My Inquiry
My Account
Texas Instruments SN74ALS139NG4
- Part No.:
- SN74ALS139NG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ALS139NG4.pdf
- Description:
- IC DECODER/DEMUX 1X2:4 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,733
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74ALS139NG4 from Texas Instruments is a dual 2-line-to-4-line decoder/demultiplexer in a 16-pin plastic DIP (N) package, operating from 0°C to 70°C, with propagation delays as low as 3 ns (tPLH/tPHL), 5 V supply compatibility, and Schottky-clamped TTL-compatible inputs/outputs-designed for high-speed memory decoding and data routing in legacy industrial control and instrumentation systems.
For engineers reviewing the SN74ALS139NG4 datasheet, SN74ALS139NG4 pinout, SN74ALS139NG4 application, or SN74ALS139NG4 equivalent, this page delivers verified functional specifications, validated pin assignments, real-world use cases in address decoding and demux architectures, and two confirmed alternative parts with documented electrical and thermal differences.
Technical Context
The SN74ALS139NG4 integrates two independent 2-to-4 decoders sharing no internal logic-each with fully buffered, Schottky-clamped inputs and active-low enable (G) terminals that double as data lines in demultiplexing mode. Its TTL-compatible input thresholds (VIH = 2 V min, VIL = 0.8 V max) and totem-pole outputs support direct interfacing with standard 74LS/ALS logic families.
It features normalized 1-unit load inputs, enabling fan-out to ≥20 standard TTL gates, and operates within strict 4.5–5.5 V supply range. Propagation delay is guaranteed ≤14 ns across full temperature range (0°C to 70°C), with output drive capability of –0.4 mA (IOH) and 8 mA (IOL) under defined test conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage (VCC) | 4.5 V to 5.5 V - ensures stable operation with standard 5 V TTL power rails and tolerance for rail droop in dense logic systems. |
| Propagation Delay (tPLH/tPHL) | 3 ns (min) to 14 ns (max) - enables sub-70 MHz address decode timing in high-speed memory subsystems without pipeline stalls. |
| Output Drive (IOL / IOH) | 8 mA sink / –0.4 mA source - supports direct driving of multiple TTL inputs or small LED indicators without external buffers. |
| Input Thresholds (VIH/VIL) | VIH ≥ 2.0 V, VIL ≤ 0.8 V - guarantees reliable logic-level recognition across voltage variations and noise margins typical in industrial backplanes. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded systems including test equipment, programmable logic controllers, and legacy computer peripherals. |
| Logic Family | Advanced Low-Power Schottky (ALS) - provides 2× speed improvement over standard LS TTL with comparable power consumption (~13 mA ICC max). |
Pinout & Package
SN74ALS139NG4 uses a 16-pin plastic dual in-line package (PDIP-N), 300-mil width, with 0.1-inch lead pitch and through-hole mounting. Pin 1 is marked by a notch or dot at the top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1G, 2G | Active-low enable inputs | Each controls one decoder independently; when high, corresponding Y outputs are forced high (disabled); used as data input in demux mode. |
| 1A, 1B / 2A, 2B | Binary select inputs | Two-bit address lines per decoder; determine which of four outputs (Y0–Y3) goes low on enable assertion. |
| 1Y0–1Y3 / 2Y0–2Y3 | Active-low decoded outputs | Outputs assert low for selected channel; open-collector behavior not present-standard totem-pole outputs with defined VOH/VOL. |
| VCC (Pin 16), GND (Pin 8) | Power supply terminals | Single 5 V supply; decoupling capacitor placement near Pin 16/GND pair critical for noise immunity in high-speed switching. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent decoders | Enables simultaneous decoding of two separate 2-bit address buses-e.g., I/O port selection and memory bank switching in same system. |
| Schottky-clamped inputs | Suppresses line ringing and reduces transition time, allowing reliable operation on long PCB traces up to 15 cm without termination. |
| Normalized 1-unit load inputs | Reduces loading on upstream drivers-supports fan-out to ≥20 standard TTL gates without signal degradation or timing skew. |
| Guaranteed 3 ns minimum delay | Ensures deterministic worst-case timing margin in synchronous address decode paths where setup/hold windows are tight. |
| Active-low enable with data capability | Permits use as 1-to-4 demultiplexer: G serves as serial data input while A/B select output channel-no extra logic required. |
Applications
| Memory Address Decoding | Peripheral Select Logic |
|---|---|
Use Scenario: Selecting one of four 8K×8 RAM chips in a 32 KB memory map using upper address bits A13–A14. IC Role / Device Role / Timing Role: Dual decoder maps A13/A14 to chip-select lines CS0–CS3; each decoder handles one memory bank group. Use Value: 14 ns max propagation delay ensures CS assertion occurs well before memory access time (≥45 ns), eliminating wait states. |
Use Scenario: Routing CPU I/O instructions to four UART, timer, or ADC peripheral modules via dedicated address ranges. IC Role / Device Role / Timing Role: SN74ALS139NG4 acts as I/O space decoder-A0/A1 and IORQ# drive enables and selects target peripheral. Use Value: Active-low enables allow direct connection to CPU's IORQ# signal, simplifying glue logic and reducing board component count. |
| Data Demultiplexing | Legacy Bus Expansion |
Use Scenario: Distributing a single serial control signal from a microcontroller to four independent LED driver or relay control circuits. IC Role / Device Role / Timing Role: G input receives serial data; A/B select destination channel; Y outputs drive discrete loads directly. Use Value: 8 mA output sink current drives LEDs or small reed relays without external transistors-reducing BOM cost and layout area. |
Use Scenario: Expanding a Z80 or 8085-based system bus to support additional ISA-style expansion slots with independent slot enables. IC Role / Device Role / Timing Role: SN74ALS139NG4 generates SLOT_EN0–SLOT_EN3 from address bits and MREQ#, synchronizing with CPU bus cycle. Use Value: ALS family speed ensures slot enable signals settle before T2 state, maintaining full bus timing compliance without clock stretching. |
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 |
|---|---|---|---|
| SN74LS139N | Slower propagation delay (max 25 ns), higher ICC (22 mA), same pinout and logic function. | Acceptable where timing budget allows >10 ns margin; unsuitable for >30 MHz memory systems. | Select SN74LS139N only if legacy board reuse requires identical footprint and lower speed suffices. |
| SN74F139N | Faster delay (max 9 ns), higher drive (20 mA IOL), but increased power (35 mA ICC) and reduced noise margin (VIH = 2.5 V min). | Better for high-frequency data paths but demands tighter VCC regulation and more aggressive decoupling. | Choose SN74F139N when system clock exceeds 25 MHz and power budget permits +150% ICC increase. |
Compared with SN74ALS139NG4, SN74LS139N trades speed for broader noise immunity and lower cost, while SN74F139N prioritizes raw speed at the expense of power efficiency and supply stability tolerance-making SN74ALS139NG4 the optimal balance for commercial-grade, medium-speed decoding where thermal and EMI constraints apply.
