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Nexperia USA Inc. 74AHCT138PW,118
- Part No.:
- 74AHCT138PW,118
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
74AHCT138PW,118.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,475
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Product details
Overview
74AHCT138PW,118 from Nexperia is a TTL-level-compatible 3-to-8 line inverting decoder/demultiplexer in TSSOP16 package, operating from 4.5 V to 5.5 V, delivering 8 mutually exclusive active-low outputs (Y0–Y7), with propagation delay as low as 4.2 ns at 5 V and 50 pF load, used for memory chip select decoding and address expansion in industrial microcontroller systems.
For engineers reviewing the 74AHCT138PW,118 datasheet, 74AHCT138PW,118 pinout, 74AHCT138PW,118 application, or 74AHCT138PW,118 equivalent, key selection considerations include TTL input compatibility (VIH = 2.0 V min, VIL = 0.8 V max), -40 °C to +125 °C operation, enable-input logic (E1/E2 active LOW, E3 active HIGH), and output drive capability (IO = ±8 mA).
Technical Context
The device implements a fully decoded 3-bit binary address (A0–A2) into eight independent active-low outputs, with three enable inputs enabling hierarchical cascading-two active-low (E1, E2) and one active-high (E3)-ensuring all outputs remain HIGH unless E1 = E2 = LOW and E3 = HIGH. This architecture supports parallel expansion to 1-of-32 decoding using four units and one inverter.
It features Schmitt-trigger inputs for noise immunity, operates with TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V at VCC = 4.5–5.5 V), and guarantees rail-to-rail output swing (VOH ≥ 3.94 V, VOL ≤ 0.36 V at IO = ±8 mA, VCC = 4.5 V), meeting JEDEC Std. 7A for LSTTL pin compatibility.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL and mixed-voltage industrial logic systems |
| Input Thresholds | VIH ≥ 2.0 V, VIL ≤ 0.8 V - guarantees reliable recognition of legacy TTL logic levels without level-shifting |
| Propagation Delay | 4.2 ns (min) / 13.5 ns (max) at VCC = 5 V, CL = 50 pF - enables high-speed address decoding in real-time control subsystems |
| Output Drive | ±8 mA - sufficient to directly drive multiple LS-TTL inputs or small LED indicators without buffering |
| Operating Temperature | -40 °C to +125 °C - qualified for under-hood, motor control, and industrial PLC environments |
| Power Dissipation | CPD = 23.0 pF - allows accurate dynamic power estimation (PD = CPD × VCC² × fi × N) for thermal budgeting |
| ESD Robustness | HBM > 2000 V, CDM > 1000 V - meets IEC 61000-4-2 system-level robustness requirements |
Pinout & Package
TSSOP16 package (SOT403-1): plastic thin shrink small outline, 16 leads, 4.4 mm body width, 0.65 mm pitch, exposed pad not electrically connected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A0) | Address input | LSB of 3-bit binary address; sampled synchronously with enable conditions to determine output activation |
| 2 (A1) | Address input | Middle bit of address; combined with A0/A2 to uniquely select one of eight outputs |
| 3 (A2) | Address input | MSB of address; determines upper/lower half of output group (Y0–Y3 vs Y4–Y7) |
| 4 (E1) | Enable input | Active-LOW global enable; must be LOW with E2 for any output to activate |
| 5 (E2) | Enable input | Active-LOW secondary enable; both E1 and E2 must be LOW while E3 is HIGH for decode operation |
| 6 (E3) | Enable input | Active-HIGH tertiary enable; provides polarity flexibility for cascaded enable tree design |
| 7 (Y0) | Output | Active-LOW decoded output for address 000; sinks current when selected, floats HIGH otherwise |
| 8 (GND) | Ground | 0 V reference for all input thresholds and output voltage levels; requires low-impedance PCB connection |
| 9 (Y7) | Output | Active-LOW decoded output for address 111; complements Y0–Y6 in full 3-bit decode map |
| 10 (Y5) | Output | Active-LOW output for address 101; shares timing characteristics and drive strength with all Yx outputs |
| 11 (Y4) | Output | Active-LOW output for address 100; used in memory bank selection where Y4–Y7 map to upper 4 KB regions |
| 12 (Y3) | Output | Active-LOW output for address 011; commonly assigned to peripheral I/O decode space |
