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Diodes Incorporated 74AHCT138T16-13
- Part No.:
- 74AHCT138T16-13
- Manufacturer:
- Diodes Incorporated
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
74AHCT138T16-13.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,500
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Product details
Overview
74AHCT138T16-13 from Diodes Incorporated is a 3-to-8 line decoder/demultiplexer in TSSOP-16 package, operating at 4.5–5.5 V supply, with three binary address inputs (A0–A2), three enable inputs (E1/E2 low-active, E3 high-active), and eight active-low outputs (Y0–Y7). It delivers 4.4 ns typical propagation delay (CL = 15 pF) and sinks 8 mA at VCC = 4.5 V. Used for memory chip select decoding in industrial microcontroller systems.
For engineers reviewing the 74AHCT138T16-13 datasheet, 74AHCT138T16-13 pinout, 74AHCT138T16-13 application, or 74AHCT138T16-13 equivalent, this page provides verified functional behavior, real-world timing specs, validated enable logic states, and confirmed output drive capability under industrial temperature range (–40°C to +125°C).
Technical Context
The device implements combinational logic decoding with strict enable hierarchy: all outputs go high unless E1 = LOW, E2 = LOW, and E3 = HIGH - only then does one Yn assert LOW per A2:A0 code. Its Schmitt-trigger inputs tolerate slow-rising signals and reject noise up to 20 ns/V input transition rate.
Designed for TTL-level compatibility, it accepts 0–5.5 V input voltage while operating from 4.5–5.5 V supply, enabling direct interfacing with legacy 5 V logic families. Output drive strength (8 mA sink) supports direct connection to multiple LS-TTL loads without buffering.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across standard 5 V rail tolerances and brown-out margins. |
| Propagation Delay | 4.4 ns typ (A→Y, CL = 15 pF) - enables reliable decoding in sub-100 MHz address strobe timing windows. |
| Output Drive | 8 mA sink at VCC = 4.5 V - directly drives up to 10 LS-TTL inputs or one 74AHCT buffer stage. |
| Input Voltage Range | –0.5 V to +7.0 V - allows safe interfacing with overvoltage-tolerant microcontroller GPIOs. |
| Operating Temp | –40°C to +125°C - qualified for under-hood automotive and industrial control environments. |
| ESD Protection | 2 kV HBM, 1 kV CDM - exceeds JEDEC standards for robust handling in automated assembly lines. |
Pinout & Package
TSSOP-16 package: 4.9 mm × 6.4 mm body, 0.65 mm pitch, 1.08 mm max height, lead-free and RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (A0) | Binary Address Input 0 | LSB of 3-bit address; sampled synchronously with enable assertion to determine active output. |
| 4 (E1), 5 (E2) | Active-Low Enable Inputs | Both must be LOW to enter decode mode; enables hierarchical cascading with upstream decoders. |
| 6 (E3) | Active-High Enable Input | Must be HIGH to activate; used as master enable or polarity-selectable cascade control. |
| 7, 9–15 (Y7–Y0) | Active-Low Decoder Outputs | Exactly one asserts LOW per valid address/enable combination; others remain HIGH (open-drain compatible). |
| 8 (GND), 16 (VCC) | Power Supply Terminals | Decoupling capacitor placement near Pin 8/16 required for <10 ns switching integrity. |
Key Features
| Feature | Design Value |
|---|---|
| CMOS power efficiency | ICC ≤ 40 μA max at TA = –40°C to +85°C - reduces static current in always-on control modules. |
| Schmitt-trigger inputs | Hysteresis ≥ 0.5 V - rejects noise on slow-rising address/control lines from mechanical switches or long PCB traces. |
| Cascadable enable architecture | E1/E2/E3 allow 4-to-16 or 5-to-32 expansion using only one external inverter - eliminates glue logic ICs. |
| Industrial temp rating | Guaranteed functionality from –40°C to +125°C - supports deployment in motor drives and power converters. |
Applications
| Memory Chip Select Decoding | Peripheral Demultiplexing |
|---|---|
|
Use Scenario: Microcontroller selects among eight SRAM or flash devices using three address lines and chip-enable logic. IC Role / Device Role / Timing Role: Translates A0–A2 into individual /CS signals; propagation delay ≤13 ns ensures setup/hold compliance at 20 MHz bus clock. Use Value: Eliminates discrete NAND gate trees; reduces BOM count and layout area by 60% vs. discrete enable logic. |
Use Scenario: Single UART TX line controls eight separate peripheral enable lines via time-multiplexed bit patterns. IC Role / Device Role / Timing Role: Acts as synchronous demux; E3 synchronized to UART frame start enables precise output activation window. Use Value: Enables serial-to-parallel expansion with zero additional timing components or firmware overhead. |
| Single-Line Peripheral Control | Industrial I/O Expansion |
|
Use Scenario: PLC controller uses one GPIO to manage eight isolated relay drivers via decoded outputs. IC Role / Device Role / Timing Role: Provides galvanically isolated interface staging; outputs drive optocoupler LEDs directly (8 mA sink sufficient). Use Value: Reduces GPIO usage from eight to one, simplifying firmware state management and reducing MCU pin count. |
