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Texas Instruments SN74LVC138AQDREP
- Part No.:
- SN74LVC138AQDREP
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74LVC138AQDREP.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,268
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Product details
Overview
SN74LVC138AQDREP from Texas Instruments is a 3-line to 8-line decoder/demultiplexer in SOIC-16 package, operating from 2 V to 3.6 V with 5.8 ns max propagation delay at 3.3 V, 5.5 V-tolerant inputs, and designed for high-speed memory decoding in defense/aerospace systems.
For engineers reviewing the SN74LVC138AQDREP datasheet, SN74LVC138AQDREP pinout, SN74LVC138AQDREP application, or SN74LVC138AQDREP equivalent, this device serves as a low-voltage, high-speed address decoder with three enable inputs (G1, G2A, G2B) enabling scalable demultiplexing and mixed-voltage translation in harsh-environment embedded systems.
Technical Context
The SN74LVC138AQDREP implements active-low dual-enable (G2A, G2B) and active-high single-enable (G1) logic to select one of eight inverted outputs (Y0–Y7) based on binary inputs A, B, C. Its LVC-family CMOS process ensures rail-to-rail output swing and 5.5 V input tolerance without level shifters.
Propagation delay is tightly specified across temperature (–40°C to 125°C) and supply (2.7 V–3.6 V), with typical ground bounce (VOLP) < 0.8 V and undershoot (VOHV) > 2 V at 3.3 V - critical for signal integrity in fast enable-controlled memory subsystems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 3.6 V - supports modern low-power 3.3 V systems while maintaining compatibility with 2.7 V minimum operation. |
| Max tpd | 5.8 ns at VCC = 3.3 V - enables integration into sub-10 ns memory access cycles without adding system-level latency. |
| Input Voltage Tolerance | Up to 5.5 V - allows direct interfacing with legacy 5 V logic without external level translators. |
| Output Drive | ±24 mA at VCC = 3 V - sufficient to drive multiple LVC/LVT inputs or small capacitive loads in routing applications. |
| Operating Temp | –40°C to +125°C - qualified for extended industrial and defense-grade environments per EP (Enhanced Product) specification. |
| ESD Rating | >2000 V HBM, >200 V MM - meets MIL-STD-883 requirements for ruggedized deployment in aerospace platforms. |
| Power Dissipation Cap | 26 pF at 10 MHz - enables accurate dynamic power estimation in high-density PCB layouts. |
Pinout & Package
SN74LVC138AQDREP is housed in a 16-pin SOIC (D) package with 1.27 mm pitch, 10.3 mm body width, and 6.5 mm body length per TI PW0016A outline. Pin 1 index area located at top-left corner (quadrant Q1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| G1 | Active-high enable input | Enables decoding only when high; used with G2A/G2B to reduce external gating in cascaded configurations. |
| G2A, G2B | Active-low enable inputs | Both must be low to activate outputs; permits 24-line decoding without inverters and 32-line with one inverter. |
| A, B, C | Binary address select inputs | 3-bit code selects one of eight outputs; inputs accept 5.5 V signals for mixed-voltage system interfacing. |
| Y0–Y7 | Inverted active-low decoded outputs | Each output goes low when selected; open-drain behavior not supported - outputs are push-pull CMOS. |
| VCC, GND | Power supply terminals | Single 2–3.6 V supply; decoupling required within 10 mm due to fast switching transients (VOLP/VOHV specs). |
Key Features
| Feature | Design Value |
|---|---|
| 3.3 V optimized propagation delay | 5.8 ns max at 3.3 V enables use in high-speed memory decode paths where timing margin is constrained. |
| 5.5 V tolerant inputs | Eliminates need for external level shifters when interfacing with 5 V microcontrollers or FPGAs in hybrid voltage systems. |
| Three independent enable inputs | Allows hierarchical expansion to 24- or 32-line decoding with minimal external logic - reduces board space and BOM count. |
| Enhanced Product (EP) qualification | Controlled baseline, extended lifecycle, traceability, and –40°C to 125°C operation meet defense/aerospace reliability mandates. |
| Low ground bounce & undershoot | VOLP < 0.8 V and VOHV > 2 V at 3.3 V ensure clean signal edges in noise-sensitive analog-adjacent or RF-adjacent designs. |
Applications
| Memory Address Decoding | FPGA I/O Expansion |
|---|---|
|
Use Scenario: Selecting one of eight SRAM or Flash memory banks in a radiation-hardened avionics controller. IC Role / Device Role / Timing Role: High-speed address decoder placed between processor bus and memory array, synchronized to clock-enable edge. Use Value: 5.8 ns tpd ensures decoder delay contributes <5% to total 120 ns memory access window, preserving timing margin. |
Use Scenario: Expanding limited FPGA GPIOs to control eight discrete analog switches in a test instrumentation front-end. IC Role / Device Role / Timing Role: Demultiplexer translating 3-bit FPGA output into individual channel enables; G1 used as data input. Use Value: 5.5 V input tolerance allows direct connection to FPGA I/O banks configured at 3.3 V or 5 V, avoiding level-shifter ICs. |
| Avionics Bus Interface | Secure Bootloader Selection |
|
Use Scenario: Routing command signals across redundant ARINC-429 receiver modules in a flight control computer. IC Role / Device Role / Timing Role: Signal router selecting one of eight receiver channels based on mode register bits; G2A/G2B tied to fault flags. Use Value: Dual active-low enables allow fail-safe channel disable via hardware fault lines without software intervention. |
