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Texas Instruments CD74HCT139MT
- Part No.:
- CD74HCT139MT
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74HCT139MT.pdf
- Description:
- IC DECODER/DEMUX 1X2:4 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,820
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Product details
Overview
CD74HCT139MT from Texas Instruments is a dual 2-to-4 line decoder/demultiplexer IC with active-low enable and mutually exclusive active-low outputs. It operates from 4.5 V to 5.5 V, supports LSTTL-compatible inputs (VIL ≤ 0.8 V, VIH ≥ 2.0 V), delivers 10 LSTTL load fanout, and functions across –55 °C to +125 °C for industrial and aerospace systems requiring robust logic decoding.
For engineers reviewing the CD74HCT139MT datasheet, CD74HCT139MT pinout, CD74HCT139MT application, or CD74HCT139MT equivalent, this device is selected for memory address decoding, data routing in high-reliability embedded controllers, and demultiplexing control signals where TTL-level compatibility, wide temperature operation, and low quiescent current (<160 µA at 125 °C) are critical.
Technical Context
The CD74HCT139MT integrates two independent decoders, each with one active-low enable (1E/2E) and two binary select inputs (A0/A1), driving four active-low outputs (Y0–Y3). Enable acts as chip select during cascading and as data input in demultiplexer mode.
It uses HCT logic architecture-CMOS process with TTL-compatible input thresholds-ensuring direct replacement of LS-series devices without level-shifting. Propagation delays are 34 ns (max, –55 °C to +125 °C) for both select-to-output and enable-to-output paths under 50 pF load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures stable operation in standard 5 V TTL/CMOS mixed-signal systems without regulation overhead. |
| Input Logic Compatibility | VIL ≤ 0.8 V (max), VIH ≥ 2.0 V (min) - Directly interfaces with legacy 74LS TTL outputs without pull-ups or translators. |
| Output Drive | 10 LSTTL loads - Sufficient to drive multiple downstream TTL gates or small bus segments without buffering. |
| Propagation Delay | 51 ns (max, –55 °C to +125 °C, CL = 50 pF) - Enables reliable timing in sub-20 MHz address/data path applications. |
| Operating Temperature | –55 °C to +125 °C - Qualified for extended-range industrial, avionics, and downhole electronics environments. |
| Quiescent Current | 160 µA (max, –55 °C to +125 °C) - Supports low-power standby modes in battery-backed or energy-constrained systems. |
| Input Leakage | ±1 µA (max, –55 °C to +125 °C) - Minimizes unintended switching in high-impedance or long-trace configurations. |
Pinout & Package
CD74HCT139MT is housed in a 16-pin SOIC (D) package with 1.27 mm pitch, JEDEC MS-012 compliant, moisture sensitivity level 1 (260 °C reflow), and RoHS-compliant NiPdAu lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1E, 2E | Active-low enable input | Disables all outputs (drives Y0–Y3 high) when high; enables decoding/demux when low. |
| 1A0, 1A1 / 2A0, 2A1 | Binary select inputs | Two-bit address selects exactly one active-low output per decoder (Y0–Y3). |
| 1Y0–1Y3 / 2Y0–2Y3 | Active-low decoded outputs | Only one output per decoder goes low per valid A0/A1 combination; outputs are mutually exclusive. |
| VCC (Pin 16) | Positive supply | Connects to 4.5–5.5 V rail; decoupling capacitor required near pin for noise immunity. |
| GND (Pin 8) | Ground reference | Common return for all inputs, outputs, and internal logic; must be low-impedance. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent decoders | Enables simultaneous decoding of two separate 2-bit address buses-e.g., memory bank + peripheral select-in single-package space savings. |
| Active-low enable with chip-select capability | Allows hierarchical addressing: one CD74HCT139MT can enable another, supporting up to 16-device decoding trees without external logic. |
| LSTTL-compatible input thresholds | Eliminates need for level shifters when interfacing with legacy 74LS, 74ALS, or microcontroller GPIOs operating at 5 V. |
| Wide temperature range support | Validated operation from –55 °C to +125 °C ensures reliability in uncontrolled enclosures, engine compartments, or space-grade PCBs. |
| Low dynamic power consumption | CPD = 59 pF enables <1 mW typical dynamic power at 1 MHz, reducing thermal load in dense logic arrays. |
Applications
| Memory Address Decoding | Data Routing in Industrial PLCs |
|---|---|
|
Use Scenario: Selecting one of four RAM or ROM chips in a microcontroller-based data acquisition system. IC Role / Device Role / Timing Role: Decoder translates upper address bits into chip-select signals, synchronizing with CPU read/write strobes. Use Value: Eliminates discrete gate logic; ensures glitch-free selection via mutually exclusive outputs and balanced propagation delay. |
Use Scenario: Distributing command signals from a central controller to four independent I/O modules in a programmable logic controller. IC Role / Device Role / Timing Role: Demultiplexer routes serial control bits to parallel module-enable lines with deterministic setup/hold timing. Use Value: Reduces wiring complexity and PCB layer count while maintaining signal integrity across 10+ cm backplane traces. |
| Code Conversion in Sensor Interfaces | Cascaded Chip Selection in Avionics Systems |
|
Use Scenario: Converting 2-bit configuration codes from an analog sensor into four discrete calibration-path enables. IC Role / Device Role / Timing Role: Binary decoder activates one of four precision resistor networks or op-amp gain stages. Use Value: Provides monotonic, bounce-free switching between calibrated ranges-critical for ±0.1% measurement accuracy. |
