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Nexperia USA Inc. 74AHCT138D-Q100J
- Part No.:
- 74AHCT138D-Q100J
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
74AHCT138D-Q100J.pdf
- Description:
- IC DECODER/DEMUX 1 X 3:8 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,063
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Product details
Overview
74AHCT138D-Q100 from Nexperia is an automotive-grade 3-to-8 line inverting decoder/demultiplexer in SO16 package, operating from 4.5 V to 5.5 V with TTL-compatible inputs, 8 mutually exclusive active-low outputs (Y0–Y7), and three enable inputs (E1, E2 active LOW; E3 active HIGH) for parallel expansion in memory chip select and address decoding applications.
For engineers reviewing the 74AHCT138D-Q100 datasheet, 74AHCT138D-Q100 pinout, 74AHCT138D-Q100 application, or 74AHCT138D-Q100 equivalent, this device supports automotive AEC-Q100 Grade 1 qualification, offers balanced propagation delays down to 4.2 ns (VCC = 5 V, CL = 15 pF), and enables 1-of-32 decoding via cascading with minimal external logic.
Technical Context
The 74AHCT138D-Q100 implements a fully static CMOS decoder architecture with Schmitt-trigger inputs, supporting TTL-level input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V) and delivering rail-to-rail output swing under load. Its enable logic (E1 AND E2 AND NOT E3) ensures deterministic output states across temperature.
Propagation delay is specified per input path: An→Yn, E3→Yn, and E1/E2→Yn, with worst-case tpd ≤ 13.5 ns over -40 °C to +125 °C at CL = 50 pF and VCC = 5 V. Power dissipation capacitance is 23.0 pF, enabling accurate dynamic power estimation using CPD × VCC² × fi × N.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with 5 V TTL systems and stable operation across automotive battery transients. |
| Input Thresholds | VIH ≥ 2.0 V, VIL ≤ 0.8 V - Guarantees robust noise immunity and direct interfacing with standard TTL outputs without level shifting. |
| Propagation Delay | 4.2 ns (typ, VCC = 5 V, CL = 15 pF) - Enables high-speed address decoding in microcontroller peripheral selection and FPGA I/O expansion. |
| Output Drive | ±8 mA (VOH/VOL @ VCC = 4.5 V) - Sufficient to drive multiple LSTTL inputs or small capacitive loads without buffering. |
| Operating Temperature | -40 °C to +125 °C - Qualified for under-hood automotive environments including engine control units and ADAS domain controllers. |
| AEC-Q100 Grade | Grade 1 - Certified for automotive use with full reliability testing including HTOL, TC, and ESD (HBM > 2000 V, CDM > 1000 V). |
| Power Dissipation Cap. | 23.0 pF - Allows precise dynamic power calculation (PD = CPD × VCC² × fi × N) for thermal budgeting in dense PCB layouts. |
Pinout & Package
74AHCT138D-Q100 uses the SO16 plastic small outline package (SOT109-1), 16-pin, 3.9 mm body width, with gull-wing leads and JEDEC MS-012 compliance. Pin 1 index located at top-left corner with notch marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A0) | Address input LSB | Binary-weighted input accepting TTL logic levels; determines output Y0–Y1 pair selection when enabled. |
| 2 (A1) | Address input middle bit | Second binary address bit; combined with A0 and A2, selects one of eight outputs exclusively. |
| 3 (A2) | Address input MSB | Most significant address bit; completes 3-bit decode map (000–111) to Y0–Y7 activation sequence. |
| 4 (E1) | Enable input (active LOW) | Primary global enable; must be LOW with E2 LOW and E3 HIGH for any output to go LOW. |
| 5 (E2) | Enable input (active LOW) | Secondary enable; both E1 and E2 must be asserted LOW simultaneously for decoder activation. |
| 6 (E3) | Enable input (active HIGH) | Inverts enable polarity; used with E1/E2 to form 3-input AND gate controlling all outputs. |
| 7 (Y0) | Output (active LOW) | First decoded output; goes LOW only when A2A1A0 = 000 and all enables satisfied; open-drain compatible. |
| 8 (GND) | Ground reference | 0 V return path for all internal circuitry and output loads; requires low-impedance PCB connection. |
| 9 (Y1) | Output (active LOW) | Second decoded output; activates on A2A1A0 = 001; shares same timing and drive strength as Y0–Y7. |
| 10 (Y2) | Output (active LOW) | Third decoded output; activates on A2A1A0 = 010; identical electrical characteristics across all eight outputs. |
| 11 (Y3) | Output (active LOW) | Fourth decoded output; activates on A2A1A0 = 011; supports demultiplexing when E1/E2 used as data/strobe. |
