C per the Switching Specifications table.

How does the reset function behave on the CD54HC123F3A?

The reset input (R) on the CD54HC123F3A is active-low and asynchronous. When R is pulled LOW, it immediately forces Q = LOW and Q̅ = HIGH, terminating the current output pulse regardless of its remaining duration or trigger state. This override behavior is confirmed in the Truth Table and Functional Description sections of the CD54HC123F3A datasheet.

What is the typical output pulse width formula for the CD54HC123F3A?

The typical output pulse width for the CD54HC123F3A is calculated as t_W = 0.45 × R_X × C_X, where R_X is in ohms and C_X is in farads. This relationship holds at V_CC = 5 V and is specified in the Description section of the TI datasheet SCHS142F. Deviations increase at V_CC ≠ 5 V due to process-dependent "K factor" variation.

Is the CD54HC123F3A pin-compatible with the CD74HC123E?

No, the CD54HC123F3A is not pin-compatible with the CD74HC123E. While both are dual monostable multivibrators sharing functional equivalence, the CD54HC123F3A uses a 16-lead CERDIP package with specific pin assignments (e.g., dedicated 1RXCX/2RXCX pins), whereas the CD74HC123E uses a 16-lead PDIP package with different pin mapping - confirmed in the Pinout diagrams and Package Option Addendum of TI's documentation.

CD54HC123F3A Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 54HC

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:: 54 ns

Current - Output High, Low:: 5.2mA, 5.2mA

Voltage - Supply:: 2 V ~ 6 V

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 16-CDIP

CD54HC123F3A FAQ

1.How can I place an order for CD54HC123F3A through Aetrix?

Please submit a Request for Quotation (RFQ) for CD54HC123F3A 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 CD54HC123F3A reliable?

The price and inventory of CD54HC123F3A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD54HC123F3A is usually 5 days.

3.What payment methods are accepted for CD54HC123F3A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD54HC123F3A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for CD54HC123F3A?

CD54HC123F3A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your CD54HC123F3A 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 CD54HC123F3A?

For technical support, including CD54HC123F3A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD54HC123F3A requirements.

6.How does Aetrix verify that CD54HC123F3A is sourced from the original manufacturer or authorized distributors?

All CD54HC123F3A 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 CD54HC123F3A meets industry standards.

7.What is the process for return or replacement of CD54HC123F3A?

All CD54HC123F3A units undergo pre-shipment inspection (PSI). If there is an issue with CD54HC123F3A, 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 CD54HC123F3A part is unused and in its original packaging.

Return procedure for CD54HC123F3A:

1.Submit a request within 90 days.

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

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