| 13 (Y2) | Output | Active-LOW output for address 010; supports demultiplexing when E1 used as data input |
| 14 (Y1) | Output | Active-LOW output for address 001; pairs with Y0 for dual-channel interrupt routing |
| 15 (Y6) | Output | Active-LOW output for address 110; enables 1-of-8 signal routing in test equipment multiplexers |
| 16 (VCC) | Supply | +4.5 V to +5.5 V power rail; requires local 100 nF ceramic decoupling adjacent to pin |
Key Features
| Feature | Design Value |
|---|---|
| Schmitt-trigger inputs | Provides 0.5 V typical hysteresis on all address and enable pins, rejecting noise spikes up to 5 ns duration in industrial EMI environments |
| TTL input compatibility | Guarantees VIH ≥ 2.0 V and VIL ≤ 0.8 V across full temperature range, eliminating need for external level translators in 5 V legacy systems |
| Three-enable architecture | Enables hierarchical decoding: E1/E2 serve as group enables, E3 as channel enable-supporting 1-of-32 expansion with minimal external logic |
| Inverting active-low outputs | All Y0–Y7 assert LOW when selected, directly interfacing with active-low chip selects (e.g., SRAM /CS, Flash /CE) without inverters |
| Wide temperature operation | Specified from -40 °C to +125 °C with no derating, supporting deployment in motor drives and power converters without thermal margin loss |
Applications
| Memory Address Decoding | Industrial I/O Expansion |
|---|---|
Use Scenario: Selecting among eight SRAM or Flash memory chips in a microcontroller-based data logger with 64 KB address space. IC Role / Device Role / Timing Role: Acts as address-space partitioner, translating A0–A2 and chip-enable strobes into individual /CS signals with <13.5 ns propagation delay. Use Value: Eliminates discrete gate logic, reduces board area by 40% versus NAND-based decoders, and ensures deterministic setup/hold timing for 20 MHz bus cycles. | Use Scenario: Routing control signals from a single microcontroller port to eight isolated relay drivers in a programmable logic controller (PLC) backplane. IC Role / Device Role / Timing Role: Functions as demultiplexer: E1 serves as data input, A0–A2 as select lines, Y0–Y7 as routed command outputs. Use Value: Enables single-wire serial control of eight relays with precise 4.2 ns minimum edge-to-output timing, reducing GPIO count by 7 pins. |
| Microcontroller Peripheral Selection | Test Equipment Signal Routing |
Use Scenario: Assigning unique chip-select lines to UART, SPI, I²C, ADC, DAC, CAN, PWM, and watchdog peripherals on an ARM Cortex-M4 evaluation board. IC Role / Device Role / Timing Role: Provides mutually exclusive enable signals synchronized to address decode cycle; E3 tied to /RD, E1/E2 to address MSBs. Use Value: Guarantees no bus contention during peripheral access; VOL ≤ 0.36 V ensures >400 mV noise margin driving 10 LS-TTL loads. | Use Scenario: Switching between eight calibration reference voltages in automated test equipment (ATE) during self-test sequences. IC Role / Device Role / Timing Role: Serves as precision analog multiplexer controller: Yx outputs drive MOSFET gates to connect references to DUT input. Use Value: Propagation delay variation <1.5 ns across all outputs ensures sub-ns skew in reference switching, critical for 16-bit DAC linearity verification. |
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 |
|---|---|---|---|
| SN74LS138N | Lower speed (tPD ≈ 22 ns), higher ICC (19 mA), TTL-only supply (4.75–5.25 V), no Schmitt triggers | Legacy 5 V systems with relaxed timing; unsuitable for -40 °C to +125 °C or low-noise environments | Select only if replacing existing LS138 designs with no timing or temperature upgrades required |
| 74HC138PW,118 | CMOS input thresholds (VIH = 3.85 V at VCC = 5.5 V), slower propagation (min 5.5 ns), lower drive (±4 mA) | Low-power 3.3 V/5 V mixed-signal systems where TTL compatibility is unnecessary | Prefer when interfacing with CMOS microcontrollers and power budget is constrained below 10 μA ICC |
Compared with SN74LS138N, 74AHCT138PW,118 offers 2× faster timing and extended temperature range but requires identical 5 V rail; versus 74HC138PW,118, it trades CMOS input sensitivity for guaranteed TTL interoperability and stronger output drive-critical for driving legacy loads.
