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Texas Instruments 74AC11138D
- Part No.:
- 74AC11138D
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
74AC11138D.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,257
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Product details
Overview
74AC11138D from Texas Instruments is a 3-line to 8-line decoder/demultiplexer in SOIC-16 package, designed for high-speed memory decoding and data routing. It features three enable inputs (G1 active-high, G2A/G2B active-low), propagation delays as low as 5.1 ns at 5 V, operates from –40°C to 85°C, and supports VCC = 3–5.5 V. It is used in memory address decoding subsystems where minimal system delay is critical.
For engineers reviewing the 74AC11138D datasheet, 74AC11138D pinout, 74AC11138D application, or 74AC11138D equivalent, this page delivers verified functional modes, switching characteristics at both 3.3 V and 5 V, thermal resistance (RθJA = 130°C/W), latch-up immunity (500 mA at 125°C), and precise pin-level circuit roles - all confirmed for the D-package variant.
Technical Context
The 74AC11138D implements positive-logic decoding with binary-select inputs A/B/C and three independent enables (G1, G2A, G2B) enabling cascaded 24- or 32-line decoding without external inverters. Its EPIC™ 1-µm CMOS process ensures high noise immunity and stable operation across industrial temperature range.
Functional mode selection relies on simultaneous evaluation of all three enable states: only when G1 = HIGH and G2A = G2B = LOW does the device decode A/B/C to assert exactly one of eight Y0–Y7 outputs LOW (active-low outputs). All outputs remain HIGH otherwise - a feature critical for bus arbitration and hierarchical enable trees.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 3 V to 5.5 V - supports dual-supply systems and legacy 5 V TTL-compatible interfaces while enabling lower-power 3.3 V operation. |
| tPLH / tPHL (5 V) | 5.1–8.8 ns - ensures sub-10 ns propagation delay for high-speed memory access timing budgets. |
| IOH / IOL (5 V) | –24 mA / +24 mA - drives standard TTL loads directly without buffer stages in mixed-logic systems. |
| ICC (max) | 40 µA at 5.5 V - ultra-low quiescent current enables use in power-sensitive embedded control logic. |
| Operating Temp | –40°C to +85°C - qualified for industrial-grade reliability in non-automotive embedded environments. |
| RθJA | 130°C/W (SOIC-D) - defines thermal derating limits under natural convection; requires no heatsink below 100 mW dissipation. |
| Input Clamping | ±20 mA - protects against transient overvoltage events during hot-plug or ESD-prone board handling. |
Pinout & Package
74AC11138D uses a 16-pin plastic small-outline integrated circuit (SOIC-D) package measuring 9.9 mm × 6.0 mm (body: 9.9 mm × 3.9 mm), with center-aligned VCC (pin 12) and GND (pin 4) to minimize high-speed switching noise.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Y1) | Data output | Active-low decoded output corresponding to A=0,B=0,C=1; sinks up to 24 mA at 5 V. |
| 2 (Y2) | Data output | Active-low decoded output for A=0,B=1,C=0; shares same enable logic and drive strength as Y1. |
| 3 (Y3) | Data output | Active-low output for A=0,B=1,C=1; enables compact 3-bit address decoding in memory arrays. |
| 4 (GND) | Power reference | Primary ground return path; center placement reduces ground bounce in high-frequency switching. |
| 5–8 (Y4–Y7) | Data outputs | Active-low outputs covering remaining 4 combinations of A/B/C; collectively support full 3-to-8 decode map. |
| 9 (G2B) | Enable input | Active-low cascade enable; tied LOW to activate decoding, HIGH to force all outputs HIGH. |
| 10 (G2A) | Enable input | Second active-low enable; used with G2B to simplify multi-chip decoding trees without inverters. |
| 11 (G1) | Enable input | Active-high primary enable; provides orthogonal control for hierarchical chip select architectures. |
| 12 (VCC) | Supply | Center-placed 3–5.5 V supply pin; minimizes supply loop inductance and improves PSRR at high frequencies. |
| 13–15 (C,B,A) | Select inputs | Binary address inputs (LSB→MSB order); accept TTL/CMOS logic levels across full VCC range. |
| 16 (Y0) | Data output | Active-low output for A=B=C=0; completes full 8-output decode set with deterministic LOW/HIGH states. |
Key Features
| Feature | Design Value |
|---|---|
| Three enable inputs | Enables 24-line decoding without external inverters and 32-line decoding with only one inverter - reducing BOM count and layout area. |
| Center-pin VCC/GND | Reduces simultaneous switching noise by shortening high-current supply/return paths - critical for stable operation in dense logic arrays. |
| EPIC™ 1-µm CMOS | Delivers 5× faster speed than standard AC logic while maintaining compatibility with existing 74AC family PCB footprints and drive requirements. |
| 500-mA latch-up immunity | Guarantees robustness against transient current surges up to 125°C - essential for industrial systems with unregulated power rails or thermal cycling. |
| Active-low outputs | Directly interfaces with common memory chip-select (CS#) and peripheral enable (EN#) inputs without level-shifting or inversion logic. |
Applications
| Memory Address Decoding | Bus Multiplexing |
|---|---|
Use Scenario: Selecting one of eight SRAM or ROM chips in a 64 KB memory bank using 16-bit address bus. IC Role / Device Role / Timing Role: Primary address decoder mapping A13–A15 to chip-select lines; operates within memory access timing budget. Use Value: Propagation delay ≤8.8 ns at 5 V ensures negligible impact on overall memory cycle time - preserving system throughput. |
Use Scenario: Routing UART, SPI, or I²C signals between microcontroller and multiple peripherals via shared bus lines. IC Role / Device Role / Timing Role: Demultiplexer enabling one peripheral at a time; G1/G2A/G2B used for software-controlled channel selection. Use Value: Three independent enables allow flexible priority-based or round-robin bus arbitration without additional logic gates. |
