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Texas Instruments CD14538BF3A
- Part No.:
- CD14538BF3A
- Manufacturer:
- Texas Instruments
- Category:
- Multivibrators
- Package:
- 16-CDIP (0.300", 7.62mm)
- Datasheet:
-
CD14538BF3A.pdf
- Description:
- CMOS DUAL PRECISION MONOSTABLE M
- Quantity:
- Payment:
- Shipping:
Inventory:1,659
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Product details
Overview
CD14538BF3A from Texas Instruments is a dual precision monostable multivibrator IC with independent trigger inputs, reset capability, and complementary Q/Q̅ outputs per section. It operates over -55°C to +125°C, supports 3V–18V supply, and features TTL/CMOS-compatible inputs. It serves in timing control, pulse shaping, and debouncing circuits in aerospace and industrial instrumentation.
For engineers reviewing the CD14538BF3A datasheet, CD14538BF3A pinout, CD14538BF3A application, or CD14538BF3A equivalent, key selection criteria include its dual-monostable architecture, wide temperature range, hermetic ceramic DIP-16 packaging, and compatibility with legacy CD4098B/CD4538B designs.
Technical Context
The CD14538BF3A implements two independent retriggerable monostable multivibrators, each with separate A/B trigger inputs, reset (R), and Q/Q̅ outputs. Timing is set externally via R-C networks connected to pins 13/14 (Section 1) and 2/3 (Section 2), enabling adjustable pulse widths from microseconds to seconds.
It uses standard CMOS silicon-gate technology with Schmitt-trigger inputs for noise immunity, supports asymmetric output drive (IOH = -0.36 mA, IOL = 4.2 mA at VDD = 5 V), and maintains stable operation across full military temperature range without derating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 3 V to 18 V - Enables direct interface with 3.3 V, 5 V, and 12 V logic systems without level shifters. |
| Operating Temperature | -55°C to +125°C - Qualified for military, avionics, and downhole industrial applications requiring extreme thermal resilience. |
| Propagation Delay | 100 ns typical at VDD = 10 V - Supports precise timing resolution in high-speed digital control loops. |
| Output Drive (IOL) | 4.2 mA at VDD = 5 V - Sufficient to directly drive LEDs, small relays, or CMOS/TTL fan-out of ≥10. |
| Input Hysteresis | ≈1.5 V at VDD = 5 V - Rejects >100 mV noise on trigger lines without external filtering. |
| Timing Accuracy | ±10% over temperature - Achieved via matched internal resistor ratios and low-drift capacitor coupling paths. |
Pinout & Package
CD14538BF3A is supplied in a 16-lead hermetic dual-in-line ceramic package (CDIP-J), with 0.3-inch body width, 0.6-inch length, and 0.25-inch lead pitch. The package meets MIL-STD-883 requirements for moisture resistance and long-term reliability in sealed environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15 | Trigger A (Section 1 & 2) | Active-low Schmitt-trigger input initiating monostable output pulse on corresponding section. |
| 2, 14 | Timing RC (Section 2 & 1) | Connect external resistor and capacitor to set pulse width; internal current source charges C. |
| 3, 13 | Timing RC (Section 2 & 1) | Second terminal of external RC network; defines timing constant τ ≈ 0.7 × R × C. |
| 4, 12 | Reset (Section 1 & 2) | Asynchronous active-low input forcing Q = 0 and Q̅ = 1 regardless of trigger state. |
| 5, 11 | Q Output (Section 1 & 2) | Non-inverted monostable output; goes high for duration set by RC network upon valid trigger. |
| 6, 10 | Q̅ Output (Section 1 & 2) | Inverted complement of Q; provides simultaneous active-low timing signal without external inverter. |
| 7 | GND | Ground reference for all internal circuitry and external RC components. |
| 16 | VDD | Positive supply rail; powers both sections and defines logic threshold levels. |
Key Features
| Feature | Design Value |
|---|---|
| Retriggerable operation | Allows new pulse initiation before prior one completes - essential for variable-rate event capture like encoder edge detection. |
| Independent dual sections | Enables two distinct timing functions (e.g., delay + pulse stretch) on single chip without crosstalk or shared RC constraints. |
| Complementary Q/Q̅ outputs | Eliminates need for external inverters in toggle or latch interfaces, reducing BOM count and layout area. |
| Military-grade hermetic seal | F3A suffix indicates ceramic DIP with glass-sealed leads - prevents moisture ingress and ensures >20-year shelf life in storage. |
Applications
| Encoder Debouncing | Pulse Width Modulation Control |
|---|---|
Use Scenario: Mechanical rotary encoder outputs noisy quadrature signals during contact bounce, causing false position counts in motion control systems. IC Role / Device Role / Timing Role: CD14538BF3A acts as dual-channel hardware debouncer - each section filters A/B phase signals with ~10 µs pulse suppression window. Use Value: Ensures clean, jitter-free quadrature edges delivered to microcontroller counters, eliminating missed or duplicate steps in servo positioning. | Use Scenario: Analog sensor output requires conversion to fixed-frequency PWM for isolated transmission across noisy industrial bus lines. IC Role / Device Role / Timing Role: CD14538BF3A generates precise PWM carrier (e.g., 10 kHz) using one section as oscillator and second as duty-cycle modulator via analog-controlled RC. Use Value: Delivers stable, temperature-compensated PWM with <±2% duty error - superior to RC-based 555 solutions under thermal cycling. |
| Power Sequencing Monitor | Aerospace Watchdog Timer |
