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Texas Instruments SN74LS139ADR
- Part No.:
- SN74LS139ADR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74LS139ADR.pdf
- Description:
- IC DECODER/DEMUX 1X2:4 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:5,986
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Product details
Overview
SN74LS139ADR from Texas Instruments is a dual 2-line-to-4-line decoder/demultiplexer in a 16-pin SOIC package, operating from 4.75 V to 5.25 V with typical propagation delay of 15 ns at VCC = 5 V and TA = 25 °C, used for address decoding in microprocessor systems and memory selection logic.
For engineers reviewing the SN74LS139ADR datasheet, SN74LS139ADR pinout, SN74LS139ADR application, or SN74LS139ADR equivalent, this page delivers verified functional specifications, validated pin assignments, confirmed industrial temperature range (0 °C to 70 °C), RoHS-compliant NIPDAU lead finish, and Level-1 MSL rating for reflow compatibility.
Technical Context
The SN74LS139ADR implements two independent 2-to-4 line decoders, each with active-low enable (G̅) and active-low outputs (Y0–Y3). Each decoder accepts two binary inputs (A, B) and generates four mutually exclusive low-active outputs.
It uses standard TTL logic levels: VIH = 2.0 V min, VIL = 0.8 V max, IOH = –0.4 mA at VOH = 2.4 V, and IOL = 8 mA at VOL = 0.5 V - ensuring interoperability with legacy LS-TTL and compatible families.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | LS-TTL - ensures backward compatibility with 74LS series, lower power than standard TTL, and defined noise margins. |
| Supply Voltage | 4.75 V to 5.25 V - requires stable +5 V rail; operation outside this range risks undefined output states. |
| Propagation Delay | 15 ns typical (G̅ to Y, VCC = 5 V, TA = 25 °C) - determines maximum clock rate in synchronous decode paths. |
| Output Drive | 8 mA sink / –0.4 mA source - supports direct interface to multiple LS-TTL inputs without buffering. |
| Operating Temperature | 0 °C to 70 °C - qualified for commercial-grade embedded control and instrumentation applications. |
| Package | SOIC (D) with 16 pins - surface-mount footprint compatible with automated assembly and IPC-7351 land patterns. |
| Moisture Sensitivity | Level-1 (260 °C, unlimited floor life) - eliminates bake requirement prior to reflow soldering. |
Pinout & Package
SN74LS139ADR is housed in a 16-pin Small Outline Integrated Circuit (SOIC) package with 1.27 mm pitch, 7.5 mm body width, and 2.00 mm max height per TI package drawing D.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15 | Decoder 1 & 2 Enable (G̅) | Active-low chip select; both must be low for respective decoder outputs to respond to inputs. |
| 2, 3, 5, 6 | Decoder 1 Inputs (A1, B1, G̅1) & Outputs (Y10–Y13) | First decoder: A1/B1 accept binary address; Y10–Y13 drive low on match; all outputs high when G̅1 high. |
| 8, 10, 11, 12 | Decoder 2 Inputs (A2, B2, G̅2) & Outputs (Y20–Y23) | Second independent decoder with identical timing and drive; enables parallel address decoding. |
| 7, 14 | GND / VCC | Ground reference and +5 V supply - require local 0.1 µF bypass capacitor per TI layout guidelines. |
| 4, 9, 13, 16 | Outputs (Y10–Y13, Y20–Y23) | Open-collector compatible (with pull-up); active-low assertion enables memory or peripheral selection. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent decoders | Enables simultaneous decoding of two separate 2-bit address buses - reduces component count in multi-peripheral systems. |
| Active-low enable & outputs | Directly interfaces with common enable lines and active-low chip-select inputs of SRAM, EPROM, and peripheral ICs. |
| LS-TTL compatible thresholds | Guarantees reliable switching with legacy 74LS, 74ALS, and 74F families without level-shifting circuitry. |
| 15 ns propagation delay | Supports address decode cycles up to ~40 MHz in non-critical timing paths with margin. |
| SOIC packaging with Level-1 MSL | Eliminates moisture sensitivity handling overhead and supports high-yield SMT reflow in volume production. |
Applications
| Memory Address Decoding | Peripheral Selection Logic |
|---|---|
Use Scenario: Selecting one of four 8K×8 SRAM chips in a microcontroller-based data acquisition system using A15–A14 as address bits. IC Role / Device Role / Timing Role: SN74LS139ADR acts as a 2-bit address decoder, asserting individual chip-select lines based on upper address bits. Use Value: Reduces external logic count by replacing discrete NAND gates; maintains deterministic 15 ns decode latency across all four outputs. | Use Scenario: Enabling UART, SPI flash, ADC, and DAC peripherals via dedicated chip-select signals driven from a single microcontroller port. IC Role / Device Role / Timing Role: SN74LS139ADR provides four independent, mutually exclusive active-low enables synchronized to address strobes. Use Value: Eliminates software-controlled GPIO toggling delays; ensures hardware-level peripheral isolation and glitch-free selection. |
| I/O Port Expansion | Legacy Bus Interface |
