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Texas Instruments SN74AHC138PWR-P
- Part No.:
- SN74AHC138PWR-P
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AHC138PWR-P.pdf
- Description:
- PROTOTYPE
- Quantity:
- Payment:
- Shipping:
Inventory:3,219
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Product details
Overview
SN74AHC138PWR-P from Texas Instruments is a 3-line to 8-line decoder/demultiplexer in TSSOP-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 SN74AHC138PWR-P datasheet, SN74AHC138PWR-P pinout, SN74AHC138PWR-P application, or SN74AHC138PWR-P equivalent, this page delivers verified functional role, real-world timing performance, cascade-enabling logic architecture, thermal resistance (135.9 °C/W), and validated alternative options for high-speed address decoding and data routing.
Technical Context
The SN74AHC138PWR-P implements positive-logic binary decoding with three address inputs (A0–A2) and three independent enables (G1, G2A, G2B), where outputs Y0–Y7 are active-low and mutually exclusive. Its enable architecture allows direct 24-line expansion without external inverters and supports demultiplexing via G1 or G2B as data inputs.
Designed for high-speed memory systems, it achieves sub-10 ns propagation delay at 5 V and maintains rail-to-rail output swing across its full 2–5.5 V supply range. Input thresholds scale with VCC (VIH = 0.7×VCC, VIL = 0.3×VCC), ensuring robust noise immunity in mixed-voltage digital interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 5.5 V - supports direct interface with 3.3 V and 5 V logic families without level shifters. |
| tPLH / tPHL (5 V, CL = 15 pF) | 5.7 ns max - enables use in address decode paths of fast SRAMs and FPGAs with ≤10 ns access time. |
| IOL / IOH | ±8 mA at 5 V - drives standard TTL loads and multiple CMOS inputs without buffering. |
| Input Thresholds | VIH = 0.7×VCC, VIL = 0.3×VCC - ensures reliable switching across voltage rails and temperature (−40°C to +85°C). |
| ICC (Quiescent) | 40 μA max at 5.5 V - enables low-static-power operation in battery-backed or always-on control logic. |
| ESD Rating | HBM: 2000 V, CDM: 1000 V - meets industrial handling requirements without additional protection circuitry. |
Pinout & Package
TSSOP-16 package (PW), 5.0 mm × 6.4 mm body size, 1.2 mm max height, lead finish NIPDAU/SN, MSL Level-1, RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A0) | Address input | LSB of 3-bit binary address; determines output selection when enables are active. |
| 2 (A1) | Address input | Middle bit of address; combined with A0/A2, selects one of eight decoded outputs. |
| 3 (A2) | Address input | MSB of address; required for full 3-to-8 decoding functionality. |
| 4 (G̅0) | Active-low enable | Global strobe: all outputs forced high when high; must be low for decoding to occur. |
| 5 (G1) | Active-high enable | Primary enable: used as data input in demux mode; output state follows G1 when other enables active. |
| 6 (G̅2) | Active-low enable | Secondary enable: complements G̅0 to reduce external gate count in multi-chip decode trees. |
| 7–15 (Y7–Y0) | Active-low outputs | One-hot decoded outputs; only one low at a time when all enables satisfied and address valid. |
| 8 (GND) | Ground reference | Return path for all internal logic and output current; must be low-impedance for timing integrity. |
| 16 (VCC) | Power supply | Single-supply rail powering all logic; decoupling capacitor (0.1 μF) required within 1 cm of pin. |
Key Features
| Feature | Design Value |
|---|---|
| Three enable inputs (G1, G̅0, G̅2) | Enables 24-line decoding without external inverters and simplifies hierarchical memory map design. |
| Propagation delay ≤5.7 ns @ 5 V | Minimizes system-level address decode latency, critical for high-speed SRAM and FPGA configuration buses. |
| Rail-to-rail output swing | Ensures full logic-level compatibility with downstream 5 V TTL and 3.3 V CMOS receivers. |
| Latch-up immunity >250 mA | Guarantees robust operation under transient overvoltage or ESD events in industrial environments. |
| Low ICC (40 μA max) | Reduces standby power in microcontroller-based peripheral decoders and always-on I/O expanders. |
Applications
| Memory Address Decoding | FPGA Peripheral Selection |
|---|---|
Use Scenario: Selecting one of eight SRAM or ROM chips in a 64 KB memory bank using A15–A13 as address lines. IC Role / Device Role / Timing Role: 3-to-8 address decoder providing chip-select signals with <10 ns delay to meet SRAM access timing. Use Value: Eliminates need for discrete NAND gates or CPLD logic, reducing BOM count and PCB area by 30% in compact embedded controllers. |
Use Scenario: Routing configuration data from an FPGA's general-purpose I/O to eight distinct sensor interface ICs. IC Role / Device Role / Timing Role: Demultiplexer using G1 as serial data input and A2–A0 as channel select, enabling 1-to-8 parallel distribution. Use Value: Provides deterministic, glitch-free channel selection with no clock domain crossing, supporting 100 MHz SPI-based sensor polling. |
| Industrial PLC I/O Expansion | Automotive Body Control Module |
Use Scenario: Expanding microcontroller GPIO to drive 8 relay drivers in a programmable logic controller rack. IC Role / Device Role / Timing Role: Decoder enabling individual relay activation via 3-bit command bus; outputs directly interface ULN2803 drivers. Use Value: Delivers ±8 mA sink capability per output, eliminating external transistor stages and improving reliability in 24 V DC control environments. |
Use Scenario: Selecting among eight LIN transceiver channels for distributed door module diagnostics in a vehicle network. IC Role / Device Role / Timing Role: Address decoder synchronizing with microcontroller's wake-up interrupt to activate specific LIN node before bus arbitration. Use Value: Supports fast wake-up response (<15 ns propagation) and operates reliably across −40°C to +85°C ambient, meeting automotive qualification requirements. |
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 |
|---|---|---|---|
| SN74HC138PWR | Slower propagation (19 ns @ 5 V), lower drive (±4 mA), same pinout and function. | Suitable for cost-sensitive, lower-speed systems (≤10 MHz bus clocks) where timing margin is ample. | Select when BOM cost priority outweighs speed; verify timing closure with worst-case 19 ns delay. |
| 74LVC138APW,118 | Wider VCC range (1.65–5.5 V), faster (3.5 ns @ 3.3 V), but only rated to +125°C junction (not ambient). | Better for mixed-voltage 1.8 V/3.3 V systems and extended-temperature industrial controls. | Prefer for new designs requiring 1.8 V compatibility or tighter timing budgets; confirm thermal derating above 85°C ambient. |
Compared with SN74HC138PWR and 74LVC138APW,118, the SN74AHC138PWR-P delivers optimal balance of speed (5.7 ns), drive strength (±8 mA), and industrial temperature support (−40°C to +85°C) without sacrificing pin compatibility or supply flexibility.
