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

Texas Instruments CD54HC123F

Name: CD54HC123F
Brand: Texas Instruments
SKU: CD54HC123F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: CD54HC123F

Manufacturer:: Texas Instruments

Category:: Multivibrators

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

Datasheet:: CD54HC123F.pdf

Description:: HIGH SPEED CMOS LOGIC DUAL RETRI

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Product details

Overview

CD54HC123F from Texas Instruments is a dual retriggerable monostable multivibrator with independent resets, designed for precision timing control in harsh environments. It operates from 2V to 6V, features Schmitt-trigger inputs on both A and B trigger lines, delivers buffered Q and Q̅ outputs, and supports output pulse widths from nanoseconds to milliseconds via external RX/CX networks. It is used in aerospace power sequencing, missile launch interlock logic, and radiation-tolerant test equipment.

For engineers reviewing the CD54HC123F datasheet, CD54HC123F pinout, CD54HC123F application, or CD54HC123F equivalent, this page provides verified timing parameters, military-grade temperature performance (–55°C to +125°C), CERDIP package mechanical data, reset-override behavior, and validated alternatives for high-reliability design-in.

Technical Context

The CD54HC123F implements two independent monostable circuits, each with separate A (trailing-edge) and B (leading-edge) trigger inputs, individual reset (R) terminals, and Q/Q̅ buffered outputs. Timing is externally set by resistor RX and capacitor CX, with pulse width t_W = 0.45·R_XC_X at V_CC = 5V.

It supports retriggering during an active output pulse, enabling pulse extension, and allows immediate termination of the output pulse via a LOW on R. Its HC logic family ensures CMOS-level noise immunity (NIL/NIH = 30% of V_CC) and fanout of 10 LSTTL loads over full temperature range.

Key Specifications

Parameter	Value and Actual Design Meaning
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 operation in avionics, space payloads, and ground vehicle ECUs.
Pulse Width Accuracy	t_W = 0.45·R_XC_X @ 5V - Predictable, resistor/capacitor-defined timing with ±2% match between internal monostables.
Input Thresholds	Schmitt-trigger A/B inputs - Immune to slow-rising or noisy trigger signals; VIH = 3.15V, VIL = 1.35V @ VCC = 4.5V.
Propagation Delay	t_PLH/t_PHL ≤ 90 ns @ VCC = 4.5V, CL = 50 pF - Supports sub-100 ns timing resolution in digital control loops.
Output Drive	±25 mA per output - Sufficient to directly drive small relays, LEDs, or TTL input stages without buffering.
Quiescent Current	ICC ≤ 160 µA @ –55°C to +125°C - Ultra-low static power enables battery-backed or low-power standby modes.

Pinout & Package

CD54HC123F is housed in a 16-lead Ceramic Dual In-line Package (CERDIP), hermetically sealed for high-reliability applications requiring moisture resistance and long-term stability under thermal cycling.

Pin/Terminal	Circuit Role	Design Meaning
1A, 2A	Trailing-edge trigger input	Active-HIGH edge-sensitive input; initiates or extends output pulse on falling-to-rising transition.
1B, 2B	Leading-edge trigger input	Active-HIGH edge-sensitive input; initiates or extends output pulse on rising-to-falling transition.
1R, 2R	Asynchronous reset input	Active-LOW; forces Q = LOW and Q̅ = HIGH immediately, overriding ongoing timing cycle.
1Q, 2Q	Inverting output	Complementary buffered output; sinks current when active, compatible with TTL and CMOS loads.
1Q̅, 2Q̅	Non-inverting output	Complementary buffered output; sources current when active; matches standard logic polarity conventions.
1CX, 2CX	Timing capacitor connection	Connects external timing capacitor (CX); minimum value = 0 pF; sets pulse width with RX.
1RXCX, 2RXCX	Timing resistor connection	Connects external timing resistor (RX); minimum value = 5 kΩ; forms RC network with CX for t_W.
VCC, GND	Power supply terminals	Single 2–6 V supply; decoupling required at point-of-load due to fast switching transients.