| 12 (Y4) | Output (active LOW) | Fifth decoded output; activates on A2A1A0 = 100; enables 1-of-32 expansion with four devices and one inverter. |
| 13 (Y5) | Output (active LOW) | Sixth decoded output; activates on A2A1A0 = 101; maintains mutual exclusivity with all other Yx outputs. |
| 14 (Y6) | Output (active LOW) | Seventh decoded output; activates on A2A1A0 = 110; designed for low skew between outputs (balanced delays). |
| 15 (Y7) | Output (active LOW) | Eighth decoded output; activates on A2A1A0 = 111; guaranteed HIGH when disabled-no floating state. |
| 16 (VCC) | Supply voltage | +4.5 V to +5.5 V DC supply; bypass capacitor (100 nF ceramic) required within 10 mm of pin for noise suppression. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Accepts standard 5 V TTL logic levels (VIH ≥ 2.0 V, VIL ≤ 0.8 V), eliminating need for level translators in legacy 5 V systems. |
| Inverting active-low outputs | Eight mutually exclusive Y0–Y7 outputs drive LOW when selected, simplifying interface with enable-active-low peripherals like SRAM or flash chips. |
| Three-input enable logic | E1 (LOW), E2 (LOW), E3 (HIGH) form a 3-input AND gate-enabling hierarchical decoding and easy cascading to larger address spaces. |
| Automotive qualification | AEC-Q100 Grade 1 certified (-40 °C to +125 °C), including HTOL, temperature cycling, and ESD stress per JS-001/JS-002. |
| Low dynamic power | CPD = 23.0 pF enables predictable switching power calculation, critical for thermal management in compact automotive ECUs. |
Applications
| Engine Control Unit (ECU) Memory Decoding | ADAS Camera Interface Multiplexing |
|---|---|
|
Use Scenario: Selecting among multiple SRAM or EEPROM chips in a multi-core ECU using shared address/data bus. IC Role / Device Role / Timing Role: Address decoder mapping 3-bit chip select lines to eight independent memory banks with sub-10 ns propagation delay. Use Value: Eliminates discrete logic gates; reduces BOM count and layout area while ensuring deterministic timing across temperature extremes. |
Use Scenario: Routing serialized camera sensor data streams (e.g., MIPI CSI-2 lanes) to different image processing cores. IC Role / Device Role / Timing Role: Demultiplexer using E1 as data input and A0–A2 as channel select, enabling 1-to-8 lane distribution. Use Value: Provides glitch-free channel selection with Schmitt-trigger inputs rejecting noise from high-speed sensor interfaces. |
| Infotainment System Peripheral Expansion | Electric Power Steering (EPS) Fault Monitoring |
|
Use Scenario: Expanding GPIO count from a low-pin-count MCU to drive LED indicators, buttons, and CAN transceivers. IC Role / Device Role / Timing Role: Decoder enabling 8 peripheral enables from 3 MCU pins, with E3 tied HIGH and E1/E2 used for bank selection. Use Value: Reduces MCU pin utilization by 5:1 ratio while maintaining full software control over individual peripheral activation. |
Use Scenario: Monitoring 8 independent motor phase current sensors in EPS module and routing fault signals to safety controller. IC Role / Device Role / Timing Role: Active-low output decoder asserting dedicated fault lines (Y0–Y7) to ISO 26262-compliant monitoring logic. Use Value: Delivers fail-safe signal routing with AEC-Q100 qualification and guaranteed HIGH-state outputs during disable conditions. |
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 |
|---|---|---|---|
| 74AHC138D-Q100 | CMOS-input version; VIH ≥ 3.85 V at VCC = 5.5 V; lower ICC (4 μA typ) but incompatible with TTL logic sources. | Requires CMOS-level drivers; unsuitable for direct replacement in legacy 5 V TTL systems without level translation. | Select when interfacing with 3.3 V or 5 V CMOS microcontrollers and lowest static power is critical. |
| SN74LS138DR | Legacy LSTTL; higher ICC (48 mA max), slower tpd (22 ns typ), no AEC-Q100 qualification, -40 °C to +85 °C only. | Limited to non-automotive industrial or consumer applications; incompatible with 125 °C under-hood environments. | Use only for cost-sensitive, non-automotive designs where qualification and extended temperature are not required. |
Compared with 74AHC138D-Q100 and SN74LS138DR, the 74AHCT138D-Q100 uniquely bridges TTL logic compatibility, AEC-Q100 Grade 1 qualification, and sub-5 ns propagation delay-making it the sole fit for new automotive designs requiring drop-in TTL interoperability and full temperature range support.