Use Scenario: Selecting between primary and backup bootloader images stored in separate SPI Flash devices during cold start. IC Role / Device Role / Timing Role: Secure boot gatekeeper asserting Y0/Y1 to enable respective Flash CS lines; G1 driven by tamper-detection circuit. Use Value: –40°C to 125°C rating and EP qualification ensure reliable operation during thermal cycling in sealed military enclosures. |
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 |
|---|---|---|---|
| SN74LVC138AQPWREP | TSSOP-16 package (PW), same electrical specs, 12.4 mm reel width, 2000 pcs/reel. | Better thermal performance (θJA = 108°C/W vs. 73°C/W) but lower board-level mechanical robustness than SOIC. | Select when PCB space is constrained and reflow profile accommodates finer-pitch TSSOP. |
| SN74LVC138AMPWTEP | TSSOP-16 with –55°C to 125°C rating, C138AME marking, 250 pcs/reel, same logic function. | Extended temperature range meets MIL-STD-810H Category 12 shock/vibe requirements; smaller reel quantity increases unit cost. | Select for full military-spec deployments where –55°C startup is mandatory and volume is low. |
Compared with SN74LVC138AQDREP, the QPWREP offers footprint reduction at the cost of thermal resistance, while the MPWTEP adds extreme-temperature capability with higher procurement overhead - both retain identical logic behavior and pinout.
Availability
SN74LVC138AQDREP is available at Aetrix Electronics and suitable for defense electronics, aerospace avionics, and medical imaging systems requiring stable component supply across extended product lifecycles.
Supply support for SN74LVC138AQDREP 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and industrial-grade qualification.
The SN74LVC138AQDREP belongs to TI's Enhanced Product (EP) logic family, engineered specifically for mission-critical applications in defense, aerospace, and medical systems where extended temperature operation and controlled manufacturing baselines are mandatory.
FAQ
What is the maximum operating voltage for SN74LVC138AQDREP?
The SN74LVC138AQDREP has an absolute maximum supply voltage (VCC) of 6.5 V, but its recommended operating range is strictly 2 V to 3.6 V. Operation outside this range may cause functional failure or accelerated wear. Inputs tolerate up to 5.5 V regardless of VCC, making SN74LVC138AQDREP suitable for mixed-voltage interfaces without level shifters.
Does SN74LVC138AQDREP support cascading for larger decoder configurations?
Yes, SN74LVC138AQDREP supports cascading via its three enable inputs: G1 (active-high), G2A and G2B (both active-low). Two SN74LVC138AQDREP devices can implement a 24-line decoder without external inverters; a 32-line decoder requires only one inverter. This architecture minimizes external logic and preserves timing predictability in multi-bank memory systems.
What is the meaning of "EP" in SN74LVC138AQDREP?
The "EP" suffix in SN74LVC138AQDREP denotes Texas Instruments' Enhanced Product qualification - a program delivering controlled manufacturing baselines, extended temperature range (–40°C to 125°C), full traceability, extended product life cycle, and compliance with defense/aerospace reliability standards. It is not a catalog or automotive variant, but a dedicated high-reliability offering.
Can SN74LVC138AQDREP be used as a demultiplexer?
Yes, SN74LVC138AQDREP functions as a demultiplexer when one enable input (e.g., G1) is used as the data input while A, B, C serve as select lines. The selected output (Y0–Y7) mirrors the logic state of G1, with inversion inherent to the device's active-low outputs. This eliminates need for external inverters in serial-to-parallel data distribution.
Is SN74LVC138AQDREP RoHS compliant and lead-free?
Yes, SN74LVC138AQDREP is RoHS compliant and features NiPdAu (NIPDAU) lead finish. Its MSL rating is Level-1-260°C-UNLIM, indicating unlimited floor life under dry pack conditions. The SOIC (D) package uses standard JEDEC-compliant reflow profiles, and TI provides full material declaration and exemption documentation upon request.
SN74LVC138AQDREP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 3:8
- Independent Circuits:
- 1
- Current - Output High, Low:
- 24mA, 24mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 3.6V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74LVC138AQDREP FAQ
1.How can I place an order for SN74LVC138AQDREP through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC138AQDREP 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 SN74LVC138AQDREP reliable?
The price and inventory of SN74LVC138AQDREP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC138AQDREP is usually 5 days.
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4.How is shipping managed for SN74LVC138AQDREP?
SN74LVC138AQDREP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC138AQDREP 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 SN74LVC138AQDREP?
For technical support, including SN74LVC138AQDREP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC138AQDREP requirements.
6.How does Aetrix verify that SN74LVC138AQDREP is sourced from the original manufacturer or authorized distributors?
All SN74LVC138AQDREP 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 SN74LVC138AQDREP meets industry standards.
7.What is the process for return or replacement of SN74LVC138AQDREP?
All SN74LVC138AQDREP units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC138AQDREP, 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 SN74LVC138AQDREP part is unused and in its original packaging.
Return procedure for SN74LVC138AQDREP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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