Use Scenario: Expanding a Z80 CPU's I/O space to support eight discrete I/O latches using A1–A0 and IORQ̅ signal. IC Role / Device Role / Timing Role: SN74LS139ADR decodes I/O address lines under IORQ̅ control to generate latch-enable pulses. Use Value: Enables full use of Z80's 256-port address space with precise timing alignment to bus control signals. | Use Scenario: Interfacing modern FPGA-based controllers with vintage 74LS-based backplane systems requiring TTL-compatible decode logic. IC Role / Device Role / Timing Role: SN74LS139ADR serves as a drop-in replacement for obsolete 74LS139 variants in field-replaceable modules. Use Value: Maintains identical pinout, timing, and drive strength - no PCB or firmware changes required during repair or upgrade. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual 2-to-4 line decoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS139AN | Same logic function and electrical specs, but in 16-pin PDIP package with through-hole mounting and NIPDAU finish. | Used where manual prototyping, socket-based testing, or legacy through-hole assembly is required. | Select SN74LS139AN for breadboarding, lab validation, or mixed-technology boards with through-hole components. |
| SN74HC139DR | CMOS version with wider supply range (2 V–6 V), higher speed (21 ns typ), and lower ICC, but incompatible input thresholds (VIH = 3.5 V min @ VCC = 6 V). | Suitable for battery-powered or mixed-voltage systems, but requires level translation when interfacing with LS-TTL outputs. | Choose SN74HC139DR only when upgrading to CMOS logic family; verify input compatibility with driving devices before substitution. |
Compared with SN74LS139AN and SN74HC139DR, the SN74LS139ADR offers optimal balance of LS-TTL compatibility, surface-mount manufacturability, and commercial-temperature reliability - making it the preferred choice for new SMT-based industrial control designs requiring proven legacy interface behavior.
Availability
SN74LS139ADR is available at Aetrix Electronics and suitable for memory address decoding, peripheral selection logic, I/O port expansion, and legacy bus interface applications requiring stable component supply and long-term industrial availability.
Supply support for SN74LS139ADR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74LS139ADR belongs to TI's legacy 74LS logic family, designed specifically for robust, low-power, TTL-compatible digital interfacing in commercial-grade embedded systems and retro-computing platforms.
FAQ
What is the maximum operating frequency supported by SN74LS139ADR?
The SN74LS139ADR does not specify a maximum clock frequency because it is a combinational logic device without internal clocking. Its usable switching rate depends on propagation delay (15 ns typical) and system-level timing margins. In practice, SN74LS139ADR reliably supports address decode operations up to approximately 40 MHz in well-designed layouts with controlled trace lengths and proper decoupling.
Can SN74LS139ADR drive LEDs directly?
Yes, SN74LS139ADR can drive LEDs directly when configured with active-low outputs and appropriate current-limiting resistors. Each output sinks up to 8 mA at VOL ≤ 0.5 V, sufficient for low-current indicator LEDs. For example, a 330 Ω resistor with a 5 V supply yields ~12 mA - so a 470 Ω resistor is recommended to stay within SN74LS139ADR's 8 mA limit while providing visible LED brightness.
Is SN74LS139ADR pin-compatible with SN74LS139AN?
Yes, SN74LS139ADR is pin-compatible with SN74LS139AN. Both share identical 16-pin numbering, function assignment, and logic behavior. The only differences are package type (SOIC vs. PDIP), thermal characteristics, and mounting method - allowing direct substitution in existing designs when transitioning from through-hole to surface-mount assembly.
Does SN74LS139ADR support mixed-voltage operation?
No, SN74LS139ADR operates strictly within 4.75 V to 5.25 V. It is not designed for mixed-voltage or level-shifting applications. Input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V) and output drive capability are specified only at VCC = 5 V. Using SN74LS139ADR outside this range may result in incorrect logic states or degraded noise immunity.
What is the meaning of "LS139A" marking on SN74LS139ADR?
The "LS139A" marking on SN74LS139ADR is the standardized device identifier laser-etched on the package body, confirming its identity as a 74LS-series dual 2-to-4 line decoder. This marking aligns with TI's industry-standard part labeling convention and matches the functional designation used in schematics and BOMs referencing the SN74LS139ADR.
SN74LS139ADR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- 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:
- 400µA, 8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74LS139ADR FAQ
1.How can I place an order for SN74LS139ADR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS139ADR 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 SN74LS139ADR reliable?
The price and inventory of SN74LS139ADR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS139ADR is usually 5 days.
3.What payment methods are accepted for SN74LS139ADR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS139ADR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS139ADR?
SN74LS139ADR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS139ADR 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 SN74LS139ADR?
For technical support, including SN74LS139ADR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS139ADR requirements.
6.How does Aetrix verify that SN74LS139ADR is sourced from the original manufacturer or authorized distributors?
All SN74LS139ADR 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 SN74LS139ADR meets industry standards.
7.What is the process for return or replacement of SN74LS139ADR?
All SN74LS139ADR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS139ADR, 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 SN74LS139ADR part is unused and in its original packaging.
Return procedure for SN74LS139ADR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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