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Nexperia USA Inc. 74HCT138PW,118
- Part No.:
- 74HCT138PW,118
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
74HCT138PW,118.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:8,431
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Product details
Overview
74HCT138PW,118 from Nexperia is a 3-to-8 line inverting decoder/demultiplexer with TTL-compatible inputs, operating from 4.5 V to 5.5 V, featuring three enable inputs (E1, E2 active LOW; E3 active HIGH), eight mutually exclusive active LOW outputs (Y0–Y7), and specified for -40 °C to +125 °C operation. It enables memory chip select decoding and scalable address expansion in industrial microcontroller systems.
For engineers reviewing the 74HCT138PW,118 datasheet, 74HCT138PW,118 pinout, 74HCT138PW,118 application, or 74HCT138PW,118 equivalent, key selection criteria include TTL-level input compatibility, propagation delay ≤53 ns at 5 V/CL = 50 pF, active LOW output polarity, multi-enable expansion capability, and TSSOP16 package thermal performance.
Technical Context
The 74HCT138PW,118 implements a combinational logic decoder with strict mutual exclusivity: only one output goes LOW when all enable conditions are met (E1 = LOW, E2 = LOW, E3 = HIGH) and a unique 3-bit address (A0–A2) is applied. Its enable architecture supports cascading-using E1/E2 as strobes and E3 as data input converts it into an 8-output demultiplexer.
Input clamping diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors. The device exhibits CMOS-level power efficiency (ICC ≤ 160 μA at 125 °C) while maintaining TTL input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V), ensuring robust noise immunity and legacy system 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. |
| Propagation Delay | ≤53 ns (max, An/E3 to Yn, VCC = 5 V, CL = 50 pF) - Supports reliable timing in sub-20 MHz address decoding and control path applications. |
| Input Thresholds | VIH = 2.0 V min, VIL = 0.8 V max - Guarantees clean recognition of TTL logic levels without level-shifting circuitry. |
| Output Polarity | Active LOW (Y0–Y7) - Directly drives enable inputs of memory ICs, peripherals, and LED drivers requiring low-asserted selection. |
| Operating Temperature | -40 °C to +125 °C - Qualified for under-hood, motor control, and industrial PLC environments without derating. |
| Power Dissipation | Ptot = 500 mW (TSSOP16); derates 8.5 mW/K above 91 °C - Enables sustained operation in compact, thermally constrained PCB layouts. |
| ESD Protection | HBM >2000 V, CDM >1000 V - Reduces risk of handling damage during SMT assembly and field service. |
Pinout & Package
TSSOP16 plastic thin shrink small outline package (SOT403-1), 16-pin, body width 4.4 mm, 0.65 mm pitch, exposed pad not electrically connected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A0) | Address Input LSB | Binary weight 2⁰; determines output selection parity when combined with A1/A2. |
| 2 (A1) | Address Input | Binary weight 2¹; forms 3-bit address with A0 and A2 for Y0–Y7 mapping. |
| 3 (A2) | Address Input MSB | Binary weight 2²; completes 3-bit decode word; all three must be stable before enable assertion. |
| 4 (E1) | Enable Input (active LOW) | Primary global disable; tied LOW to activate decoder; used with E2/E3 for hierarchical enable tree. |
| 5 (E2) | Enable Input (active LOW) | Secondary enable; both E1 and E2 must be LOW for any output to activate. |
| 6 (E3) | Enable Input (active HIGH) | Third enable; must be HIGH to permit decoding; used as data input in demux mode. |
| 7 (Y7) | Output (active LOW) | Asserts LOW when A2A1A0 = 111 and enables satisfied; drives memory CS#, peripheral EN, or LED cathode. |
| 8 (GND) | Ground Reference | 0 V return path for all internal logic and output currents; requires low-impedance PCB plane connection. |
| 9 (Y6) | Output (active LOW) | Asserts LOW for A2A1A0 = 110; shares same timing and drive strength as other Y outputs. |
| 10 (Y5) | Output (active LOW) | Asserts LOW for A2A1A0 = 101; identical DC/AC characteristics across all eight outputs. |
| 11 (Y4) | Output (active LOW) | Asserts LOW for A2A1A0 = 100; no bus contention due to strictly mutually exclusive activation. |
| 12 (Y3) | Output (active LOW) | Asserts LOW for A2A1A0 = 011; supports wired-OR expansion when multiple decoders share outputs. |
| 13 (Y2) | Output (active LOW) | Asserts LOW for A2A1A0 = 010; compatible with 74-series fan-out requirements (IOH/IOL ≥ ±4 mA). |
