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Texas Instruments SN74LVC138APWT
- Part No.:
- SN74LVC138APWT
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74LVC138APWT.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,468
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Product details
Overview
SN74LVC138APWT from Texas Instruments is a 3-line to 8-line decoder/demultiplexer IC operating from 1.65 V to 3.6 V, with 5.8 ns max propagation delay at 3.3 V, inputs tolerant to 5.5 V, and active-low G2A/G2B plus active-high G1 enables. It drives LED matrix column selection in low-side configurations with precise single-output activation.
For engineers reviewing the SN74LVC138APWT datasheet, SN74LVC138APWT pinout, SN74LVC138APWT application, or SN74LVC138APWT equivalent, key selection criteria include supply voltage range (1.65–3.6 V), input overvoltage tolerance (5.5 V), propagation delay (≤5.8 ns @ 3.3 V), output drive capability (±24 mA), and TSSOP-16 package compatibility with high-density PCB layouts.
Technical Context
The SN74LVC138APWT implements combinational logic decoding using three binary select inputs (A, B, C) to activate exactly one of eight active-low outputs (Y0–Y7). All outputs remain HIGH unless all three enable conditions are met: G1 = HIGH, G2A = LOW, G2B = LOW.
Its dual-active-low + single-active-high enable architecture minimizes external logic for cascading - enabling 24-line decoding without inverters and 32-line decoding with only one inverter. Input thresholds scale with VCC (VIH = 0.65×VCC min at 1.65 V), supporting mixed-voltage system interfacing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.65 V to 3.6 V - supports modern low-voltage logic domains including 1.8 V and 2.5 V systems while maintaining full functionality. |
| Max Propagation Delay | 5.8 ns at VCC = 3.3 V - enables use in high-speed memory decoding and real-time LED scanning where timing margins are tight. |
| Input Voltage Tolerance | Up to 5.5 V - allows direct interface with legacy 5-V controllers without level-shifting circuitry. |
| Output Drive Strength | ±24 mA at VCC = 3.0 V - sufficient to directly sink LED column current in multiplexed displays without external drivers. |
| Logic Family | LVC (Low-Voltage CMOS) - ensures rail-to-rail output swing, low static current (10 µA max ICC), and ESD robustness (2000 V HBM). |
| Operating Temperature | –40°C to +85°C - qualified for industrial and commercial embedded applications including building automation and factory control. |
Pinout & Package
TSSOP-16 package (4.4 mm × 5.0 mm body, 0.65 mm pitch), thermally enhanced for surface-mount assembly in space-constrained designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (G2A) | Active-low enable A | Must be LOW to enable decoding; used with G2B and G1 to gate entire output array. |
| 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 enable decoding; complements dual active-low enables for flexible hierarchical control. |
| 4 (C) | Select input C (MSB) | Most significant bit of 3-bit address; determines higher-order output group (Y4–Y7 vs Y0–Y3). |
| 5 (B) | Select input B | Mid-significance bit; combined with A and C to uniquely select one of eight outputs. |
| 6 (A) | Select input A (LSB) | Least significant bit; final bit resolving output identity within selected group. |
| 7 (Y7) | Active-low output 7 | Only asserted when A=1, B=1, C=1 and all enables active; sinks current when enabled. |
| 8 (GND) | Ground reference | Primary return path for all internal logic and output currents; requires low-impedance PCB connection. |
| 9 (Y6) | Active-low output 6 | Asserted for A=0, B=1, C=1; identical electrical behavior to Y7 but mapped to different decode state. |
| 10 (Y5) | Active-low output 5 | Asserted for A=1, B=0, C=1; maintains consistent VOL/VOLH specs across all outputs. |
| 11 (Y4) | Active-low output 4 | Asserted for A=0, B=0, C=1; shares same timing and drive characteristics as other Yx outputs. |
| 12 (Y3) | Active-low output 3 | Asserted for A=1, B=1, C=0; supports simultaneous enable/disable of multiple outputs via G1/G2 controls. |
| 13 (Y2) | Active-low output 2 | Asserted for A=0, B=1, C=0; designed for uniform skew (tsk(o) ≤1 ns) across all outputs. |
| 14 (Y1) | Active-low output 1 | Asserted for A=1, B=0, C=0; matches Y0/Y2/Y3 in propagation delay and load drive capability. |
| 15 (Y0) | Active-low output 0 (LSB) | Asserted for A=0, B=0, C=0; lowest-numbered output, commonly used as default or reset channel. |
| 16 (VCC) | Supply voltage | Power rail for internal logic and output buffers; requires local 0.1-µF bypass capacitor per TI layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Wide supply range | 1.65 V to 3.6 V operation enables drop-in replacement in 1.8-V, 2.5-V, and 3.3-V systems without redesign. |
| 5.5-V-tolerant inputs | Eliminates need for external level shifters when interfacing with 5-V microcontrollers or FPGAs. |
| Sub-6-ns propagation delay | Meets timing-critical requirements in high-speed memory decoding and real-time display multiplexing. |
| Three independent enables | G1 (active-high), G2A/G2B (active-low) allow hierarchical expansion to 24- or 32-line decoders with zero or one inverter. |
| Low dynamic power | 27 pF typical power dissipation capacitance at 3.3 V/10 MHz reduces switching noise and thermal load. |
Applications
| LED Matrix Column Driver | Memory Address Decoder |
|---|---|
|
Use Scenario: Driving 8-column LED matrix in multiplexed scan mode with microcontroller GPIOs. IC Role / Device Role / Timing Role: Low-side column selector that asserts exactly one Yx output per cycle to sink current from illuminated column. Use Value: Ensures no column contention; leverages 24-mA sink capability to eliminate external transistors while maintaining <5.8 ns address setup time. |
Use Scenario: Translating 3-bit address bus into chip-select signals for eight peripheral devices. IC Role / Device Role / Timing Role: Combinational address decoder generating active-low CS lines synchronized to memory access cycles. Use Value: Reduces system decode latency to ≤5.8 ns at 3.3 V, ensuring negligible impact on overall memory access time. |
| Industrial I/O Expansion | Factory Automation Logic Controller |
|
