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Texas Instruments SN74HCT139DR
- Part No.:
- SN74HCT139DR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74HCT139DR.pdf
- Description:
- IC DECODER/DEMUX 1X2:4 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:10,371
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Product details
Overview
SN74HCT139DR from Texas Instruments is a dual 2-line-to-4-line decoder/demultiplexer in SOIC-16 package, operating at 4.5–5.5 V, with 10 ns typical propagation delay, ±4-mA output drive, and TTL-compatible inputs. It serves as a high-speed memory address decoder or data routing switch in industrial control and embedded systems.
For engineers reviewing the SN74HCT139DR datasheet, SN74HCT139DR pinout, SN74HCT139DR application, or SN74HCT139DR equivalent, key selection criteria include enable-input cascading capability, LSTTL load drive (10 loads), low ICC (80 µA max), input leakage (<1 µA), and guaranteed operation across –40°C to +85°C.
Technical Context
The SN74HCT139DR integrates two independent decoders, each with active-low enable (G) and dual address inputs (A, B), producing four active-low decoded outputs (Y0–Y3). Its fully buffered inputs present only one normalized load, minimizing fanout burden on upstream logic.
Propagation delay is tightly specified (12–51 ns over voltage/temperature), and switching behavior is characterized with CL = 50 pF. The device uses HCT logic family architecture-CMOS process with TTL-level input thresholds-ensuring compatibility with legacy 74LS systems while delivering lower power and higher noise immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures stable operation with standard 5-V rail; no regulation required for nominal use. |
| Propagation Delay (tpd) | 12 ns (min) to 40 ns (max) at 5.5 V - Enables sub-25-MHz synchronous decoding without timing closure issues. |
| Output Drive | ±4 mA at 5 V - Directly interfaces with 10 LSTTL loads; eliminates need for buffer stages in medium-density logic. |
| Input Leakage Current | ≤1 µA max - Prevents unintended logic transitions when inputs are pulled via high-value resistors (e.g., 100 kΩ). |
| Operating Temperature | –40°C to +85°C - Qualified for industrial environments including motor drives, PLC I/O modules, and instrumentation. |
| Power Supply Current (ICC) | 80 µA max - Supports low-static-power system design; contributes <0.4 mW per decoder at 5 V. |
| Input Compatibility | TTL-voltage compatible (VIH = 2 V, VIL = 0.8 V) - Interoperates seamlessly with 74LS, 74F, and microcontroller GPIO without level shifters. |
Pinout & Package
SN74HCT139DR is housed in a 16-pin SOIC (D) package, 9.90 mm × 3.90 mm body size, with 1.27-mm lead pitch and RoHS-compliant NiPdAu/Sn lead finish. Moisture sensitivity level is Level-1 (unlimited floor life at ≤30°C/60% RH).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 13, 14, 15, 16 | Decoder Inputs & Outputs (G1, A1, B1, Y0–Y3, G2, A2, B2, Y0–Y3) | Two independent decoder sections: Section 1 (pins 1–7, 15–16), Section 2 (pins 13–14, 8–12); all outputs are active-low. |
| 7 | GND | Ground reference for both decoders and internal logic; must be low-impedance connection. |
| 16 | VCC | Positive supply for CMOS logic core; requires local 0.1-µF bypass capacitor per TI recommendation. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent decoders | Enables compact implementation of two separate 2:4 decode paths-e.g., memory bank select + peripheral enable-in single IC. |
| Active-low enable (G) per section | Allows hierarchical cascading: output of one decoder can gate enable of another, supporting 3:8 or 4:16 expansion without external gates. |
| Full input buffering | Each input presents only one normalized load, reducing loading on driving sources and preserving signal integrity in fanout-critical paths. |
| High noise immunity | Input thresholds (VIH = 2 V, VIL = 0.8 V) provide >1.2 V noise margin at 5 V, critical for noisy industrial PCB layouts. |
| Low dynamic power | 25 pF typical power dissipation capacitance per decoder limits switching current and EMI in high-frequency address bus applications. |
Applications
| Industrial Memory Decoding | Microcontroller Peripheral Selection |
|---|---|
|
Use Scenario: Selecting among eight SRAM or EEPROM chips in a PLC backplane using a 3-bit address bus. IC Role / Device Role / Timing Role: Dual decoder implements 3:8 decoding by cascading G2 to Y0 of first section; provides deterministic 40-ns worst-case address-to-output delay. Use Value: Eliminates discrete gate count and reduces PCB area versus two 74LS138s; maintains full timing margin at 20-MHz bus clock. |
Use Scenario: Routing UART, SPI, and I²C peripherals from an ARM Cortex-M0+ MCU with limited GPIO. IC Role / Device Role / Timing Role: Acts as addressable peripheral enable controller: A/B select interface, G enables/disables entire block; supports hot-plug detection via G monitoring. Use Value: Reduces firmware complexity by offloading chip-select arbitration; TTL-compatible inputs accept direct MCU GPIO without level translation. |
| Legacy System Logic Replacement | Test Equipment Signal Routing |
|
Use Scenario: Upgrading aging 74LS139-based test fixture control logic to reduce power and improve reliability. IC Role / Device Role / Timing Role: Pin-for-pin drop-in replacement for SN74LS139; identical pinout and function table, but with CMOS power efficiency and wider VCC tolerance. Use Value: Cuts board-level quiescent power by >90% (vs. LS), extends thermal margin, and eliminates LS-family obsolescence risk. |