Availability
74AHCT138PW,118 is available at Aetrix Electronics and suitable for memory address decoding, industrial I/O expansion, microcontroller peripheral selection, and test equipment signal routing requiring stable component supply across automotive-grade temperature ranges and long production lifecycles.
Supply support for 74AHCT138PW,118 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
Nexperia is a global semiconductor expert headquartered in Nijmegen, Netherlands, specializing in high-volume logic, analog, and discrete components with focus on reliability, efficiency, and manufacturability.
This device belongs to Nexperia's 74AHCT advanced high-speed CMOS logic family, engineered specifically for seamless migration from LS-TTL systems while delivering improved noise immunity, wider temperature operation, and lower power consumption.
FAQ
What is the maximum clock frequency supported by the 74AHCT138PW,118?
The 74AHCT138PW,118 is not a clocked device-it has no internal clock and operates asynchronously on input transitions. Its usable switching rate is determined by propagation delay (as low as 4.2 ns) and input transition rate (≤20 ns/V at VCC = 5 V), enabling reliable operation with address/data edges up to ~100 MHz in well-terminated systems.
Can the 74AHCT138PW,118 be used with a 3.3 V supply?
No. The 74AHCT138PW,118 is specified only for 4.5 V to 5.5 V operation per its Recommended Operating Conditions table. At 3.3 V, VIH (2.0 V min) would exceed 60% of VCC, violating input threshold ratios and risking unreliable decoding; use 74AHC138PW,118 instead for 3.3 V systems.
How should unused enable inputs be terminated?
Unused enable inputs must be permanently tied to their defined active state: E1 and E2 to GND (active LOW), E3 to VCC (active HIGH). Floating enables cause indeterminate output states and increased ICC due to input stage contention; verified worst-case ICC rises from 4 μA to >40 μA when E1/E2 float near 1.5 V.
Is the TSSOP16 package RoHS-compliant and lead-free?
Yes. The 74AHCT138PW,118 in SOT403-1 (TSSOP16) package is manufactured per Nexperia's lead-free and RoHS-compliant process, with SnAgCu (SAC305) solder finish, compliant with JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1), and rated for peak reflow temperatures up to 260 °C.
74AHCT138PW,118 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- 74AHCT
- 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:
- 8mA, 8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
74AHCT138PW,118 FAQ
1.How can I place an order for 74AHCT138PW,118 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AHCT138PW,118 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 74AHCT138PW,118 reliable?
The price and inventory of 74AHCT138PW,118 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AHCT138PW,118 is usually 5 days.
3.What payment methods are accepted for 74AHCT138PW,118?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AHCT138PW,118 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74AHCT138PW,118?
74AHCT138PW,118 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AHCT138PW,118 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 74AHCT138PW,118?
For technical support, including 74AHCT138PW,118 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AHCT138PW,118 requirements.
6.How does Aetrix verify that 74AHCT138PW,118 is sourced from the original manufacturer or authorized distributors?
All 74AHCT138PW,118 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 74AHCT138PW,118 meets industry standards.
7.What is the process for return or replacement of 74AHCT138PW,118?
All 74AHCT138PW,118 units undergo pre-shipment inspection (PSI). If there is an issue with 74AHCT138PW,118, 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 74AHCT138PW,118 part is unused and in its original packaging.
Return procedure for 74AHCT138PW,118:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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