Use Scenario: Enabling one of four redundant flight-control processors using a master arbitration bus. IC Role / Device Role / Timing Role: First-stage decoder selects secondary decoder ICs; enable chaining ensures fail-safe priority sequencing. Use Value: Meets DO-254 Level A timing constraints with verified worst-case 51 ns propagation and no metastability risk. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual 2-to-4 decoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT139DR | Same HCT logic family, identical pinout, but rated only for –40 °C to +85 °C industrial range. | Not suitable for extended-temperature deployments (e.g., automotive under-hood, military field units). | Select CD74HCT139MT when full –55 °C to +125 °C qualification is required; SN74HCT139DR suffices for commercial-grade boards. |
| CD4556BM96 | CMOS (4000B series), 3–18 V operation, higher propagation delay (120 ns min at 5 V), no TTL input compatibility. | Requires level-shifting for TTL sources; used where ultra-low static power (<100 nA) outweighs speed needs. | Choose CD4556BM96 only in battery-powered, low-frequency systems; CD74HCT139MT preferred for TTL interoperability and speed. |
Compared with SN74HCT139DR and CD4556BM96, CD74HCT139MT uniquely combines military-grade temperature range, guaranteed LSTTL input compatibility, and sub-55 ns propagation-making it the sole option for high-reliability 5 V systems demanding drop-in replaceability of legacy 74LS139 without redesign.
Availability
CD74HCT139MT is available at Aetrix Electronics and suitable for memory decoding, industrial PLC I/O expansion, sensor calibration path selection, and avionics subsystem enablement requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74HCT139MT 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 logic solutions, with over 50 years of high-reliability component development.
The CD74HCT139MT belongs to TI's High-Speed CMOS Logic (HCT) family-designed specifically for seamless 5 V TTL-to-CMOS migration in industrial, aerospace, and defense systems where interoperability and ruggedness are non-negotiable.
FAQ
What is the maximum operating voltage for CD74HCT139MT?
The CD74HCT139MT has an absolute maximum supply voltage of 7 V, but its specified functional operating range is strictly 4.5 V to 5.5 V. Operating outside this window risks violating input threshold guarantees and may cause undefined output states or accelerated parametric drift. Always regulate to 5.0 V ±5% for compliance with LSTTL compatibility and timing specifications in the CD74HCT139MT datasheet.
Is CD74HCT139MT pin-compatible with CD4556B?
Yes, CD74HCT139MT is explicitly stated in the official datasheet as functionally identical and pin-compatible with CD4556B. Both share identical pin assignments for enables, select inputs, outputs, VCC, and GND in the 16-pin SOIC package. However, CD74HCT139MT offers faster propagation (51 ns vs. 120 ns), TTL-compatible inputs, and tighter temperature grading-making it a performance upgrade without layout changes.
Can CD74HCT139MT drive LED indicators directly?
No, CD74HCT139MT outputs are not designed for direct LED drive. Its absolute maximum output sink current is ±25 mA per pin, but recommended steady-state drive is limited to 4 mA (TTL load level) to maintain VOH ≥ 3.7 V and VOL ≤ 0.4 V. For LED indication, use a series current-limiting resistor ≥1 kΩ with VCC = 5 V, or add a discrete transistor buffer for higher-current LEDs.
Does CD74HCT139MT require external pull-up resistors on its outputs?
No, CD74HCT139MT features totem-pole CMOS outputs capable of actively driving both high and low logic states. Its outputs are fully buffered and do not rely on external pull-ups. Adding pull-ups would create contention during low-output periods and increase power dissipation-contrary to the CD74HCT139MT's design intent of low-power, rail-to-rail switching.
What is the meaning of the "T" suffix in CD74HCT139MT?
The "T" suffix in CD74HCT139MT indicates a small-quantity tape-and-reel packaging option containing 250 units per reel, optimized for prototyping, NPI builds, and low-volume production. This contrasts with the "M96" variant (2500 units/reel) for high-volume manufacturing. Both share identical electrical specs, SOIC package dimensions, and temperature rating-only packaging quantity and reel size differ.
CD74HCT139MT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 2:4
- Independent Circuits:
- 2
- Current - Output High, Low:
- 4mA, 4mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
CD74HCT139MT FAQ
1.How can I place an order for CD74HCT139MT through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT139MT 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 CD74HCT139MT reliable?
The price and inventory of CD74HCT139MT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT139MT is usually 5 days.
3.What payment methods are accepted for CD74HCT139MT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT139MT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HCT139MT?
CD74HCT139MT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT139MT 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 CD74HCT139MT?
For technical support, including CD74HCT139MT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT139MT requirements.
6.How does Aetrix verify that CD74HCT139MT is sourced from the original manufacturer or authorized distributors?
All CD74HCT139MT 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 CD74HCT139MT meets industry standards.
7.What is the process for return or replacement of CD74HCT139MT?
All CD74HCT139MT units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT139MT, 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 CD74HCT139MT part is unused and in its original packaging.
Return procedure for CD74HCT139MT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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