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Texas Instruments SN74AHC138DGVR
- Part No.:
- SN74AHC138DGVR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TFSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AHC138DGVR.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16TVSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,905
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Product details
Overview
SN74AHC138DGVR from Texas Instruments is a 3-line to 8-line decoder/demultiplexer in TVSOP-16 package, operating from 2 V to 5.5 V, with propagation delays as low as 5.7 ns (VCC = 5 V, CL = 15 pF), ±8 mA output drive, and three enable inputs (two active-low, one active-high) for cascading in memory decoding systems.
For engineers reviewing the SN74AHC138DGVR datasheet, SN74AHC138DGVR pinout, SN74AHC138DGVR application, or SN74AHC138DGVR equivalent, this page delivers verified electrical specs, functional pin roles, real-world use cases in address decoding and data routing, and validated alternative options for system design continuity.
Technical Context
The SN74AHC138DGVR implements positive-logic binary decoding with three address inputs (A0–A2) and three independent enables (G1, G2A, G2B), where only one of eight active-low outputs (Y0–Y7) asserts when all enables are satisfied. Its enable architecture allows direct demultiplexing - e.g., G1 can serve as data input while A2–A0 select output channel.
Designed for high-speed memory systems, it achieves sub-10 ns propagation delay at 3.3 V and sub-6 ns at 5 V under 15 pF load, with output drive capability sufficient to interface directly with AHC/AHCT logic families without buffering. Latch-up immunity exceeds 250 mA per JESD17.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 5.5 V - supports mixed-voltage system interfacing (e.g., 3.3 V microcontroller controlling 5 V peripheral address bus) |
| tPLH / tPHL (5 V, 15 pF) | 5.7 ns max - enables tight timing budgets in fast SRAM/ROM decoding paths without adding pipeline stages |
| IOL / IOH | ±8 mA at 5 V - drives up to 10 AHC loads or 20 LVTTL inputs without external buffers |
| Input Thresholds (VCC = 5 V) | VIH = 3.85 V, VIL = 1.65 V - ensures noise margin >0.7 V in industrial environments |
| ICC (Quiescent) | 40 μA max at 5.5 V - negligible power impact in always-on decode logic blocks |
| ESD Rating | 2000 V HBM, 1000 V CDM - meets IEC 61000-4-2 Level 2 for board-level robustness |
Pinout & Package
SN74AHC138DGVR uses a 16-pin Thin Very Small Outline Package (TVSOP, DGV), body size 3.6 mm × 4.4 mm, 0.65 mm pitch, with exposed thermal pad connected to GND or left floating per TI recommendation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0, A1, A2 | Binary address inputs | Select one of eight outputs; logic levels directly map to Y0–Y7 activation (e.g., A2A1A0 = 011 → Y3 low) |
| G1 | Active-high enable | Enables decoding when high; usable as serial data input in demux mode |
| G2A, G2B | Active-low enables | Both must be low to activate outputs; simplifies hierarchical decoding without external inverters |
| Y0–Y7 | Active-low decoded outputs | Only one asserts low per valid address/enable combination; open-drain behavior not supported - outputs are push-pull |
| VCC, GND | Power supply terminals | Decoupling capacitor (0.1 μF) required within 3 mm of VCC/GND pins to maintain switching integrity |
Key Features
| Feature | Design Value |
|---|---|
| Three enable inputs (G1, G2A, G2B) | Enables 24-line decoding without external inverters and 32-line with only one inverter - reduces BOM count and layout area |
| Propagation delay ≤5.7 ns (5 V) | Eliminates wait states in high-speed memory access cycles; effective system delay < memory access time |
| Latch-up immunity >250 mA | Withstands transient overcurrent events in shared-bus or hot-swap scenarios without destructive failure |
| Wide VCC range (2–5.5 V) | Interoperates across legacy 5 V, modern 3.3 V, and mixed-supply systems without level shifters |
| Input hysteresis not present | Requires clean, monotonic input transitions - floating inputs must be tied to VCC or GND to prevent oscillation |
Applications
| Memory Address Decoding | Peripheral Select Logic |
|---|---|
Use Scenario: Selecting one of eight SRAM chips in a 64 KB memory bank using upper address bits. IC Role / Device Role / Timing Role: 3-to-8 decoder mapping A15–A13 to chip-select lines, synchronized to memory enable strobe. Use Value: Delivers 5.7 ns propagation delay at 5 V, ensuring CS assertion occurs before memory access window closes. | Use Scenario: Routing UART, SPI, and I²C peripherals on an MCU-based industrial controller. IC Role / Device Role / Timing Role: Demultiplexer converting 3-bit peripheral ID bus into individual enable signals. Use Value: Active-low outputs directly drive enable pins of peripherals compliant with 3.3 V logic thresholds. |
| Bus Expansion Interface | Programmable Logic Glue |