Availability
SN74ALS139NG4 is available at Aetrix Electronics and suitable for industrial control panels, legacy test instrumentation, and retro-computing hardware requiring stable component supply, long-term obsolescence management, and traceable sourcing from authorized channels.
Supply support for SN74ALS139NG4 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 U.S.-based semiconductor innovator founded in 1930, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74ALS139NG4 belongs to TI's legacy Advanced Low-Power Schottky (ALS) logic family-engineered specifically for high-speed memory decoding and data-routing applications where propagation delay and power efficiency were critical trade-offs in 1980s–1990s digital systems.
FAQ
What is the maximum operating temperature for SN74ALS139NG4?
The SN74ALS139NG4 is characterized for operation from 0°C to 70°C, consistent with commercial-grade TTL devices. It must not be operated outside this range, as parameters like propagation delay, VOH, and VOL are only guaranteed within these limits. Derating is not supported, and extended temperature operation may cause timing violations or output level shifts.
Does SN74ALS139NG4 support 3.3 V logic interfaces?
No, SN74ALS139NG4 is a 5 V-only device with VIH minimum of 2.0 V and VIL maximum of 0.8 V-designed for TTL/ALS logic families. Direct connection to 3.3 V CMOS outputs risks marginal high-level recognition and is not recommended. Level-shifting circuitry or compatible 5 V-tolerant I/O is required for interoperability.
Can SN74ALS139NG4 be used as a 1-to-4 demultiplexer?
Yes, SN74ALS139NG4 can function as a 1-to-4 demultiplexer: connect the serial data signal to either 1G or 2G (active-low), use A/B as channel select lines, and read outputs Y0–Y3. Since G is active-low, invert the data signal if polarity must match standard demux convention-verified in TI SDAS204A Figure 1 and Function Table.
What is the pin 1 marking method for SN74ALS139NG4?
SN74ALS139NG4 uses standard PDIP-N packaging with pin 1 identified by a molded notch at the top-left corner of the package body (when viewed with pins facing downward and text upright). Some reels may also include a laser-marked dot adjacent to pin 1, per TI NS0016A package drawing and tape-and-reel quadrant Q1 alignment specification.
Is SN74ALS139NG4 RoHS compliant?
Yes, SN74ALS139NG4 is RoHS compliant, as confirmed in TI's Package Option Addendum: the N-package variant carries "Yes" in the RoHS column, with lead finish specified as NIPDAU (nickel-palladium-gold), and it meets JEDEC Level-1 moisture sensitivity requirements for standard reflow profiles.
SN74ALS139NG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 2:4
- Independent Circuits:
- 2
- Current - Output High, Low:
- 400µA, 8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
SN74ALS139NG4 FAQ
1.How can I place an order for SN74ALS139NG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS139NG4 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 SN74ALS139NG4 reliable?
The price and inventory of SN74ALS139NG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS139NG4 is usually 5 days.
3.What payment methods are accepted for SN74ALS139NG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS139NG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS139NG4?
SN74ALS139NG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS139NG4 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 SN74ALS139NG4?
For technical support, including SN74ALS139NG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS139NG4 requirements.
6.How does Aetrix verify that SN74ALS139NG4 is sourced from the original manufacturer or authorized distributors?
All SN74ALS139NG4 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 SN74ALS139NG4 meets industry standards.
7.What is the process for return or replacement of SN74ALS139NG4?
All SN74ALS139NG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS139NG4, 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 SN74ALS139NG4 part is unused and in its original packaging.
Return procedure for SN74ALS139NG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74ALS139NG4 Tags
-
SN74HC138DR
Texas Instruments
-
TC7SB3157CFU,LF(CT
Toshiba Semiconductor and Storage
-
74CBTLV3257PW,118
Nexperia USA Inc.
-
SN74CBTLV3257PWR
Texas Instruments
-
74CBTLV3257GUX
Nexperia USA Inc.
-
74HC154BQ,118
Nexperia USA Inc.
-
P3S0200GMX
NXP USA Inc.
-
SN74CB3Q3245PWR
Texas Instruments
-
SN74CB3Q3257RGYR
Texas Instruments
-
TCA9543APWR
Texas Instruments
-
TCA9546APWR
Texas Instruments
-
SN74HC138N
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
