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Texas Instruments SN74LVC138ADRG4
- Part No.:
- SN74LVC138ADRG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74LVC138ADRG4.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,262
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Product details
Overview
SN74LVC138ADRG4 from Texas Instruments is a 3-line to 8-line decoder/demultiplexer IC operating from 1.65 V to 3.6 V, with inputs tolerant up to 5.5 V, 5.8 ns max propagation delay at 3.3 V, and active-low dual-enable plus active-high enable architecture. It serves as a memory address decoder or LED column selector in low-voltage embedded control systems.
For engineers reviewing the SN74LVC138ADRG4 datasheet, SN74LVC138ADRG4 pinout, SN74LVC138ADRG4 application, or SN74LVC138ADRG4 equivalent, key selection criteria include supply voltage range compatibility, enable logic polarity matching, output drive capability (±24 mA), propagation delay budget, and SOIC-16 package footprint constraints.
Technical Context
The SN74LVC138ADRG4 implements a binary-select decoder with three address inputs (A, B, C) and three enables (G1 high-active, G2A/G2B low-active), where only one of eight outputs (Y0–Y7) goes low when all enables are asserted. Its CMOS design ensures rail-to-rail input tolerance and balanced output drive.
Propagation delay varies with supply voltage: 5.8 ns at 3.3 V, 6.4 ns at 2.7 V, and 20.3 ns at 1.8 V. Output skew is ≤1 ns at 3.3 V, supporting synchronous multi-output timing in memory and display subsystems without external gating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.65 V to 3.6 V - supports direct interface with 1.8-V, 2.5-V, and 3.3-V logic domains |
| Input Voltage Tolerance | Up to 5.5 V - enables safe interfacing with legacy 5-V controllers without level shifters |
| Max Propagation Delay | 5.8 ns at VCC = 3.3 V - meets tight timing budgets in high-speed memory decoding |
| Output Drive Strength | ±24 mA at VCC = 3.0 V - sufficient for direct LED column sinking or bus loading |
| Enable Logic Configuration | G1 (active-high), G2A/G2B (active-low) - reduces external inverters needed for cascaded decoding |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded applications |
| ESD Rating (HBM) | 2000 V - exceeds JEDEC JS-001 requirements for robust handling in manufacturing |
Pinout & Package
SN74LVC138ADRG4 uses a 16-pin SOIC (D) package with 9.90 mm × 3.91 mm body size, 1.27 mm pitch, and gull-wing leads. Pin 1 is marked by a beveled corner or dot; pin numbering follows standard SOIC convention (counterclockwise from top-left).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (G2A) | Active-low enable A | Must be LOW to activate decoder; used with G2B and G1 for hierarchical enable control |
| 2 (G2B) | Active-low enable B | Second active-low enable; both G2A and G2B must be LOW for function enable |
| 3 (G1) | Active-high enable | Must be HIGH to activate decoder; complements dual active-low enables for flexible expansion |
| 4 (C) | Most significant select input | MSB of 3-bit address; determines Y4–Y7 vs Y0–Y3 group selection |
| 5 (B) | Mid-significance select input | Second bit of address; combines with A and C to uniquely select one of eight outputs |
| 6 (A) | Least significant select input | LSB of address; directly maps to Y0/Y1, Y2/Y3, Y4/Y5, Y6/Y7 pairing |
| 7 (Y7) | Active-low output 7 | Low when A=1, B=1, C=1 and all enables active; drives LED cathodes or memory chip selects |
| 8 (GND) | Ground reference | Primary return path for all internal logic and output currents; requires low-impedance PCB plane |
| 9 (Y6) | Active-low output 6 | Low when A=0, B=1, C=1; shares same timing characteristics and drive strength as Y7 |
| 10 (Y5) | Active-low output 5 | Low when A=1, B=0, C=1; identical electrical specs across all Y0–Y7 outputs |
| 11 (Y4) | Active-low output 4 | Low when A=0, B=0, C=1; supports uniform load distribution in multiplexed displays |
| 12 (Y3) | Active-low output 3 | Low when A=1, B=1, C=0; enables column scanning in 8×8 LED matrices |
