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Texas Instruments SN74HCT139PWT
- Part No.:
- SN74HCT139PWT
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74HCT139PWT.pdf
- Description:
- IC DECODER/DEMUX 1X2:4 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:718
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Product details
Overview
SN74HCT139PWT from Texas Instruments is a dual 2-line-to-4-line decoder/demultiplexer in a 16-pin TSSOP 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 compact embedded control systems.
For engineers reviewing the SN74HCT139PWT datasheet, SN74HCT139PWT pinout, SN74HCT139PWT application, or SN74HCT139PWT equivalent, key selection criteria include its dual-decoder architecture with active-low enable, low 80-µA max ICC supply current, and compatibility with LSTTL loads in space-constrained PCB layouts.
Technical Context
The SN74HCT139PWT integrates two independent 2-to-4 line decoders sharing no internal logic-each with dedicated A/B select inputs and active-low G enable. Its fully buffered inputs present only one normalized load, minimizing fanout burden on upstream drivers.
Propagation delay is specified at 10 ns (typ) under 5-V operation with 50-pF load, and switching behavior follows strict positive-logic truth table where outputs Y0–Y3 go low only when G = L and corresponding A/B combination matches. No internal pull-ups or level-shifting circuitry is present.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL and mixed-voltage logic systems without level shifters. |
| Propagation Delay (tpd) | 10 ns typical at 5 V, CL = 50 pF - enables use in sub-100-MHz address decoding paths without adding critical timing slack. |
| Output Drive | ±4 mA at 5 V - directly interfaces up to 10 LSTTL loads per output, eliminating need for buffer stages in moderate-fanout designs. |
| Input Compatibility | TTL-voltage compatible (VIH = 2 V min, VIL = 0.8 V max) - accepts standard TTL logic levels without external biasing or translation. |
| Supply Current (ICC) | 80 µA max - supports low-static-power operation in battery-backed or always-on control subsystems. |
| Input Leakage | ±1 µA max - prevents unintended logic transitions when inputs are tied to VCC/GND via high-value resistors. |
Pinout & Package
SN74HCT139PWT uses a 16-pin Thin Shrink Small Outline Package (TSSOP-PW) with 0.65-mm lead pitch, 5.00 mm × 4.40 mm body size, and 1.2-mm max height. Pin 1 is marked by a corner chamfer and located in Quadrant Q1 per JEDEC MO-153.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15, 16 | G1, G2, VCC | Active-low enable inputs (G1/G2) independently control each decoder; VCC powers both sections-no separate supplies required. |
| 2, 3, 4, 5 | A1, B1, Y10, Y11 | First decoder: A1/B1 select lines; Y10–Y13 (pins 4, 5, 6, 7) are active-low decoded outputs. |
| 6, 7, 10, 11 | Y12, Y13, A2, B2 | Y12/Y13 complete first decoder outputs; A2/B2 are second decoder select inputs. |
| 12, 13, 14, 9 | Y20, Y21, Y22, Y23 | Second decoder outputs (active-low), mapped to pins 12, 13, 14, 9 - sequential but non-contiguous due to pinout optimization. |
| 8 | GND | Single ground reference for entire device - requires local 0.1-µF bypass capacitor per TI layout guidance. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent decoders | Enables two parallel 2-to-4 decode paths (e.g., memory bank + peripheral select) without inter-stage coupling or shared timing constraints. |
| Active-low enable (G) | Allows cascading multiple SN74HCT139PWT devices using one decoder's output to drive another's G input-simplifies hierarchical address decoding. |
| Full input buffering | Each input presents only one normalized load, reducing loading on preceding gates and preserving signal integrity in multi-stage logic trees. |
| Low ICC quiescent current | 80 µA max ensures minimal contribution to system standby power-critical for industrial controllers with extended sleep modes. |
| TTL-compatible thresholds | VIH ≥ 2 V and VIL ≤ 0.8 V allow direct connection to legacy 5-V TTL outputs without interface components or voltage translation. |
Applications
| Memory Address Decoding | Peripheral Select Logic |
|---|---|
|
Use Scenario: Selecting one of four SRAM chips in a microcontroller-based data logger using A0–A1 address bits. IC Role / Device Role / Timing Role: SN74HCT139PWT acts as a fast, low-power address decoder that asserts chip-select (CS) signals synchronously with address setup. Use Value: 10-ns tpd ensures CS assertion occurs well within typical 70-ns SRAM access windows, eliminating wait states. |
Use Scenario: Routing UART, SPI, I²C, and GPIO control signals to four distinct sensor modules on a single PCB. IC Role / Device Role / Timing Role: SN74HCT139PWT functions as a demultiplexer, enabling one controller port to manage four isolated peripheral buses. Use Value: ±4-mA drive capability directly drives enable inputs of level translators or bus switches without added buffers. |
| Industrial I/O Expansion | Legacy System Interface |
|
Use Scenario: Expanding discrete output capability of a PLC CPU module to drive eight solenoid valves via two SN74HCT139PWT units. IC Role / Device Role / Timing Role: SN74HCT139PWT provides synchronous, glitch-free enable gating for solid-state relay drivers in real-time control loops. Use Value: Low input current (≤1 µA) prevents loading of open-collector CPU output pins used for A/B/G control signals. |