| Cascaded Logic Expansion | Industrial Control I/O Selection |
Use Scenario: Building a 32-line decoder for PLC backplane addressing using two 74AC11138D devices. IC Role / Device Role / Timing Role: Master-slave configuration where upper address bits control G1/G2 enables of subordinate decoders. Use Value: Eliminates need for external inverters in 32-line expansion - reducing component count and signal integrity risk. |
Use Scenario: Enabling discrete sensor inputs or actuator outputs in modular industrial I/O modules. IC Role / Device Role / Timing Role: Output-enable controller selecting one of eight analog input channels for ADC sampling sequence. Use Value: Active-low outputs directly drive enable pins of analog switches or multiplexers rated for ±15 V signal ranges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-to-8 decoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC138N | Slower propagation (21 ns @ 5 V), higher RθJA (110°C/W), no latch-up immunity spec, HC-series CMOS. | Suitable for cost-sensitive, low-speed control logic but not high-speed memory systems requiring <10 ns delay. | Choose SN74HC138N only if timing budget allows ≥2× longer propagation delay and industrial temp range is not required. |
| 74ACT138D | Same pinout and function, but ACT series offers TTL-compatible inputs (VIH = 2 V min) and slightly faster tPLH (4.5 ns @ 5 V). | Better suited for mixed-voltage systems interfacing with legacy TTL logic, though higher ICC (100 µA max). | Prefer 74ACT138D when driving legacy 5 V TTL loads or when tighter timing margins demand sub-5 ns delay. |
Compared with SN74HC138N and 74ACT138D, the 74AC11138D uniquely balances 5.1 ns speed, 500 mA latch-up immunity, and industrial temperature rating - making it optimal for memory subsystems where reliability under transient stress and tight timing coexist.
Availability
74AC11138D is available at Aetrix Electronics and suitable for memory address decoding, bus demultiplexing, industrial I/O selection, and cascaded logic expansion requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 74AC11138D 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 innovation in high-reliability digital ICs.
The 74AC11138D belongs to TI's advanced CMOS logic portfolio, engineered specifically for high-speed memory-decoding and data-routing applications demanding minimal propagation delay and robust noise immunity.
FAQ
What is the maximum operating voltage for the 74AC11138D?
The 74AC11138D supports a supply voltage range of 3 V to 5.5 V, with absolute maximum VCC rated at 7 V. Operation above 5.5 V violates recommended conditions and risks parametric degradation or permanent damage. The 74AC11138D is optimized for stable performance at 3.3 V and 5 V nominal rails, delivering specified tPLH/tPHL and drive strength only within that range.
Does the 74AC11138D have active-high or active-low outputs?
The 74AC11138D features active-low outputs (Y0–Y7): only the selected output goes LOW while all others remain HIGH. This matches standard memory chip-select (CS#) and peripheral enable (EN#) conventions. The 74AC11138D does not provide active-high outputs - polarity is fixed per its logic diagram and function table.
Can the 74AC11138D be used in a 3.3 V system?
Yes, the 74AC11138D is fully specified for 3.3 V operation (VCC = 3.3 V ± 0.3 V), with propagation delays as low as 7.2 ns and output drive capability of ±12 mA. Its VIH/VIL thresholds scale with VCC, ensuring reliable logic recognition of 3.3 V CMOS inputs. The 74AC11138D maintains full functionality and timing compliance at 3.3 V without level shifters.
What is the thermal resistance (RθJA) of the 74AC11138D in SOIC-D package?
The 74AC11138D in SOIC-D package has a junction-to-ambient thermal resistance (RθJA) of 130°C/W under standard JEDEC test conditions. This value assumes no copper pour or airflow; actual board-level thermal performance depends on PCB copper area, layer stackup, and ambient conditions. The 74AC11138D remains within safe operating limits below ~100 mW total power dissipation in typical layouts.
How many enable inputs does the 74AC11138D have, and what are their polarities?
The 74AC11138D has three enable inputs: G1 (active-high), G2A (active-low), and G2B (active-low). All three must be asserted simultaneously (G1 = HIGH, G2A = G2B = LOW) for decoding to occur. This configuration enables flexible cascading - for example, using G1 as master enable and G2A/G2B as subordinate selects - without external gate logic.
74AC11138D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 3:8
- Independent Circuits:
- 1
- Current - Output High, Low:
- 24mA, 24mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 3V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
74AC11138D FAQ
1.How can I place an order for 74AC11138D through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AC11138D 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 74AC11138D reliable?
The price and inventory of 74AC11138D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AC11138D is usually 5 days.
3.What payment methods are accepted for 74AC11138D?
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4.How is shipping managed for 74AC11138D?
74AC11138D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AC11138D 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 74AC11138D?
For technical support, including 74AC11138D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AC11138D requirements.
6.How does Aetrix verify that 74AC11138D is sourced from the original manufacturer or authorized distributors?
All 74AC11138D 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 74AC11138D meets industry standards.
7.What is the process for return or replacement of 74AC11138D?
All 74AC11138D units undergo pre-shipment inspection (PSI). If there is an issue with 74AC11138D, 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 74AC11138D part is unused and in its original packaging.
Return procedure for 74AC11138D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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