Use Scenario: Expanding GPIO count on a microcontroller by enabling discrete latch ICs via decoded outputs. IC Role / Device Role / Timing Role: Decoder output Y0–Y7 gates clock/data enables to eight 8-bit latches (e.g., 74AHC573). Use Value: ±8 mA drive strength sustains signal integrity across 5 cm PCB traces to latch inputs. | Use Scenario: Replacing discrete NAND/NOR gates in FPGA configuration logic for legacy board redesign. IC Role / Device Role / Timing Role: Functionally implements 3-input AND-OR logic using enable-controlled output selection. Use Value: Reduces component count by 6–10 discrete gates while improving timing predictability and test coverage. |
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 |
|---|---|---|---|
| SN74LV138ADBR | Lower VCC range (1.65–5.5 V); 12 ns max tPD at 3.3 V; 6 mA drive | Better suited for battery-powered 3.3 V systems requiring ultra-low ICC (1 μA typ) | Choose for portable designs where quiescent current matters more than speed |
| 74HC138PW,118 | Same pinout; 20 ns max tPD at 4.5 V; 5.2 mA drive; non-AHC family | Compatible with legacy HC logic but lacks AHC's 2 V operation and ESD robustness | Use only when replacing existing HC-based designs with no voltage or noise margin changes |
Compared with SN74LV138ADBR and 74HC138PW,118, the SN74AHC138DGVR provides the fastest propagation delay (5.7 ns), widest supply range (2–5.5 V), and highest ESD tolerance - making it optimal for high-reliability, multi-voltage industrial control backplanes.
Availability
SN74AHC138DGVR is available at Aetrix Electronics and suitable for memory decoding, peripheral selection, bus expansion, and programmable logic glue applications requiring stable component supply and long-term industrial lifecycle support.
Supply support for SN74AHC138DGVR 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 delivering analog, embedded processing, and logic solutions with emphasis on reliability, performance, and broad application support.
The SN74AHC138DGVR belongs to TI's AHC logic family, engineered for high-speed, low-power memory decoding and data-routing in industrial, computing, and communications systems where timing precision and supply flexibility are critical.
FAQ
What is the maximum operating temperature for SN74AHC138DGVR?
The SN74AHC138DGVR has an operating free-air temperature range of −40 °C to +85 °C, qualified per JEDEC standards for commercial and industrial environments. This rating applies specifically to the DGV (TVSOP) package variant and is documented in Section 4.2 of the SCLS258N datasheet.
Does SN74AHC138DGVR support 2.5 V logic interfaces?
Yes, SN74AHC138DGVR operates down to 2 V VCC, making it fully compatible with 2.5 V systems. Input thresholds scale with VCC (VIH = 0.7×VCC, VIL = 0.3×VCC), so at 2.5 V, VIH = 1.75 V and VIL = 0.75 V - well within standard 2.5 V logic margins.
Can SN74AHC138DGVR outputs drive LEDs directly?
No - SN74AHC138DGVR outputs are push-pull with ±8 mA drive at 5 V, insufficient for typical indicator LEDs (requiring 10–20 mA). Direct LED driving risks exceeding absolute max output current (±25 mA) and degrading output voltage swing; a series resistor and buffer transistor or dedicated LED driver are required.
Is SN74AHC138DGVR pin-compatible with SN74HC138?
Yes, SN74AHC138DGVR shares identical pinout, function table, and package dimensions (TVSOP-16) with SN74HC138DBR. However, AHC offers faster speed, lower power, and wider VCC range; direct substitution is electrically valid but requires verifying timing margins in HC-designed circuits.
What is the thermal resistance (RθJA) of SN74AHC138DGVR?
The junction-to-ambient thermal resistance RθJA for SN74AHC138DGVR in the DGV (TVSOP) package is 120 °C/W, per Section 4.3 of the SCLS258N datasheet. This value assumes standard JEDEC 2-layer board conditions; actual performance improves with PCB copper pour under the thermal pad.
SN74AHC138DGVR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 16-TFSOP (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:
- 8mA, 8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TVSOP
SN74AHC138DGVR FAQ
1.How can I place an order for SN74AHC138DGVR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC138DGVR 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 SN74AHC138DGVR reliable?
The price and inventory of SN74AHC138DGVR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC138DGVR is usually 5 days.
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SN74AHC138DGVR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC138DGVR 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 SN74AHC138DGVR?
For technical support, including SN74AHC138DGVR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC138DGVR requirements.
6.How does Aetrix verify that SN74AHC138DGVR is sourced from the original manufacturer or authorized distributors?
All SN74AHC138DGVR 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 SN74AHC138DGVR meets industry standards.
7.What is the process for return or replacement of SN74AHC138DGVR?
All SN74AHC138DGVR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC138DGVR, 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 SN74AHC138DGVR part is unused and in its original packaging.
Return procedure for SN74AHC138DGVR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74AHC138DGVR Tags
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