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Texas Instruments SN74LVC138APWG4
- Part No.:
- SN74LVC138APWG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74LVC138APWG4.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,216
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Product details
Overview
SN74LVC138APWG4 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, propagation delay as low as 5.8 ns at 3.3 V, and active-low G2A/G2B plus active-high G1 enables for flexible hierarchical decoding. It serves as a column selector in LED matrix displays and memory address decoder in industrial microcontroller systems.
For engineers reviewing the SN74LVC138APWG4 datasheet, SN74LVC138APWG4 pinout, SN74LVC138APWG4 application, or SN74LVC138APWG4 equivalent, key selection criteria include supply voltage range (1.65–3.6 V), input overvoltage tolerance (5.5 V), propagation delay (≤6.7 ns at 3.3 V), enable logic configuration (2× active-low + 1× active-high), and SOIC-16 package compatibility with standard PCB footprints.
Technical Context
The SN74LVC138APWG4 implements a binary-select decoder architecture where inputs A (LSB), B, and C (MSB) determine which of eight outputs (Y0–Y7) is driven LOW; all others remain HIGH. Its three enable inputs-G1 (active-high), G2A and G2B (both active-low)-allow cascading without external inverters, enabling 24-line decoding natively and 32-line with one external inverter.
Designed for mixed-voltage systems, it accepts 5-V TTL-level inputs while powered from 1.65–3.6 V, supporting level translation between legacy and modern logic families. Output drive capability is ±24 mA at 3.0 V, with ground bounce (VOLP) < 0.8 V and output undershoot (VOHV) > 2 V under typical conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 1.65 V to 3.6 V - Enables direct interface with 1.8-V, 2.5-V, and 3.3-V logic domains without level shifters. |
| Input Voltage Range | Up to 5.5 V - Allows connection to 5-V microcontrollers or legacy peripherals without clamping diodes or external protection. |
| Max Propagation Delay | 5.8 ns at VCC = 3.3 V - Supports high-speed address decoding in sub-100-MHz digital systems with negligible timing overhead. |
| Output Drive | ±24 mA at VCC = 3.0 V - Sufficient to directly sink LED columns or drive CMOS/TTL fan-out loads without buffers. |
| Enable Logic | G1 (active-high), G2A & G2B (active-low) - Permits hierarchical expansion using standard logic gates; no external inversion needed for 24-line decode. |
| Operating Temperature | –40°C to +85°C - Qualified for industrial-grade embedded applications including factory automation and power infrastructure. |
Pinout & Package
SN74LVC138APWG4 uses a 16-pin SOIC (Small Outline Integrated Circuit) package with 1.27-mm pitch, 9.90 mm × 3.91 mm body size, and RoHS-compliant NiPdAu lead finish. 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 to gate entire output bank. |
| 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 G2A/G2B for flexible enable logic. |
| 4 (C) | Select input C (MSB) | Most significant bit of 3-bit address; determines upper/lower half of Y0–Y7 outputs. |
| 5 (B) | Select input B | Middle bit of address; combined with A and C to uniquely select one of eight outputs. |
| 6 (A) | Select input A (LSB) | Least significant bit; final bit resolving exact output line (e.g., A=0,B=0,C=0 → Y0). |
| 7 (Y7) | Output 7 (active-low) | Complementary output driven LOW when A=1,B=1,C=1; all other outputs HIGH during selection. |
| 8 (GND) | Ground reference | Primary return path for all internal logic and output currents; requires low-impedance PCB plane. |
| 9 (Y6) | Output 6 (active-low) | Driven LOW only when A=0,B=1,C=1; supports discrete column/row addressing in multiplexed displays. |
| 10 (Y5) | Output 5 (active-low) | Used in memory chip select trees where each output enables one SRAM or Flash device. |
| 11 (Y4) | Output 4 (active-low) | Enables peripheral interfaces (e.g., UART, SPI devices) via decoded address space mapping. |