| 14 (Y1) | Output (active LOW) | Asserts LOW for A2A1A0 = 001; VOL ≤ 0.4 V at 4 mA ensures solid LOW-level interface to downstream CMOS/TTL inputs. |
| 15 (Y0) | Output (active LOW) | Asserts LOW for A2A1A0 = 000; default selection output; commonly used for boot device or primary peripheral enable. |
| 16 (VCC) | Supply Voltage | +4.5 V to +5.5 V power rail; bypass capacitor (100 nF ceramic) required within 5 mm of pin for noise suppression. |
Key Features
| Feature | Design Value |
|---|---|
| Multiple Enable Architecture | E1/E2 (LOW) + E3 (HIGH) enables decoding; allows daisy-chaining up to five 74HCT138s for 1-of-32 decoding with one external inverter. |
| Demultiplexing Mode | Using E3 as data input and E1/E2 as strobes configures the device as an 8-output demux-no additional logic required. |
| TTL-Compatible Inputs | VIH ≥ 2.0 V and VIL ≤ 0.8 V at 5 V supply eliminates need for level shifters when interfacing with legacy 74LS or microcontroller GPIO. |
| Clamped Inputs | Integrated input clamp diodes permit safe overvoltage tolerance (e.g., 12 V signals) when series current-limiting resistors are used. |
| Industrial Temperature Range | Specified from -40 °C to +125 °C with full parameter guarantees-supports deployment in motor drives, power supplies, and factory automation. |
Applications
| Memory Address Decoding | Peripheral Select Logic |
|---|---|
|
Use Scenario: Selecting one of eight SRAM, EPROM, or flash memory chips in a microcontroller-based embedded system with limited address lines. IC Role / Device Role / Timing Role: Translates 3-bit address subset (A0–A2) into individual chip-select signals (CS#), enabling banked memory access without FPGA or CPLD. Use Value: Eliminates discrete logic gates or larger programmable devices; reduces BOM count and PCB area while guaranteeing deterministic, glitch-free selection timing. |
Use Scenario: Enabling specific sensors, ADCs, DACs, or communication interfaces (e.g., SPI slaves) on a shared bus in an industrial data acquisition module. IC Role / Device Role / Timing Role: Acts as a static peripheral selector-outputs drive /CS pins of up to eight devices, synchronized to address setup/hold windows. Use Value: Provides predictable, low-jitter enable timing (tpd ≤ 53 ns) and eliminates software overhead of GPIO-based chip selection. |
| LED Segment Driver Control | System Boot Configuration |
|
Use Scenario: Driving common-anode 7-segment displays or discrete status LEDs in HVAC controllers or HMI panels where active LOW segments simplify current-sinking driver design. IC Role / Device Role / Timing Role: Outputs directly sink LED current (up to 4 mA per Y pin) when paired with series resistors; no external transistors needed for low-current indicators. Use Value: Reduces component count versus discrete transistor arrays; leverages built-in output drive strength and guaranteed VOL < 0.4 V for bright, consistent LED illumination. |
Use Scenario: Configuring boot source (e.g., NOR flash, NAND flash, SD card, or UART bootloader) in a dual-BIOS or fail-safe firmware architecture. IC Role / Device Role / Timing Role: Y0–Y7 assert during power-on reset to enable corresponding boot device interface; E1/E2/E3 controlled by strap pins or configuration EEPROM. Use Value: Enables hardware-selectable boot paths with zero software dependency-critical for recovery and field-upgrade reliability. |
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 |
|---|---|---|---|
| 74HC138PW,118 | CMOS-level inputs (VIH = 3.15 V min at 4.5 V); wider 2.0–6.0 V supply range; higher propagation delay (≤139 ns at 2 V) | Better suited for mixed-voltage systems (e.g., 3.3 V MCU + 5 V peripherals) but incompatible with pure TTL logic families | Select when system uses CMOS I/O or requires extended VCC range beyond 5 V |
| SN74LS138N | Bipolar TTL process; VIH = 2.0 V, VIL = 0.8 V same as 74HCT138; but higher ICC (≈40 mA), lower noise immunity, and obsolete through-hole only (PDIP16) | Legacy board replacements only; unsuitable for new designs due to power, thermal, and RoHS constraints | Use only for repair of vintage equipment; avoid for new industrial or automotive designs |
Compared with 74HC138PW,118 and SN74LS138N, the 74HCT138PW,118 uniquely balances TTL input compatibility, low power (μA-range ICC), modern TSSOP packaging, and industrial temperature support-making it the optimal choice for new 5 V embedded control designs requiring reliability and scalability.