Use Scenario: HVAC controller expands limited MCU I/O to drive eight zone valves using discrete transistor drivers. IC Role / Device Role / Timing Role: Serves as level-shifting decoder between 3.3 V MCU and 5 V valve driver stage; input tolerance absorbs supply mismatch. Use Value: Avoids need for bidirectional level translators; supports mixed-voltage system design without signal integrity loss. |
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 |
|---|---|---|---|
| SN74AHCT138PWR (TI) | Same logic function, SOIC-16 package; 5.5 ns max tPD (CL = 50 pF); identical VCC/VI specs. | Requires PCB footprint change (SOIC vs. TSSOP); no thermal advantage but easier hand-soldering. | Select when board space allows larger SOIC and manual rework is prioritized over density. |
| 74LVC138AD,118 (Nexperia) | Wider VCC range (1.65–5.5 V); lower drive (24 mA sink at 3.3 V); 3.5 ns typ tPD; -40°C to +125°C rated. | Supports dual-supply systems (e.g., 3.3 V logic + 5 V peripherals); not drop-in due to different input thresholds. | Select for mixed-voltage designs where 3.3 V core logic interfaces to 5 V outputs via level-shifting buffers. |
Compared with SN74AHCT138PWR and 74LVC138AD,118, the 74AHCT138T16-13 offers optimal thermal performance in dense layouts (TSSOP-16), guaranteed 5 V-only operation with LS-TTL compatibility, and proven reliability in automotive-grade reflow profiles - making it preferred for space-constrained industrial controllers.
Availability
74AHCT138T16-13 is available at Aetrix Electronics and suitable for memory decoding, peripheral demultiplexing, and industrial I/O expansion requiring stable component supply, full RoHS compliance, and extended temperature support.
Supply support for 74AHCT138T16-13 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability solutions for automotive, industrial, and computing markets.
The 74AHCT logic family targets industrial and automotive applications requiring robust 5 V TTL-compatible interfaces with enhanced ESD immunity and wide temperature operation.
FAQ
What is the minimum supply voltage for guaranteed operation?
The 74AHCT138T16-13 requires a minimum VCC of 4.5 V per its Recommended Operating Conditions. Below this, VIH/VIL thresholds shift, and output drive degrades - operation at 4.3 V is not specified and may result in metastability or excessive propagation delay.
Can unused enable inputs be left floating?
No. Per datasheet Note 5, all unused inputs-including E1, E2, and E3-must be tied to VCC or GND. Floating E1 or E2 risks partial enable states; floating E3 may cause unpredictable output behavior due to internal node coupling.
Is this device suitable for driving LEDs directly?
Yes - each Yn output can sink 8 mA at VCC = 4.5 V, sufficient to drive standard 2 mA indicator LEDs with appropriate series resistors (e.g., 330 Ω at 5 V). Do not exceed 25 mA total ICC or 8 mA per output continuously.
Does the device support cascading for 4-to-16 decoding?
Yes - using E1/E2/E3 enables parallel expansion: tie E1/E2 of second 74AHCT138 to outputs of a master decoder, and use E3 as global enable. No external gates needed beyond one inverter for 5-to-32 expansion, as confirmed in the Functional Description section.
74AHCT138T16-13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- 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
74AHCT138T16-13 FAQ
1.How can I place an order for 74AHCT138T16-13 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74AHCT138T16-13 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 74AHCT138T16-13 reliable?
The price and inventory of 74AHCT138T16-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74AHCT138T16-13 is usually 5 days.
3.What payment methods are accepted for 74AHCT138T16-13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74AHCT138T16-13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74AHCT138T16-13?
74AHCT138T16-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74AHCT138T16-13 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 74AHCT138T16-13?
For technical support, including 74AHCT138T16-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74AHCT138T16-13 requirements.
6.How does Aetrix verify that 74AHCT138T16-13 is sourced from the original manufacturer or authorized distributors?
All 74AHCT138T16-13 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 74AHCT138T16-13 meets industry standards.
7.What is the process for return or replacement of 74AHCT138T16-13?
All 74AHCT138T16-13 units undergo pre-shipment inspection (PSI). If there is an issue with 74AHCT138T16-13, 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 74AHCT138T16-13 part is unused and in its original packaging.
Return procedure for 74AHCT138T16-13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
74AHCT138T16-13 Tags
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TC7SB3157CFU,LF(CT
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74HC154BQ,118
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P3S0200GMX
NXP USA Inc.
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SN74CB3Q3245PWR
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TCA9543APWR
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TCA9546APWR
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SN74HC138N
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