| 12 (Y3) | Output 3 (active-low) | Supports dynamic bus gating in FPGA/CPLD I/O expansion subsystems. |
| 13 (Y2) | Output 2 (active-low) | Drives low-side switches in LED backlighting arrays requiring precise current control per segment. |
| 14 (Y1) | Output 1 (active-low) | Interfaces with optocoupler inputs for isolated control signal distribution in industrial PLCs. |
| 15 (Y0) | Output 0 (active-low, LSB) | First output activated (A=B=C=0); commonly used for boot device selection in embedded bootloaders. |
| 16 (VCC) | Supply voltage | Power rail for core logic and output drivers; requires local 0.1-µF ceramic bypass capacitor placed ≤2 mm from pin. |
Key Features
| Feature | Design Value |
|---|---|
| Wide VCC range (1.65–3.6 V) | Supports single-supply operation across 1.8-V, 2.5-V, and 3.3-V system rails without voltage translators. |
| 5.5-V tolerant inputs | Eliminates need for external level-shifting circuitry when interfacing with 5-V microcontrollers or sensors. |
| Sub-6-ns propagation delay | Reduces address decode latency in high-speed memory subsystems, improving effective system throughput. |
| Three independent enable inputs | Enables scalable decoding architectures: 24-line without inverters, 32-line with one inverter, minimizing gate count. |
| Low ground bounce (VOLP < 0.8 V) | Maintains signal integrity during fast switching, reducing EMI and preventing false triggering in adjacent circuits. |
Applications
| LED Matrix Column Driver | Memory Address Decoder |
|---|---|
|
Use Scenario: Driving 8-column common-anode LED matrix in industrial HMI panels with microcontroller GPIO constraints. IC Role / Device Role / Timing Role: Low-side column selector that sequentially activates one column at a time while row drivers source current. Use Value: Ensures only one column is active per cycle, preventing ghosting and enabling uniform brightness control via PWM on row lines. |
Use Scenario: Selecting among eight SRAM chips in a 64-kB memory expansion for an ARM Cortex-M7-based motor controller. IC Role / Device Role / Timing Role: Address-space partitioner translating upper address bits into individual chip-enable signals. Use Value: Reduces MCU address bus loading and eliminates timing-critical discrete NAND gate trees for chip selection. |
| Industrial I/O Expansion | Factory Automation Bus Gating |
|
Use Scenario: Enabling/disabling up to eight isolated analog input channels in a programmable logic controller (PLC) analog module. IC Role / Device Role / Timing Role: Digital switch controller routing enable signals to precision ADC front-ends based on configuration register value. Use Value: Provides deterministic channel activation with <6.7 ns setup margin, meeting IEC 61000-4-4 surge immunity timing requirements. |
Use Scenario: Controlling data flow between two CAN FD nodes and an Ethernet gateway in a smart sensor network node. IC Role / Device Role / Timing Role: Bus arbitration enabler that gates transceiver standby modes based on real-time traffic priority flags. Use Value: Low-latency enable/disable (<7 ns) ensures sub-microsecond response to bus contention events without protocol violation. |
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 (2–6 V), slower max tpd (21 ns at 4.5 V), no 5.5-V input tolerance. | Suitable for legacy 5-V-only systems; not recommended for mixed-voltage or high-speed designs. | Choose SN74HC138N only if operating exclusively at 5 V and timing budget allows ≥20-ns delay. |
| 74LVC138PW | Identical electrical specs but TSSOP-16 package (5.00 mm × 4.40 mm); same pinout as SOIC but smaller footprint. | Better suited for space-constrained PCBs; thermal resistance RθJA = 108.9°C/W vs 86.8°C/W for SOIC. | Select 74LVC138PW when board area is critical and thermal management accommodates higher junction rise. |
Compared with SN74HC138N and 74LVC138PW, SN74LVC138APWG4 delivers optimal balance of speed (5.8 ns), voltage flexibility (1.65–3.6 V), and 5.5-V input tolerance in a standard SOIC-16 package-making it ideal for new industrial designs requiring interoperability across voltage domains.