| 13 (Y2) | Active-low output 2 | Low when A=0, B=1, C=0; maintains <1 ns output skew for synchronized switching |
| 14 (Y1) | Active-low output 1 | Low when A=1, B=0, C=0; compatible with TTL and CMOS input thresholds |
| 15 (Y0) | Active-low output 0 | Low when A=0, B=0, C=0; default active output during reset or initialization |
| 16 (VCC) | Power supply | Must be bypassed with 0.1 µF ceramic capacitor near pin; supports 1.65–3.6 V operation |
Key Features
| Feature | Design Value |
|---|---|
| Wide VCC range (1.65 V to 3.6 V) | Enables single-supply operation across 1.8-V microcontrollers, 2.5-V FPGAs, and 3.3-V peripherals |
| 5.5-V tolerant inputs | Eliminates external level translators when interfacing with 5-V legacy address/data buses |
| Sub-6 ns propagation delay at 3.3 V | Reduces system-level latency in memory-mapped I/O and real-time display refresh cycles |
| Three independent enable inputs | Supports daisy-chained 24-line decoding without external inverters and 32-line with one inverter |
| Output ground bounce & undershoot control | Typical VOLP < 0.8 V and VOHV > 2 V at 3.3 V - minimizes signal integrity issues in dense layouts |
| Latch-up immunity > 250 mA | Meets JESD17 requirements for robustness against transient overcurrent events |
Applications
| LED Matrix Column Driver | Memory Address Decoder |
|---|---|
|
Use Scenario: Driving 8-column cathodes in an 8×8 monochrome LED display using row-scanning technique. IC Role / Device Role / Timing Role: Low-side column switch activated per scan cycle; only one Yx output active at a time to prevent current stacking. Use Value: Enables precise column isolation with 5.8 ns delay margin, eliminating ghosting and ensuring uniform brightness across rows. |
Use Scenario: Selecting one of eight peripheral devices (e.g., ADCs, DACs, sensors) on a shared 16-bit data bus. IC Role / Device Role / Timing Role: Address decoder translating upper 3 bits of CPU address bus into individual chip-select signals. Use Value: Reduces decode logic gate count and propagation delay versus discrete NAND-based solutions, improving bus access timing. |
| Industrial I/O Expansion | Factory Automation Control |
|
Use Scenario: Expanding GPIO count of a PLC controller to manage 8 discrete solenoid valves via open-collector drivers. IC Role / Device Role / Timing Role: Demultiplexer routing a single control line to one of eight valve enable paths under microcontroller command. Use Value: Provides deterministic, glitch-free activation with ±24 mA sink capability per output, eliminating need for external buffer transistors. |
Use Scenario: Enabling sensor submodules (temperature, pressure, flow) in modular HVAC control panels based on configuration registers. IC Role / Device Role / Timing Role: Configurable module selector using G1 as firmware-controlled master enable and G2A/G2B as hardware strap inputs. Use Value: Supports field-reconfigurable hardware partitioning without PCB redesign, leveraging dual active-low enables for safety interlocks. |
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 | Wider VCC range (2 V to 6 V), slower max tpd (24 ns at 4.5 V), no 5.5-V input tolerance | Compatible with 5-V systems but lacks 1.8-V support; unsuitable for mixed-voltage designs requiring level translation | Select SN74HC138N only if operating exclusively at 5 V and timing budget allows ≥20 ns delay |
| 74LVT138PW | Higher speed (3.5 ns at 3.3 V), 3.3-V-only supply (3–3.6 V), TTL-compatible inputs, no 5.5-V tolerance | Optimized for high-speed backplane interfaces; incompatible with 1.8-V or 2.5-V logic families | Choose 74LVT138PW when maximum speed is critical and system operates strictly at 3.3 V |
Compared with SN74HC138N and 74LVT138PW, SN74LVC138ADRG4 uniquely balances ultra-low-voltage operation (1.65 V), 5.5-V input tolerance, and sub-6 ns delay-making it the only option suitable for scalable, mixed-voltage embedded systems requiring both backward compatibility and future-proof low-power design.
