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Texas Instruments SN74LVC138APWE4
- Part No.:
- SN74LVC138APWE4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74LVC138APWE4.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,650
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Product details
Overview
SN74LVC138APWE4 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 SN74LVC138APWE4 datasheet, SN74LVC138APWE4 pinout, SN74LVC138APWE4 application, or SN74LVC138APWE4 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), enable logic configuration (two active-low, one active-high), and TSSOP-16 package compatibility with high-density PCB layouts.
Technical Context
The SN74LVC138APWE4 implements binary decoding of three select inputs (A, B, C) to assert exactly one of eight active-low outputs (Y0–Y7), conditioned on simultaneous assertion of G1 (high) and deassertion of both G2A and G2B (low). Its CMOS design ensures balanced drive strength and rail-to-rail output swing within VCC.
Enable inputs support hierarchical expansion: two active-low enables (G2A, G2B) and one active-high enable (G1) allow cascading without external inverters-e.g., a 24-line decoder requires no additional logic, while a 32-line implementation needs only one inverter. The device functions as both decoder and demultiplexer, with any enable pin usable as data input in demux mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.65 V to 3.6 V - supports dual-voltage system interfacing and low-power operation down to 1.65 V logic rails. |
| Max Propagation Delay | 5.8 ns at VCC = 3.3 V - enables use in high-speed memory decoding and real-time LED scanning with minimal system latency. |
| Input Voltage Tolerance | Up to 5.5 V - allows direct connection to 5-V legacy controllers without level-shifting circuitry. |
| Output Drive Strength | ±24 mA at VCC = 3.0 V - sufficient for driving LED columns or TTL-compatible loads without external buffers. |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded applications including factory automation and building control systems. |
| ESD Rating (HBM) | 2000 V - meets JEDEC JS-001 standard, ensuring robustness during board assembly and handling. |
Pinout & Package
TSSOP-16 package (4.4 mm × 5.0 mm body, 0.65 mm pitch), lead-free (NiPdAu), moisture sensitivity level 1 (260°C reflow unlimited).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (G2A) | Active-low enable A | Must be LOW to enable decoding; used for hierarchical enable chaining in multi-device systems. |
| 2 (G2B) | Active-low enable B | Second active-low enable; both G2A and G2B must be LOW alongside G1 HIGH for output activation. |
| 3 (G1) | Active-high enable | Primary enable signal; HIGH enables function, allowing flexible control via microcontroller GPIO or system bus. |
| 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 | Middle bit of address; combined with A and C, fully defines which of eight outputs is asserted. |
| 6 (A) | Select input A (LSB) | Least significant bit; completes 3-bit binary selection for precise Y0–Y7 mapping. |
| 7 (Y7) | Active-low output 7 | Asserted LOW when A=1, B=1, C=1 and all enables active; used for highest-addressed peripheral or LED column. |
| 8 (GND) | Ground reference | Return path for all internal logic and output currents; requires low-impedance PCB plane connection. |
| 9 (Y6) | Active-low output 6 | Asserted LOW for A=0, B=1, C=1; supports discrete peripheral enable or segmented display control. |
| 10 (Y5) | Active-low output 5 | Asserted LOW for A=1, B=0, C=1; provides dedicated channel for sensor interface or I/O expansion. |
| 11 (Y4) | Active-low output 4 | Asserted LOW for A=0, B=0, C=1; enables selective activation of subsystems in modular hardware designs. |
| 12 (Y3) | Active-low output 3 | Asserted LOW for A=1, B=1, C=0; commonly used in memory bank selection or multiplexed bus routing. |
| 13 (Y2) | Active-low output 2 | Asserted LOW for A=0, B=1, C=0; supports timing-critical control signals in real-time embedded systems. |
| 14 (Y1) | Active-low output 1 | Asserted LOW for A=1, B=0, C=0; delivers deterministic low-side drive for status indicators or relay drivers. |
| 15 (Y0) | Active-low output 0 | Asserted LOW for A=0, B=0, C=0; default channel for boot-time initialization or primary peripheral enable. |
| 16 (VCC) | Supply voltage | Power rail for core logic and output drivers; requires local 0.1 µF ceramic bypass capacitor per TI layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Wide supply range (1.65–3.6 V) | Enables interoperability across mixed-voltage systems (e.g., 1.8-V MCU controlling 3.3-V peripherals) without level shifters. |
| 5.5-V tolerant inputs | Permits direct interface with 5-V microcontrollers, FPGAs, or legacy logic, reducing BOM count and layout complexity. |
| Sub-6-ns propagation delay @ 3.3 V | Minimizes decoding latency in high-speed memory subsystems and real-time LED refresh cycles (e.g., >1 kHz frame rates). |
| Three independent enable inputs | Supports scalable system architecture: G1 for global enable, G2A/G2B for sub-system gating-enabling 24-line decoding without inverters. |
| Active-low outputs with strong sink capability | Delivers up to 24 mA per output at 3.0 V, suitable for direct LED column driving or TTL load termination without external transistors. |
Applications
| LED Matrix Column Driver | Memory Address Decoder |
|---|---|
|
Use Scenario: Driving the cathode side of an 8×8 monochrome LED display using row-scanning and column-select logic. IC Role / Device Role / Timing Role: Acts as low-side column selector; each Yx output sinks current for one column while rows are sequentially activated. Use Value: Ensures only one column is active per scan cycle, eliminating ghosting and enabling uniform brightness control via PWM on row lines. |
Use Scenario: Translating 3-bit address lines into individual chip-select signals for eight SRAM or flash memory banks. IC Role / Device Role / Timing Role: Provides fast, deterministic address decoding with minimal added latency to memory access paths. Use Value: Reduces effective system decode delay to ≤5.8 ns, keeping total access time below typical 10-ns SRAM tAA specifications. |