Use Scenario: Multi-rail power supplies (e.g., ±15 V, +5 V, +3.3 V) must power up/down in strict sequence to avoid latch-up in mixed-signal FPGAs. IC Role / Device Role / Timing Role: CD14538BF3A provides cascaded delay stages - first section triggers second after fixed interval, enabling three-rail sequencing with two chips. Use Value: Replaces discrete RC timers with guaranteed monotonic delay behavior across -55°C to +125°C, eliminating cold-start failures. | Use Scenario: Avionics subsystems require fail-safe watchdog timeout that resets flight controller if software hangs longer than 250 ms. IC Role / Device Role / Timing Role: CD14538BF3A configured as non-retriggerable monostable - triggered by periodic MCU heartbeat; absence of refresh pulses causes Q̅ to assert reset. Use Value: Provides radiation-tolerant, single-point-of-failure-free watchdog function independent of processor clock domain or voltage regulators. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual monostable multivibrator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD4538B | Same pinout and function but obsolete; lacks military temp rating (-40°C to +85°C only); no hermetic packaging. | Not suitable for aerospace or extended-temperature industrial use; limited lifetime availability. | Select CD14538BF3A when full -55°C to +125°C operation and long-term supply stability are required. |
| MC14538 | Pin-compatible and functionally identical; manufactured by ON Semiconductor; RoHS-compliant plastic DIP option available. | Offers commercial/industrial temp grade only (-40°C to +85°C); no hermetic ceramic variant. | Choose MC14538 for cost-sensitive terrestrial applications where military specs are unnecessary. |
Compared with CD4538B and MC14538, the CD14538BF3A uniquely combines hermetic ceramic packaging, extended temperature qualification, and TI's long-term obsolescence management - making it the sole choice for mission-critical timing in defense and space platforms.
Availability
CD14538BF3A is available at Aetrix Electronics and suitable for aerospace instrumentation, downhole oilfield sensors, and military communications equipment requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for CD14538BF3A 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 CD14538BF3A belongs to TI's legacy CMOS logic family designed specifically for ruggedized timing applications where environmental resilience and long-term manufacturability outweigh raw speed or integration density.
FAQ
What is the maximum operating frequency of the CD14538BF3A?
The CD14538BF3A does not operate at a fixed clock frequency; instead, its output pulse width is determined by external RC networks. With minimum recommended R = 2 kΩ and C = 100 pF, the shortest stable pulse width is approximately 140 ns - corresponding to an effective timing resolution limit, not a clock rate. For repetitive triggering, practical upper repetition rates are ~1 MHz under ideal conditions, but depend on RC values and load capacitance.
Is the CD14538BF3A pin-compatible with the CD4098B?
Yes, the CD14538BF3A is explicitly stated in its datasheet as pin-compatible with the CD4098B. Both devices share identical pin assignments for triggers, resets, Q/Q̅ outputs, VDD, and GND. However, CD14538BF3A offers improved noise immunity via Schmitt-trigger inputs and wider supply voltage tolerance (3–18 V vs. 5–15 V for CD4098B), enabling direct drop-in replacement in most legacy designs.
Does the CD14538BF3A support retriggering during an active output pulse?
Yes, the CD14538BF3A is fully retriggerable: applying a new trigger pulse while Q is high restarts the timing cycle from zero, extending the total output pulse duration. This behavior is inherent to its internal architecture and requires no external circuitry - unlike non-retriggerable variants such as the 74HC123. Retriggering is validated across the full -55°C to +125°C range.
What is the significance of the 'F3A' suffix in CD14538BF3A?
The 'F3A' suffix identifies the CD14538BF3A as a 16-lead hermetic ceramic dual-in-line package (CDIP-J) qualified to military specifications. It denotes glass-sealed ceramic construction, 0.3-inch wide body, and compliance with MIL-STD-883 test methods. This distinguishes it from plastic DIP (E), SOIC (M), or TSSOP (PW) variants - all of which carry different suffixes and lack hermetic sealing.
Can the CD14538BF3A be used with a 3.3 V supply?
Yes, the CD14538BF3A is fully specified to operate at VDD = 3 V, with validated performance including propagation delay, output drive strength, and input hysteresis. At 3.3 V, typical IOL is 2.1 mA and IOH is -0.18 mA, sufficient to interface with 3.3 V CMOS loads. Input thresholds scale with VDD, maintaining reliable triggering without external level shifting.
CD14538BF3A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 4000B
- 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:
- 100 ns
- Current - Output High, Low:
- 6.8mA, 6.8mA
- Voltage - Supply:
- 3 V ~ 18 V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-CDIP
CD14538BF3A FAQ
1.How can I place an order for CD14538BF3A through Aetrix?
Please submit a Request for Quotation (RFQ) for CD14538BF3A 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 CD14538BF3A reliable?
The price and inventory of CD14538BF3A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD14538BF3A is usually 5 days.
3.What payment methods are accepted for CD14538BF3A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD14538BF3A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD14538BF3A?
CD14538BF3A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD14538BF3A 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 CD14538BF3A?
For technical support, including CD14538BF3A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD14538BF3A requirements.
6.How does Aetrix verify that CD14538BF3A is sourced from the original manufacturer or authorized distributors?
All CD14538BF3A 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 CD14538BF3A meets industry standards.
7.What is the process for return or replacement of CD14538BF3A?
All CD14538BF3A units undergo pre-shipment inspection (PSI). If there is an issue with CD14538BF3A, 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 CD14538BF3A part is unused and in its original packaging.
Return procedure for CD14538BF3A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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