Availability
SN74LVC138ADRG4 is available at Aetrix Electronics and suitable for industrial I/O expansion, LED matrix driving, and memory address decoding requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for SN74LVC138ADRG4 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 connectivity technologies, with decades of leadership in logic IC innovation and industrial-grade reliability.
The SN74LVC138ADRG4 belongs to TI's LVC (Low-Voltage CMOS) logic family, engineered for interoperability across voltage domains in space-constrained, power-sensitive embedded systems such as programmable logic controllers and smart sensors.
FAQ
What is the recommended bypass capacitor for SN74LVC138ADRG4?
A 0.1-µF ceramic capacitor is recommended directly between VCC (pin 16) and GND (pin 8), placed as close as possible to the device. This minimizes power supply noise and prevents output ringing during fast transitions. For enhanced high-frequency filtering, a parallel 1-µF capacitor may be added nearby, but the 0.1-µF unit must remain adjacent to the IC pins to ensure effective decoupling of SN74LVC138ADRG4 switching transients.
Can SN74LVC138ADRG4 interface directly with a 5-V microcontroller?
Yes, SN74LVC138ADRG4 accepts input voltages up to 5.5 V while operating from a 1.65–3.6 V supply, allowing direct connection to 5-V GPIO outputs without level shifters. The inputs are TTL-compatible and internally clamped, making SN74LVC138ADRG4 ideal for bridging legacy 5-V control logic with modern low-voltage peripherals.
How does the enable logic of SN74LVC138ADRG4 support cascaded decoding?
SN74LVC138ADRG4 uses one active-high (G1) and two active-low (G2A, G2B) enables, enabling hierarchical decoding without external inverters. For example, connecting G1 of a second SN74LVC138ADRG4 to Y0 of the first allows 24-line decoding; adding one inverter on G2A extends this to 32 lines. This architecture simplifies board layout and improves timing predictability compared to NAND-based alternatives.
What is the maximum output current per Yx pin on SN74LVC138ADRG4?
Each output (Y0–Y7) of SN74LVC138ADRG4 can sink up to 24 mA at VCC = 3.0 V and source up to 24 mA at VCC = 3.0 V, with guaranteed performance across the full –40°C to +85°C temperature range. This drive strength supports direct LED column sinking or driving multiple 74LVC inputs, provided total device ICC remains within 10 µA quiescent and dynamic supply current limits.
Is SN74LVC138ADRG4 pin-compatible with older 74LS138 devices?
No, SN74LVC138ADRG4 is not pin-compatible with 74LS138 due to differing enable logic: 74LS138 uses three active-low enables (E1̅, E2̅, E3̅), whereas SN74LVC138ADRG4 uses G1 (active-high) and G2A/G2B (active-low). While both are 16-pin SOIC packages, the pin functions differ - e.g., pin 1 is G2A (not E1̅) and pin 3 is G1 (not E2̅). Direct replacement requires schematic and layout revision to match SN74LVC138ADRG4 enable mapping.
SN74LVC138ADRG4 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:
- Discontinued at Digi-Key
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 3:8
- Independent Circuits:
- 1
- Current - Output High, Low:
- 24mA, 24mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 1.65V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74LVC138ADRG4 FAQ
1.How can I place an order for SN74LVC138ADRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC138ADRG4 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 SN74LVC138ADRG4 reliable?
The price and inventory of SN74LVC138ADRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC138ADRG4 is usually 5 days.
3.What payment methods are accepted for SN74LVC138ADRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LVC138ADRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LVC138ADRG4?
SN74LVC138ADRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC138ADRG4 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 SN74LVC138ADRG4?
For technical support, including SN74LVC138ADRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC138ADRG4 requirements.
6.How does Aetrix verify that SN74LVC138ADRG4 is sourced from the original manufacturer or authorized distributors?
All SN74LVC138ADRG4 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 SN74LVC138ADRG4 meets industry standards.
7.What is the process for return or replacement of SN74LVC138ADRG4?
All SN74LVC138ADRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC138ADRG4, 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 SN74LVC138ADRG4 part is unused and in its original packaging.
Return procedure for SN74LVC138ADRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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