| Industrial I/O Expansion | Factory Automation Control Logic |
|
Use Scenario: Enabling/disabling up to eight discrete sensors or actuators (e.g., limit switches, solenoids) from a microcontroller's limited GPIO set. IC Role / Device Role / Timing Role: Functions as programmable output expander; G1 controlled by MCU, A/B/C set via register writes or hardwired straps. Use Value: Eliminates need for discrete MOSFETs or buffer ICs-each Yx output directly drives 24-mA loads at industrial supply voltages. |
Use Scenario: Controlling eight pneumatic valves in a PLC-based packaging machine, where precise sequencing and fault isolation are critical. IC Role / Device Role / Timing Role: Serves as safety-gated decoder: G2A tied to emergency stop signal, G2B to watchdog timeout, G1 to main controller. Use Value: Forces all outputs HIGH (safe state) if any enable fails, meeting SIL-2 functional safety requirements without external supervision logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-to-8 decoder/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC138N | Wider VCC range (2–6 V), slower speed (21 ns @ 4.5 V), no 5.5-V input tolerance | Compatible with 5-V-only systems but unsuitable for 1.8-V or mixed-voltage interfaces | Choose for cost-sensitive 5-V legacy designs where speed <10 ns is not required. |
| 74LVC138PW | Identical electrical specs and pinout; differs only in RoHS compliance marking and tape-and-reel packaging | No functional difference; full drop-in replacement in both schematic and layout | Prefer for new designs requiring full TI-compliant RoHS documentation and traceable sourcing. |
Compared with SN74HC138N, SN74LVC138APWE4 enables lower-voltage operation and faster timing; compared with 74LVC138PW, it shares identical functionality but carries TI's E4 suffix denoting enhanced quality screening and extended temperature validation.
Availability
SN74LVC138APWE4 is available at Aetrix Electronics and suitable for industrial control panels, LED display modules, and memory subsystems requiring stable component supply, long-term lifecycle assurance, and TI-qualified automotive/industrial grade reliability.
Supply support for SN74LVC138APWE4 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 high-reliability logic and interface solutions.
The SN74LVC138APWE4 belongs to TI's LVC (Low-Voltage CMOS) logic family, engineered for low-power, high-speed operation in portable, industrial, and communications equipment where voltage scalability and noise immunity are critical.
FAQ
What is the maximum operating frequency supported by the SN74LVC138APWE4?
The SN74LVC138APWE4 does not specify a maximum clock frequency because it is a combinational logic device-not clocked. Its performance is defined by propagation delay: 5.8 ns maximum at 3.3 V, supporting input transition rates up to ~170 MHz (1/5.8 ns) in practice. System-level timing depends on setup/hold margins of upstream drivers and load capacitance, per TI's recommended 10 ns/V input slew rate limit.
Can the SN74LVC138APWE4 be used with a 5-V microcontroller?
Yes, the SN74LVC138APWE4 accepts input voltages up to 5.5 V regardless of VCC level, making it safe to interface directly with 5-V microcontrollers even when powered from 1.8 V or 3.3 V. No level-shifting circuitry is needed-inputs are overvoltage-tolerant, and outputs remain compatible with 5-V logic thresholds when VCC ≥ 2.7 V (VOH ≥ 2.0 V).
How does the enable logic work on the SN74LVC138APWE4?
The SN74LVC138APWE4 requires all three enables to be simultaneously active: G1 must be HIGH, and both G2A and G2B must be LOW. If any enable is inactive, all eight outputs (Y0–Y7) go HIGH (inactive state). This three-input enable scheme allows flexible hierarchical control-e.g., G1 for system-level enable, G2A for subsystem lockout, G2B for maintenance mode.
Is the SN74LVC138APWE4 suitable for driving LEDs directly?
Yes, the SN74LVC138APWE4 can drive LEDs directly in low-side configuration: each Yx output sinks up to 24 mA at VCC = 3.0 V, sufficient for standard 20-mA indicator LEDs. For higher-current LEDs or multiplexed displays, verify voltage drop across series resistor and thermal limits-TI specifies 100 mA total continuous current through VCC/GND pins.
What package type is used for the SN74LVC138APWE4?
The SN74LVC138APWE4 uses a TSSOP-16 (PW) package: 5.0 mm × 4.4 mm body size, 0.65 mm lead pitch, surface-mount, lead-free (NiPdAu finish), and moisture sensitivity level 1 (unlimited floor life at ≤30°C/60% RH). It is pin-compatible with other TSSOP-16 logic devices and optimized for automated assembly.
SN74LVC138APWE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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
SN74LVC138APWE4 FAQ
1.How can I place an order for SN74LVC138APWE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC138APWE4 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 SN74LVC138APWE4 reliable?
The price and inventory of SN74LVC138APWE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC138APWE4 is usually 5 days.
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SN74LVC138APWE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC138APWE4 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 SN74LVC138APWE4?
For technical support, including SN74LVC138APWE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC138APWE4 requirements.
6.How does Aetrix verify that SN74LVC138APWE4 is sourced from the original manufacturer or authorized distributors?
All SN74LVC138APWE4 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 SN74LVC138APWE4 meets industry standards.
7.What is the process for return or replacement of SN74LVC138APWE4?
All SN74LVC138APWE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC138APWE4, 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 SN74LVC138APWE4 part is unused and in its original packaging.
Return procedure for SN74LVC138APWE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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