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Texas Instruments SN74LVC138ANSRG4
- Part No.:
- SN74LVC138ANSRG4
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74LVC138ANSRG4.pdf
- Description:
- IC DECODER/DEMUX 1 X 3:8 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,449
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Product details
Overview
SN74LVC138ANSRG4 from Texas Instruments is a 3-line to 8-line decoder/demultiplexer IC operating from 1.65 V to 3.6 V, featuring active-low G2A/G2B and active-high G1 enables, 5.8 ns max propagation delay at 3.3 V, and 5.5 V-tolerant inputs. It drives LED matrix column selection in low-side configurations with precise one-of-eight output activation.
For engineers reviewing the SN74LVC138ANSRG4 datasheet, SN74LVC138ANSRG4 pinout, SN74LVC138ANSRG4 application, or SN74LVC138ANSRG4 equivalent, key selection criteria include enable logic polarity compatibility, 16-pin SOP (NS) package footprint, 3.3 V/1.8 V mixed-voltage system interfacing, and demultiplexing latency under 6.7 ns at 3.3 V.
Technical Context
The SN74LVC138ANSRG4 implements combinational decoding logic where binary inputs A (LSB), B, and C (MSB) select exactly one of eight active-low outputs (Y0–Y7) when all three enables-G1 (high-active), G2A and G2B (both low-active)-are simultaneously asserted. No internal latching or clocking is present; operation is purely level-sensitive.
Its CMOS design supports voltage translation: inputs accept up to 5.5 V regardless of VCC (1.65–3.6 V), enabling direct interface with legacy 5 V logic while driving 3.3 V or 1.8 V loads. Output drive strength is ±24 mA at 3.0 V, with rail-to-rail VOL/VOH specified across the full supply range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.65 V to 3.6 V - Enables direct integration into 1.8 V and 3.3 V systems without level shifters. |
| Input Voltage Tolerance | Up to 5.5 V - Allows safe connection to 5 V microcontrollers or FPGAs without external clamping. |
| Max Propagation Delay | 5.8 ns at VCC = 3.3 V - Ensures sub-6 ns address decoding critical for high-speed memory and display timing. |
| Output Drive Current | ±24 mA at VCC = 3.0 V - Sufficient to directly sink LED columns or drive multiple LVC inputs without buffers. |
| Enable Logic | G1 high-active, G2A/G2B low-active - Reduces external gate count when cascading decoders or implementing hierarchical enable trees. |
| Operating Temperature | –40°C to +85°C - Qualified for industrial-grade embedded control and automation applications. |
Pinout & Package
SN74LVC138ANSRG4 uses a 16-pin SOP (NS) package measuring 9.90 mm × 3.91 mm, with standard 1.27 mm pitch and gull-wing leads. Pin 1 is marked by a beveled corner or dot; pin numbering follows counter-clockwise convention from top-left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (G2A) | Active-low enable A | Must be LOW to enable decoding; tied HIGH disables all outputs (Y0–Y7 = HIGH). |
| 2 (G2B) | Active-low enable B | Second low-active enable; both G2A and G2B must be LOW for function, providing dual-safety enable path. |
| 3 (G1) | Active-high enable | Must be HIGH to enable decoding; complements G2A/G2B for flexible hierarchical enable schemes. |
| 4 (C) | Select input C (MSB) | Most significant bit of 3-bit address; determines upper/lower half of Y0–Y7 output group. |
| 5 (B) | Select input B | Middle bit of address; partitions selected quadrant within enabled half. |
| 6 (A) | Select input A (LSB) | Least significant bit; fully resolves which single output (Y0–Y7) goes LOW. |
| 7 (Y7) | Output 7 (active-low) | Asserted (LOW) only when A=B=C=1 and all enables active; highest-numbered decoded output. |
| 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) | Asserted when A=0, B=1, C=1; used for fixed-function peripheral addressing or segment selection. |
| 10 (Y5) | Output 5 (active-low) | Asserted when A=1, B=0, C=1; supports discrete I/O expansion in microcontroller systems. |
| 11 (Y4) | Output 4 (active-low) | Asserted when A=0, B=0, C=1; commonly assigned to non-critical peripherals to minimize routing congestion. |