Use Scenario: Interfacing a modern FPGA I/O bank (3.3-V tolerant) to legacy 5-V TTL backplane logic in test equipment. IC Role / Device Role / Timing Role: SN74HCT139PWT serves as a level-adapted decoder, accepting 3.3-V CMOS inputs while driving 5-V TTL loads. Use Value: TTL-compatible input thresholds ensure reliable recognition of 3.3-V logic highs without external pull-ups or clamping diodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual decoder/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC139DR | Same logic function and pinout, but HC-family: wider 2–6 V supply range, higher 12 ns tpd, lower 5.2-mA drive. | Suitable for mixed-voltage systems (e.g., 3.3-V MCU + 5-V peripherals) but not drop-in for strict 5-V TTL timing budgets. | Select SN74HC139DR only if supply flexibility outweighs need for 10-ns speed and ±4-mA drive. |
| 74LV139PW | LV-family: 1–5.5 V operation, 7.5 ns tpd, 12-mA drive, but input thresholds fixed at 30%/70% of VCC-not TTL-compatible. | Requires level-shifting for legacy TTL inputs; superior drive and speed benefit new 3.3-V designs with clean rail margins. | Choose 74LV139PW for high-speed 3.3-V systems where input compatibility with 5-V sources is not required. |
Compared with SN74HCT139PWT, SN74HC139DR trades speed and drive strength for broader voltage tolerance, while 74LV139PW delivers faster switching and stronger outputs but loses TTL input compatibility-making SN74HCT139PWT optimal for legacy 5-V systems demanding precise timing and load drive.
Availability
SN74HCT139PWT is available at Aetrix Electronics and suitable for industrial control panels, legacy test instrumentation, and 5-V embedded data acquisition systems requiring stable component supply across long production lifecycles.
Supply support for SN74HCT139PWT 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 ICs, with decades of heritage in industry-standard logic families.
The SN74HCT139PWT belongs to TI's HCT logic series-designed specifically for high-speed memory decoding and data-routing applications where TTL compatibility, low power, and nanosecond propagation delays are essential.
FAQ
What is the operating voltage range for SN74HCT139PWT?
The SN74HCT139PWT operates over 4.5 V to 5.5 V. This narrow range ensures robust noise immunity and full TTL compatibility while maintaining low ICC. Operation outside this window risks undefined logic states or excessive ICC-TI specifies absolute maximum VCC as 7 V, but functional operation is guaranteed only within the recommended 4.5–5.5 V band.
Does SN74HCT139PWT support cascading for larger decode functions?
Yes, SN74HCT139PWT supports cascading via its dual active-low enable inputs (G1 and G2). One decoder's output can drive G of another SN74HCT139PWT to build 3-to-8 or 4-to-16 decoders. The datasheet explicitly states this capability simplifies cascading, and the function table confirms G controls output enable state independently per section.
Can SN74HCT139PWT drive standard LSTTL loads directly?
Yes, SN74HCT139PWT can drive up to 10 LSTTL loads per output, verified by its ±4-mA output drive specification at 5 V and VOH/VOL limits meeting LSTTL voltage thresholds. This eliminates need for external buffer stages in typical memory or peripheral decode applications.
What is the propagation delay of SN74HCT139PWT under typical conditions?
SN74HCT139PWT has a typical propagation delay (tpd) of 10 ns at VCC = 5 V with CL = 50 pF, as specified in Section 6.5 of the datasheet. Maximum tpd is 40 ns at 5.5 V and 43 ns at 4.5 V-ensuring predictable timing margins in high-speed 5-V systems.
Is SN74HCT139PWT pin-compatible with other 16-pin decoder ICs like SN74LS139?
No, SN74HCT139PWT is not pin-compatible with SN74LS139. While both are dual 2-to-4 decoders, SN74LS139 uses different pin assignments-for example, SN74LS139 places Y0–Y3 on pins 1, 2, 3, 4, whereas SN74HCT139PWT maps them across pins 4, 5, 6, 7 and 12, 13, 14, 9. Physical layout and signal routing must be redesigned for substitution.
SN74HCT139PWT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-TSSOP
SN74HCT139PWT FAQ
1.How can I place an order for SN74HCT139PWT through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT139PWT 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 SN74HCT139PWT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT139PWT is usually 5 days.
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Once your SN74HCT139PWT 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 SN74HCT139PWT?
For technical support, including SN74HCT139PWT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT139PWT requirements.
6.How does Aetrix verify that SN74HCT139PWT is sourced from the original manufacturer or authorized distributors?
All SN74HCT139PWT 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 SN74HCT139PWT meets industry standards.
7.What is the process for return or replacement of SN74HCT139PWT?
All SN74HCT139PWT units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT139PWT, 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 SN74HCT139PWT part is unused and in its original packaging.
Return procedure for SN74HCT139PWT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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