Availability
74HCT138PW,118 is available at Aetrix Electronics and suitable for memory decoding, peripheral selection, LED control, and boot configuration requiring stable component supply across industrial temperature grades and long-lifecycle production programs.
Supply support for 74HCT138PW,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 leading semiconductor manufacturer specializing in high-performance, energy-efficient logic, analog, and discrete components, headquartered in Nijmegen, Netherlands.
The 74HCT138 belongs to Nexperia's industry-standard 74HCT logic family, designed specifically to bridge TTL and CMOS systems with robust noise immunity, wide operating margins, and drop-in compatibility for legacy 74LS designs.
FAQ
Can the 74HCT138PW,118 operate at 3.3 V?
No. The 74HCT138PW,118 is specified only for 4.5 V to 5.5 V supply voltage. At 3.3 V, its TTL input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) become unreliable, and output drive strength degrades significantly. For 3.3 V systems, use the 74LVC138 or 74AHC138 instead.
What is the maximum capacitive load each output can drive reliably?
Each Y output is characterized up to 50 pF load capacitance (per dynamic specs). With CL = 50 pF and VCC = 5 V, tpd remains ≤53 ns and tt ≤22 ns. Driving >50 pF increases propagation delay nonlinearly and may cause signal integrity issues-add a buffer for loads exceeding 75 pF.
Is the TSSOP16 package (SOT403-1) lead-free and RoHS compliant?
Yes. The 74HCT138PW,118 uses a lead-free, halogen-free, RoHS-compliant TSSOP16 package (SOT403-1) with matte tin finish on leads, qualified to JEDEC J-STD-020 moisture sensitivity level 1 (unlimited floor life at ≤30 °C/85 % RH).
How does the enable logic prevent partial output activation?
The 74HCT138PW,118 requires all three enables simultaneously: E1 = LOW, E2 = LOW, and E3 = HIGH. If any enable condition fails, all eight outputs remain HIGH (inactive). This triple-guard logic eliminates glitches during enable transitions and ensures only one output activates per valid address.
74HCT138PW,118 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- 74HCT
- 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:
- 4mA, 4mA
- 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
74HCT138PW,118 FAQ
1.How can I place an order for 74HCT138PW,118 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HCT138PW,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 74HCT138PW,118 reliable?
The price and inventory of 74HCT138PW,118 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HCT138PW,118 is usually 5 days.
3.What payment methods are accepted for 74HCT138PW,118?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HCT138PW,118 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HCT138PW,118?
74HCT138PW,118 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HCT138PW,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 74HCT138PW,118?
For technical support, including 74HCT138PW,118 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HCT138PW,118 requirements.
6.How does Aetrix verify that 74HCT138PW,118 is sourced from the original manufacturer or authorized distributors?
All 74HCT138PW,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 74HCT138PW,118 meets industry standards.
7.What is the process for return or replacement of 74HCT138PW,118?
All 74HCT138PW,118 units undergo pre-shipment inspection (PSI). If there is an issue with 74HCT138PW,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 74HCT138PW,118 part is unused and in its original packaging.
Return procedure for 74HCT138PW,118:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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