Use Scenario: Multiplexing calibration signals between DMM, oscilloscope, and signal generator in automated test equipment. IC Role / Device Role / Timing Role: Functions as demultiplexer: G driven by controller selects path; A/B route one of four precision references to DUT. Use Value: Guarantees monotonic switching (no glitches during address change) due to fully buffered inputs and synchronous enable architecture. |
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 |
|---|---|---|---|
| SN74HC139DR | Higher VCC range (2–6 V), slower tpd (29–60 ns), lower drive (±4 mA still valid), no TTL input compatibility. | Suitable for battery-powered or mixed-voltage systems; not interoperable with legacy 5-V TTL logic without level shifting. | Select when wide supply flexibility matters more than TTL compatibility or speed. |
| 74ACT139SCX | Faster tpd (6–12 ns), higher drive (±24 mA), 5-V-only operation, same pinout and function table. | Better for high-speed bus arbitration or driving heavier capacitive loads (>50 pF); higher ICC (4 µA typ) increases static power. | Select when propagation delay <12 ns is mandatory and power budget allows ~50× higher ICC than SN74HCT139DR. |
Compared with SN74HC139DR and 74ACT139SCX, the SN74HCT139DR uniquely balances TTL compatibility, industrial temperature range, and ultra-low ICC-making it optimal for cost-sensitive, noise-prone, or legacy-interfacing designs where 10-ns delay suffices.
Availability
SN74HCT139DR is available at Aetrix Electronics and suitable for industrial control systems, embedded instrumentation, and legacy logic upgrades requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for SN74HCT139DR 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 decades of expertise in industrial-grade logic families.
The SN74HCT139DR belongs to TI's HCT logic series-designed specifically for seamless migration from bipolar TTL systems while delivering CMOS efficiency, reliability, and noise immunity in industrial and automotive-adjacent applications.
FAQ
What is the maximum clock frequency supported by SN74HCT139DR in demultiplexer mode?
The SN74HCT139DR does not operate on a clock signal-it is combinational logic. Its usable data rate depends on propagation delay and load capacitance. With CL = 50 pF and VCC = 5.5 V, worst-case tpd is 40 ns, supporting reliable address/data routing up to ~12 MHz toggle rate in synchronous systems. For SN74HCT139DR, timing margins must be verified against system setup/hold requirements-not clock frequency.
Can SN74HCT139DR drive LEDs directly?
No. SN74HCT139DR outputs are active-low and rated for ±4 mA at 5 V, which is insufficient to drive standard indicator LEDs (typically requiring 10–20 mA). Using it directly risks exceeding output current limits and degrading VOL. For LED interfacing, add a discrete NPN transistor or dedicated LED driver stage. The SN74HCT139DR is intended for logic-level signal routing-not power switching.
Is SN74HCT139DR pin-compatible with SN74LS139N?
Yes. SN74HCT139DR (SOIC-16) and SN74LS139N (PDIP-16) share identical pin functions and ordering logic, including active-low enables and outputs. Though package differs, the signal mapping is identical-enabling direct PCB redesign from through-hole to surface-mount without netlist changes. Function table, timing, and DC specs differ, but pinout alignment is maintained per TI documentation.
Does SN74HCT139DR require external pull-up resistors on its outputs?
No. SN74HCT139DR features totem-pole (push-pull) outputs capable of actively driving high or low. Pull-ups are unnecessary and would cause contention during low-state output, increasing power and risking damage. Outputs should connect directly to LSTTL inputs or other CMOS logic. Unused inputs-not outputs-must be tied to VCC or GND per TI guidelines.
What is the thermal resistance (RθJA) of SN74HCT139DR in its SOIC package?
The SN74HCT139DR in SOIC (D) package has a junction-to-ambient thermal resistance (RθJA) of 73°C/W, as specified in TI's SCLS066E datasheet. This value assumes standard JEDEC 2-layer board conditions. Under typical industrial ambient (85°C) and 80-µA ICC, self-heating remains negligible (<0.006°C), confirming suitability for convection-cooled applications without heatsinking.
SN74HCT139DR 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:
- Active
- 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:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74HCT139DR FAQ
1.How can I place an order for SN74HCT139DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT139DR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
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The price and inventory of SN74HCT139DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT139DR is usually 5 days.
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Once your SN74HCT139DR 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 SN74HCT139DR?
For technical support, including SN74HCT139DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT139DR requirements.
6.How does Aetrix verify that SN74HCT139DR is sourced from the original manufacturer or authorized distributors?
All SN74HCT139DR 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 SN74HCT139DR meets industry standards.
7.What is the process for return or replacement of SN74HCT139DR?
All SN74HCT139DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT139DR, 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 SN74HCT139DR part is unused and in its original packaging.
Return procedure for SN74HCT139DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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