| 12 (Y3) | Output 3 (active-low) | Asserted when A=1, B=1, C=0; suitable for interrupt line selection or status flag generation. |
| 13 (Y2) | Output 2 (active-low) | Asserted when A=0, B=1, C=0; provides deterministic low-side drive for multiplexed sensors. |
| 14 (Y1) | Output 1 (active-low) | Asserted when A=1, B=0, C=0; used in address decoding for SRAM or flash memory blocks. |
| 15 (Y0) | Output 0 (active-low, LSB) | Asserted only when A=B=C=0; default selection for boot devices or primary peripheral interfaces. |
| 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 |
|---|---|
| 3-to-8 decoding with three enable inputs | Enables scalable address decoding up to 32 lines using only one external inverter, reducing board space and BOM count. |
| 5.5 V tolerant inputs at any VCC ≥1.65 V | Eliminates need for external level translators when interfacing with 5 V controllers in mixed-voltage systems. |
| Sub-6 ns propagation delay at 3.3 V | Meets tight timing budgets in high-speed memory subsystems and real-time display refresh circuits. |
| Rail-to-rail output swing with ±24 mA drive | Directly drives LEDs, MOSFET gates, or multiple LVC inputs without intermediate buffers or current-limiting resistors. |
| Latch-up immunity >250 mA | Ensures robustness against transient overcurrent events in industrial environments with noisy power rails. |
Applications
| LED Matrix Column Driver | Memory Address Decoder |
|---|---|
|
Use Scenario: Driving the cathode side of an 8×8 monochrome LED display where rows are scanned via microcontroller GPIO and columns are selected sequentially. IC Role / Device Role / Timing Role: Low-side column selector that asserts exactly one Yx output LOW per cycle, synchronizing with row activation to illuminate single pixels. Use Value: Prevents ghosting by guaranteeing only one column is active at a time; 5.8 ns delay ensures precise alignment with microcontroller timing margins. |
Use Scenario: Decoding 3-bit address lines from an FPGA to select among eight peripheral registers or memory-mapped I/O blocks. IC Role / Device Role / Timing Role: Combinational address decoder translating A[2:0] into individual chip-select signals (CS0–CS7) for parallel bus peripherals. Use Value: Eliminates FPGA logic resource usage for simple decoding; 1.65 V operation allows direct connection to low-power FPGA I/O banks. |
| Industrial I/O Expansion | Factory Automation Bus Selector |
|
Use Scenario: Expanding a PLC controller's discrete output capability by enabling eight solid-state relays via SN74LVC138ANSRG4 outputs. IC Role / Device Role / Timing Role: Demultiplexer converting serial command bits into parallel relay control signals, with G1 used as master enable for safety shutdown. Use Value: Dual enable architecture (G2A/G2B + G1) supports SIL-2 compliant fail-safe sequencing; ±24 mA drive matches SSR input requirements. |
Use Scenario: Selecting one of eight Modbus RTU slave nodes on a shared RS-485 bus using hardware address lines. IC Role / Device Role / Timing Role: Address decoder asserting unique EN signal to each node's transceiver, isolating communication to prevent bus contention. Use Value: Active-low outputs simplify connection to enable pins of RS-485 transceivers; 5.5 V tolerant inputs accept address switches wired to 5 V rails. |
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 at VCC < 4.5 V | Suitable for legacy 5 V-only systems; not recommended for 1.8 V or mixed-voltage designs | Choose SN74HC138N only if operating strictly at 5 V and timing budget exceeds 20 ns. |
| 74LVT138PW | 3.3 V only (3.0–3.6 V), higher drive (±32 mA), faster tpd (3.5 ns), but inputs not 5.5 V tolerant | Better for high-speed 3.3 V backplanes; requires external level shifters for 5 V control signals | Prefer 74LVT138PW when speed is critical and all upstream logic is 3.3 V compliant. |
Compared with SN74HC138N and 74LVT138PW, the SN74LVC138ANSRG4 uniquely balances wide supply range (1.65–3.6 V), 5.5 V input tolerance, and sub-6 ns delay-making it the only option qualified for direct 1.8 V/3.3 V/5 V interoperability without external components.