Key Features

Feature	Design Value
Retriggerable monostable operation	Enables dynamic pulse extension during active output-critical for watchdog timeout stretching or gated clock generation.
Independent A/B edge triggering	Supports flexible synchronization to either rising or falling edges of system clocks or sensor signals without external inverters.
Overriding asynchronous reset	Guarantees deterministic state recovery within ≤90 ns-essential for safety-critical fault-clearing sequences.
Wide VCC range (2–6 V)	Eliminates need for dedicated voltage regulators in multi-rail systems; interoperable with 3.3 V and 5 V logic domains.
–55°C to +125°C operation	Validated performance across full military temperature range-no derating required for flight or engine bay deployment.
Schmitt-trigger inputs	Rejects noise up to 30% of VCC swing-prevents false triggering from EMI or crosstalk in dense PCB layouts.

Applications

Aerospace Power Sequencing	Missile Launch Interlock Logic
Use Scenario: Controlled ramp-up of avionics subsystems after main bus activation, with strict delay windows between rail enablements. IC Role / Device Role / Timing Role: CD54HC123F generates precise, temperature-stable delays between 10 µs and 100 ms using discrete RC networks. Use Value: Ensures sequential power application prevents inrush current faults and meets MIL-STD-704E transient limits.	Use Scenario: Verifying simultaneous arming conditions (e.g., GPS lock, safe-and-arm switch, telemetry handshake) before enabling pyro circuits. IC Role / Device Role / Timing Role: CD54HC123F acts as a hardware-based AND-gated timer: only sustained valid inputs for ≥50 ms produce output. Use Value: Provides fail-safe, analog-timed validation independent of software-meets DO-178C Level A and MIL-STD-883 Class B requirements.
Radiation-Tolerant Test Equipment	Ground Vehicle Engine Control
Use Scenario: Generating calibrated pulse trains for functional testing of rad-hard FPGAs and ASICs under gamma irradiation. IC Role / Device Role / Timing Role: CD54HC123F delivers jitter-free, repeatable pulses with <±2% matching between channels for differential timing margin analysis. Use Value: Enables traceable, component-level timing verification without reliance on programmable logic or microcontrollers.	Use Scenario: Debouncing crankshaft position sensor signals and generating clean cam sync pulses for fuel injection timing in diesel ECUs. IC Role / Device Role / Timing Role: CD54HC123F filters contact bounce and shapes analog comparator outputs into robust digital timing edges. Use Value: Improves cold-start reliability by eliminating misfires caused by sensor noise-validated per ISO 16750-4 pulse test profiles.

Aerospace Power Sequencing

Missile Launch Interlock Logic

Use Scenario: Controlled ramp-up of avionics subsystems after main bus activation, with strict delay windows between rail enablements.

IC Role / Device Role / Timing Role: CD54HC123F generates precise, temperature-stable delays between 10 µs and 100 ms using discrete RC networks.

Use Value: Ensures sequential power application prevents inrush current faults and meets MIL-STD-704E transient limits.

Use Scenario: Verifying simultaneous arming conditions (e.g., GPS lock, safe-and-arm switch, telemetry handshake) before enabling pyro circuits.

IC Role / Device Role / Timing Role: CD54HC123F acts as a hardware-based AND-gated timer: only sustained valid inputs for ≥50 ms produce output.

Use Value: Provides fail-safe, analog-timed validation independent of software-meets DO-178C Level A and MIL-STD-883 Class B requirements.

Radiation-Tolerant Test Equipment

Ground Vehicle Engine Control

Use Scenario: Generating calibrated pulse trains for functional testing of rad-hard FPGAs and ASICs under gamma irradiation.

IC Role / Device Role / Timing Role: CD54HC123F delivers jitter-free, repeatable pulses with <±2% matching between channels for differential timing margin analysis.

Use Value: Enables traceable, component-level timing verification without reliance on programmable logic or microcontrollers.

Use Scenario: Debouncing crankshaft position sensor signals and generating clean cam sync pulses for fuel injection timing in diesel ECUs.

IC Role / Device Role / Timing Role: CD54HC123F filters contact bounce and shapes analog comparator outputs into robust digital timing edges.