Availability
74AHCT138D-Q100 is available at Aetrix Electronics and suitable for automotive engine control units, ADAS camera interfaces, infotainment peripheral expansion, and electric power steering fault monitoring requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 74AHCT138D-Q100 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 specializing in high-performance, high-reliability logic, analog, and discrete components, with leadership in automotive-qualified silicon.
The 74AHCT138D-Q100 belongs to Nexperia's automotive logic portfolio, engineered specifically for robust address decoding and signal routing in safety-critical vehicle subsystems operating from -40 °C to +125 °C.
FAQ
Can 74AHCT138D-Q100 operate at 3.3 V supply?
No. The 74AHCT138D-Q100 is TTL-compatible and specified only for VCC = 4.5 V to 5.5 V. At 3.3 V, input thresholds (VIH ≥ 2.0 V) may be met, but VOH and VOL performance, propagation delay, and AEC-Q100 compliance are not guaranteed. Use 74AHC138D-Q100 for 3.3 V systems.
What is the maximum capacitive load supported on Y0–Y7 outputs?
The outputs are characterized up to CL = 50 pF in dynamic specifications, with tpd tested at both 15 pF and 50 pF. Driving loads > 50 pF increases propagation delay nonlinearly and may cause ringing; add series termination or buffer stages for heavier loads.
How should unused enable inputs be terminated?
Unused enable inputs must be permanently tied to their active state: E1 and E2 to GND (active LOW), E3 to VCC (active HIGH). Floating enables risk metastability, increased ICC, and unintended output activation due to noise coupling.
Does 74AHCT138D-Q100 support hot insertion or live swapping?
No. The device lacks hot-swap protection features such as power-on reset, Ioff, or back-drive immunity. Applying VCC before or after signal inputs may cause latch-up or excessive ICC. Power sequencing per manufacturer guidelines is mandatory.
74AHCT138D-Q100J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- 74AHCT
- Package/Case:
- 16-SOIC (0.154", 3.90mm 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:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
74AHCT138D-Q100J FAQ
1.How can I place an order for 74AHCT138D-Q100J through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AHCT138D-Q100J 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 74AHCT138D-Q100J reliable?
The price and inventory of 74AHCT138D-Q100J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AHCT138D-Q100J is usually 5 days.
3.What payment methods are accepted for 74AHCT138D-Q100J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AHCT138D-Q100J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74AHCT138D-Q100J?
74AHCT138D-Q100J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AHCT138D-Q100J 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 74AHCT138D-Q100J?
For technical support, including 74AHCT138D-Q100J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AHCT138D-Q100J requirements.
6.How does Aetrix verify that 74AHCT138D-Q100J is sourced from the original manufacturer or authorized distributors?
All 74AHCT138D-Q100J 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 74AHCT138D-Q100J meets industry standards.
7.What is the process for return or replacement of 74AHCT138D-Q100J?
All 74AHCT138D-Q100J units undergo pre-shipment inspection (PSI). If there is an issue with 74AHCT138D-Q100J, 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 74AHCT138D-Q100J part is unused and in its original packaging.
Return procedure for 74AHCT138D-Q100J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
74AHCT138D-Q100J Tags
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SN74HC138DR
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