Availability
SN74LVC138ANSRG4 is available at Aetrix Electronics and suitable for LED displays, industrial I/O expansion, and factory automation systems requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.
Supply support for SN74LVC138ANSRG4 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 SN74LVC138ANSRG4 belongs to TI's LVC (Low-Voltage CMOS) logic family, engineered for low-power, high-speed operation in battery-powered and mixed-voltage embedded systems where voltage translation and timing precision are critical.
FAQ
What is the maximum propagation delay of the SN74LVC138ANSRG4 at 3.3 V?
The maximum propagation delay of the SN74LVC138ANSRG4 is 5.8 ns when measured from any enable or select input to any output (Y0–Y7) at VCC = 3.3 V ± 0.3 V and TA = 25°C. This value is confirmed in the Switching Characteristics table of the official TI datasheet SCAS291W. The SN74LVC138ANSRG4 achieves this performance while maintaining full 1.65–3.6 V supply compatibility.
Does the SN74LVC138ANSRG4 support 5 V input signals while powered from 1.8 V?
Yes, the SN74LVC138ANSRG4 accepts input voltages up to 5.5 V regardless of VCC, including when VCC = 1.8 V. This is explicitly specified in the "Features" and "Recommended Operating Conditions" sections of the TI datasheet. Inputs A, B, C, G1, G2A, and G2B are all 5.5 V tolerant, enabling direct interface with 5 V microcontrollers without level-shifting circuitry.
What package type and dimensions does the SN74LVC138ANSRG4 use?
The SN74LVC138ANSRG4 uses a 16-pin SOP (Small Outline Package) designated NS, with body dimensions of 9.90 mm × 3.91 mm and 1.27 mm lead pitch. It is RoHS-compliant, features NiPdAu lead finish, and has Moisture Sensitivity Level 1 (unlimited floor life at ≤30°C/60% RH). This package is compatible with standard surface-mount reflow processes per JEDEC J-STD-020.
How do the enable inputs G1, G2A, and G2B interact in the SN74LVC138ANSRG4?
In the SN74LVC138ANSRG4, all three enables must be simultaneously active for decoding: G1 must be HIGH, and both G2A and G2B must be LOW. If any enable is inactive, all outputs (Y0–Y7) go HIGH (inactive state). This triple-enable structure allows hierarchical control-e.g., G1 as system-level enable, G2A/G2B as board- or subsystem-level gating-reducing external logic in complex systems.
Can the SN74LVC138ANSRG4 be used as a demultiplexer, and how?
Yes, the SN74LVC138ANSRG4 functions as a 1-to-8 demultiplexer. By holding two select inputs constant and applying data to one enable input (e.g., G1), the data signal appears inverted on the selected output (Y0–Y7) while all others remain HIGH. For example, with A=B=C=0 and G2A=G2B=LOW, toggling G1 routes the signal to Y0. This mode is documented in TI's application note and functional description for the SN74LVC138ANSRG4.
SN74LVC138ANSRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 16-SOIC (0.209", 5.30mm 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-SO
SN74LVC138ANSRG4 FAQ
1.How can I place an order for SN74LVC138ANSRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC138ANSRG4 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 SN74LVC138ANSRG4 reliable?
The price and inventory of SN74LVC138ANSRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC138ANSRG4 is usually 5 days.
3.What payment methods are accepted for SN74LVC138ANSRG4?
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SN74LVC138ANSRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC138ANSRG4 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 SN74LVC138ANSRG4?
For technical support, including SN74LVC138ANSRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC138ANSRG4 requirements.
6.How does Aetrix verify that SN74LVC138ANSRG4 is sourced from the original manufacturer or authorized distributors?
All SN74LVC138ANSRG4 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 SN74LVC138ANSRG4 meets industry standards.
7.What is the process for return or replacement of SN74LVC138ANSRG4?
All SN74LVC138ANSRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC138ANSRG4, 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 SN74LVC138ANSRG4 part is unused and in its original packaging.
Return procedure for SN74LVC138ANSRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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