Availability
SN74LVC138APWG4 is available at Aetrix Electronics and suitable for LED matrix displays, memory address decoding, and industrial I/O expansion requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for SN74LVC138APWG4 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 experience in logic IC design and industrial-grade qualification.
The SN74LVC138A product line was engineered for high-performance memory decoding and data routing in industrial, automotive, and communications systems-prioritizing low propagation delay, wide supply range, and robust enable logic for scalable system integration.
FAQ
What is the maximum propagation delay of SN74LVC138APWG4 at 3.3 V?
The maximum propagation delay of SN74LVC138APWG4 is 6.7 ns when measured from any select input (A, B, or C) to any output (Y0–Y7) at VCC = 3.3 V ± 0.3 V and TA = 25°C. This value is confirmed in Section 6.7 of the official TI datasheet SCAS291W. The SN74LVC138APWG4 achieves this performance while maintaining full functionality across its rated temperature range (–40°C to +85°C).
Can SN74LVC138APWG4 accept 5-V input signals while powered from 1.8 V?
Yes, SN74LVC138APWG4 supports input voltages up to 5.5 V regardless of VCC level, including when powered from 1.8 V. This 5.5-V input tolerance is explicitly specified in Section 6.1 (Absolute Maximum Ratings) and Section 6.3 (Recommended Operating Conditions) of the TI datasheet. The SN74LVC138APWG4 uses overvoltage-tolerant input structures that prevent damage and ensure correct logic interpretation without external clamping components.
What package type does SN74LVC138APWG4 use, and is it RoHS-compliant?
SN74LVC138APWG4 uses a 16-pin SOIC (D) package with dimensions 9.90 mm × 3.91 mm and 1.27-mm lead pitch. It is RoHS-compliant with NiPdAu lead finish and meets Level-1 moisture sensitivity (MSL-1) per J-STD-020. This information is verified in TI's Packaging and Orderable Information addendum, where SN74LVC138APWG4 is listed as active with "Yes" under RoHS and "NIPDAU" under lead finish.
How do the enable inputs G1, G2A, and G2B interact in SN74LVC138APWG4?
In SN74LVC138APWG4, all three enable inputs must be simultaneously asserted for any output to activate: G1 must be HIGH, and both G2A and G2B must be LOW. If any enable is inactive, all outputs (Y0–Y7) go HIGH. This triple-enable structure allows hierarchical decoding-e.g., using G1 as a system-level enable and G2A/G2B for subsystem selection-without external logic gates, as documented in Section 8.3.1 and Table 2 of the datasheet.
Is SN74LVC138APWG4 suitable for driving LEDs directly?
Yes, SN74LVC138APWG4 can directly drive LEDs as a low-side switch: each output (Y0–Y7) sinks up to 24 mA at VCC = 3.0 V (Section 6.3), sufficient for indicator LEDs or column drivers in multiplexed displays. However, current-limiting resistors must be placed in series with each LED anode, and total device supply current must remain within ICC limits (10 µA quiescent, plus dynamic load). This capability is validated in TI's Application Report SCLA015.
SN74LVC138APWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- 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-TSSOP
SN74LVC138APWG4 FAQ
1.How can I place an order for SN74LVC138APWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC138APWG4 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 SN74LVC138APWG4 reliable?
The price and inventory of SN74LVC138APWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC138APWG4 is usually 5 days.
3.What payment methods are accepted for SN74LVC138APWG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LVC138APWG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LVC138APWG4?
SN74LVC138APWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC138APWG4 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 SN74LVC138APWG4?
For technical support, including SN74LVC138APWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC138APWG4 requirements.
6.How does Aetrix verify that SN74LVC138APWG4 is sourced from the original manufacturer or authorized distributors?
All SN74LVC138APWG4 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 SN74LVC138APWG4 meets industry standards.
7.What is the process for return or replacement of SN74LVC138APWG4?
All SN74LVC138APWG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC138APWG4, 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 SN74LVC138APWG4 part is unused and in its original packaging.
Return procedure for SN74LVC138APWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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