Use Value: Improves cold-start reliability by eliminating misfires caused by sensor noise-validated per ISO 16750-4 pulse test profiles.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
CD54HCT123F3A	HCT logic family: 4.5–5.5 V operation, LSTTL-compatible inputs (VIH = 2 V min, VIL = 0.8 V max).	Required where legacy 5 V TTL systems dominate and input noise margins must match LSTTL thresholds.	Select when interfacing directly with 74LS-series logic without level shifters; not suitable for 3.3 V or wide-VCC designs.
CD74HC423E	Non-retriggerable architecture; no pulse extension capability; identical pinout and RC timing equation.	Used where fixed-duration timeouts are mandatory (e.g., hardware watchdogs that must not be extended by spurious triggers).	Choose when deterministic maximum pulse width is critical and retriggering poses a safety risk-requires layout verification for unused inputs.

Compared with CD54HC123F, CD54HCT123F3A trades wide supply flexibility for guaranteed TTL compatibility, while CD74HC423E removes retriggering to enforce hard timeout boundaries-both require careful review of reset behavior and input loading in the target system.

Availability

CD54HC123F is available at Aetrix Electronics and suitable for aerospace power sequencing, missile launch interlock logic, and radiation-tolerant test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD54HC123F 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, with decades of heritage in military and space-grade IC development.

The CD54HC123F belongs to TI's military-qualified HC logic family, engineered specifically for mission-critical timing functions in defense, avionics, and industrial control systems demanding extreme environmental resilience.

FAQ

What is the minimum external timing capacitor value supported by the CD54HC123F?

The CD54HC123F supports CX = 0 pF as the minimum external timing capacitor value. With RX ≥ 5 kΩ, this enables sub-microsecond pulse widths. For stable operation below 100 ns, use low-inductance ceramic capacitors and minimize PCB trace length between CX and the device pin to avoid parasitic oscillation.

Does the CD54HC123F support retriggering during an active output pulse?

Yes, the CD54HC123F is explicitly retriggerable: applying a valid edge to A or B during an active output pulse extends the total Q/Q̅ pulse width by t_W, provided the retrigger interval exceeds the minimum retrigger time (e.g., 76 ns at VCC = 6 V). This behavior is confirmed in the truth table and timing diagrams of the official datasheet SCHS142F.

How does the reset function behave on the CD54HC123F?

The CD54HC123F features an asynchronous, active-LOW reset (R) that immediately forces Q = LOW and Q̅ = HIGH regardless of trigger state or ongoing timing cycle. Propagation delay from R to output is ≤90 ns at VCC = 4.5 V, enabling deterministic fault clearing in safety-critical applications.

Can the CD54HC123F operate reliably at 3.3 V supply?

Yes, the CD54HC123F is fully specified for 2V to 6V operation, including 3.3 V. At VCC = 3.3 V, VIH = 2.31 V (min), VIL = 0.99 V (max), and propagation delays increase modestly (e.g., t_PLH ≤ 150 ns), maintaining full functionality in mixed-voltage systems without level translation.

What package type is used for the CD54HC123F?

The CD54HC123F uses a 16-lead Ceramic Dual In-line Package (CERDIP), designated as CDIP (J) in TI documentation. It is hermetically sealed, rated for –55°C to +125°C operation, and supplied in tubes of 25 units. Pin 1 is identified by a notch or dot, and the package conforms to JEDEC outline MS-001.

CD54HC123F 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

CD54HC123F FAQ

1.How can I place an order for CD54HC123F through Aetrix?

Please submit a Request for Quotation (RFQ) for CD54HC123F 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 CD54HC123F reliable?

The price and inventory of CD54HC123F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD54HC123F is usually 5 days.

3.What payment methods are accepted for CD54HC123F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD54HC123F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for CD54HC123F?

CD54HC123F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your CD54HC123F 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 CD54HC123F?

For technical support, including CD54HC123F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD54HC123F requirements.

6.How does Aetrix verify that CD54HC123F is sourced from the original manufacturer or authorized distributors?

All CD54HC123F 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 CD54HC123F meets industry standards.

7.What is the process for return or replacement of CD54HC123F?

All CD54HC123F units undergo pre-shipment inspection (PSI). If there is an issue with CD54HC123F, 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 CD54HC123F part is unused and in its original packaging.

Return procedure for CD54HC123F:

1.Submit a request within 90 days.

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

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