Use Scenario: Expanding microcontroller GPIO count to control eight discrete actuators or sensors. IC Role / Device Role / Timing Role: Digital demultiplexer routing a single data line to one of eight output channels under address control. Use Value: Enables compact, low-cost I/O expansion using only three address lines and two enable signals - no additional glue logic required. |
Use Scenario: Implementing programmable logic functions in PLC modules with fixed 3-bit instruction encoding. IC Role / Device Role / Timing Role: Fixed-function decoder interpreting opcode bits to activate corresponding control outputs in deterministic sequence. Use Value: Guarantees sub-6-ns decision latency and latch-up immunity (>250 mA per JESD17), critical for safety-critical motion control loops. |
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 | Higher VCC range (2 V–6 V), slower tpd (21 ns @ 4.5 V), no 5.5-V input tolerance. | Suitable for legacy 5-V systems but incompatible with 1.8-V logic; lacks mixed-voltage interface capability. | Choose SN74HC138N only if operating exclusively at 5 V and timing slack >15 ns is acceptable. |
| 74LVC138AD | Same logic function and specs, but in SOIC-16 (9.9 mm × 3.91 mm) instead of TSSOP-16 (5.0 mm × 4.4 mm). | Requires larger PCB area; less suitable for high-density portable or industrial modules. | Choose 74LVC138AD only when SOIC footprint is mandated by existing board layout or reflow process constraints. |
Compared with SN74HC138N, SN74LVC138APWT delivers 3.6× faster propagation and 5.5-V input tolerance for mixed-voltage designs; compared with 74LVC138AD, it saves >50% board area while retaining identical electrical performance and thermal characteristics.
Availability
SN74LVC138APWT is available at Aetrix Electronics and suitable for LED matrix displays, industrial I/O expansion, memory address decoding, and factory automation logic controllers requiring stable component supply and long-term manufacturability.
Supply support for SN74LVC138APWT 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 company specializing in analog and embedded processing solutions, with leadership in logic, power management, and signal chain technologies.
The SN74LVC138APWT belongs to TI's LVC logic family, engineered for low-voltage, high-speed digital interfacing in space- and power-constrained industrial and commercial systems.
FAQ
What is the maximum operating frequency supported by SN74LVC138APWT?
The SN74LVC138APWT does not specify a maximum clock frequency because it is a combinational logic device without an internal clock. Its usable switching rate is determined by propagation delay (≤5.8 ns at 3.3 V) and system-level timing margins. In practice, SN74LVC138APWT reliably supports address/data strobe rates up to ~100 MHz in well-designed PCB layouts with controlled impedance and proper decoupling.
Can SN74LVC138APWT interface directly with a 5-V microcontroller?
Yes, SN74LVC138APWT accepts input voltages up to 5.5 V regardless of VCC level, allowing direct connection to 5-V GPIOs without level shifters. Its outputs swing rail-to-rail (0 V to VCC), so interfacing with 5-V logic requires external pull-up resistors or a compatible receiver - but input-side compatibility is fully guaranteed per TI's absolute maximum ratings and recommended operating conditions.
Does SN74LVC138APWT require external pull-up resistors on its Yx outputs?
No, SN74LVC138APWT features push-pull CMOS outputs capable of actively driving HIGH (to VCC) and LOW (to GND). External pull-ups are unnecessary unless open-drain behavior is specifically required - which SN74LVC138APWT does not provide. The outputs are designed for direct connection to LEDs (cathode-side), logic inputs, or other CMOS loads.
How does the enable structure of SN74LVC138APWT support cascaded decoding?
SN74LVC138APWT uses three enables - G1 (active-high), G2A and G2B (both active-low) - enabling hierarchical expansion. For example, two SN74LVC138APWT devices can decode 24 lines by connecting G1 of each to separate higher-order address bits while sharing A/B/C and tying G2A/G2B to common enables. This eliminates external inverters needed with single-enable decoders like SN74HC138.
Is SN74LVC138APWT suitable for automotive applications?
SN74LVC138APWT is rated for –40°C to +85°C operation and meets JESD17 latch-up immunity (>250 mA), but it is not AEC-Q100 qualified. It is appropriate for under-hood industrial equipment and commercial vehicle subsystems, but not for safety-critical automotive ECUs requiring formal qualification. For automotive-grade alternatives, consult TI's AEC-Q100-certified logic portfolio.
SN74LVC138APWT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 16-TSSOP (0.173", 4.40mm 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:
- 1.65V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
SN74LVC138APWT FAQ
1.How can I place an order for SN74LVC138APWT through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC138APWT 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 SN74LVC138APWT reliable?
The price and inventory of SN74LVC138APWT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC138APWT is usually 5 days.
3.What payment methods are accepted for SN74LVC138APWT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LVC138APWT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LVC138APWT?
SN74LVC138APWT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC138APWT 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 SN74LVC138APWT?
For technical support, including SN74LVC138APWT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC138APWT requirements.
6.How does Aetrix verify that SN74LVC138APWT is sourced from the original manufacturer or authorized distributors?
All SN74LVC138APWT 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 SN74LVC138APWT meets industry standards.
7.What is the process for return or replacement of SN74LVC138APWT?
All SN74LVC138APWT units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC138APWT, 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 SN74LVC138APWT part is unused and in its original packaging.
Return procedure for SN74LVC138APWT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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