Availability
SN74AHC138PWR-P is available at Aetrix Electronics and suitable for memory decoding, FPGA peripheral selection, industrial PLC I/O expansion, and automotive body control modules requiring stable component supply and long-term production continuity.
Supply support for SN74AHC138PWR-P 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 logic solutions, with over 50 years of innovation in high-reliability digital ICs.
The SN74AHC138PWR-P belongs to TI's advanced high-speed CMOS (AHC) logic family, engineered specifically for low-propagation-delay memory decoding and data-routing applications in industrial, computing, and communications systems.
FAQ
What is the maximum operating frequency supported by SN74AHC138PWR-P?
The SN74AHC138PWR-P is not a clocked device and has no specified maximum operating frequency. Its usable switching rate depends on propagation delay (5.7 ns min @ 5 V) and system-level timing margins. For reliable operation, input address and enable transitions must settle ≥10 ns before output stabilization, supporting effective decode rates up to ~80 MHz in well-designed layouts with controlled trace impedance and proper decoupling.
Can SN74AHC138PWR-P operate at 1.8 V supply?
No, SN74AHC138PWR-P is not rated for 1.8 V operation. Its absolute minimum VCC is 2 V per datasheet Section 4.2, and input thresholds (VIH = 0.7×VCC, VIL = 0.3×VCC) would fall outside 1.8 V logic levels. For 1.8 V systems, consider 74LVC138APW,118 or SN74AUP1G138 - both explicitly characterized down to 1.65 V.
How does the enable logic of SN74AHC138PWR-P support cascading?
The SN74AHC138PWR-P uses three enables - G1 (active-high), G̅0 (active-low), and G̅2 (active-low) - to simplify multi-chip decoding. In a 24-line scheme, outputs of a master SN74AHC138PWR-P drive G̅0/G̅2 of three slave devices, while G1 remains tied high. This eliminates external inverters and reduces gate count by 6 compared to HC-series alternatives.
Is SN74AHC138PWR-P pin-compatible with SN74HC138PWR?
Yes, SN74AHC138PWR-P and SN74HC138PWR share identical TSSOP-16 pinout, pin functions, and footprint. However, SN74AHC138PWR-P offers 2.5× faster propagation delay (5.7 ns vs. 19 ns @ 5 V) and double the output drive (±8 mA vs. ±4 mA), making it a performance upgrade with no PCB changes required.
What thermal considerations apply to SN74AHC138PWR-P in continuous operation?
SN74AHC138PWR-P has a junction-to-ambient thermal resistance (RθJA) of 135.9 °C/W in TSSOP-16. At 5 V and full output loading (8 mA × 8 outputs = 64 mA), power dissipation reaches ~320 mW, raising junction temperature by ~43°C above ambient. Maintain ambient ≤70°C and provide ≥1 cm² copper pour under the thermal pad (if connected to GND) to ensure safe operation within the −40°C to +85°C rating.
SN74AHC138PWR-P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- 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-TSSOP
SN74AHC138PWR-P FAQ
1.How can I place an order for SN74AHC138PWR-P through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC138PWR-P 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 SN74AHC138PWR-P reliable?
The price and inventory of SN74AHC138PWR-P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC138PWR-P is usually 5 days.
3.What payment methods are accepted for SN74AHC138PWR-P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC138PWR-P transactions.
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4.How is shipping managed for SN74AHC138PWR-P?
SN74AHC138PWR-P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC138PWR-P 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 SN74AHC138PWR-P?
For technical support, including SN74AHC138PWR-P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC138PWR-P requirements.
6.How does Aetrix verify that SN74AHC138PWR-P is sourced from the original manufacturer or authorized distributors?
All SN74AHC138PWR-P 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 SN74AHC138PWR-P meets industry standards.
7.What is the process for return or replacement of SN74AHC138PWR-P?
All SN74AHC138PWR-P units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC138PWR-P, 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 SN74AHC138PWR-P part is unused and in its original packaging.
Return procedure for SN74AHC138PWR-P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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