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Texas Instruments SN74ACT138WBQBRQ1
- Part No.:
- SN74ACT138WBQBRQ1
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
SN74ACT138WBQBRQ1.pdf
- Description:
- Automotive 3-Line to 8-Line
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
SN74ACT138WBQBRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive 3-line-to-8-line decoder/demultiplexer with TTL-compatible CMOS inputs, 4.5V–5.5V supply range, 10.2ns propagation delay (5V, 50pF), ±24mA continuous output drive, and wettable-flank WQFN-16 packaging for AOI-compatible solder joint inspection. It enables memory device selection and chip-select signal routing in engine control units and ADAS domain controllers.
For engineers reviewing the SN74ACT138WBQBRQ1 datasheet, SN74ACT138WBQBRQ1 pinout, SN74ACT138WBQBRQ1 application, or SN74ACT138WBQBRQ1 equivalent, key selection criteria include automotive-grade temperature range (-40°C to +125°C), dual active-low plus one active-high enable architecture, balanced push-pull output capability, TTL-level input compatibility, and wettable-flank QFN package for production traceability and reliability validation.
Technical Context
The SN74ACT138WBQBRQ1 implements a positive-logic 3-to-8 decoder with three binary address inputs (A0–A2), two active-low strobes (G̅₀, G̅₁), and one active-high strobe (G₂). All eight outputs (Y₀–Y₇) are active-low and mutually exclusive: only one output goes low when enabled and addressed, while all others remain high.
Its TTL-compatible inputs accept logic thresholds as low as 2V VIH and 0.8V VIL, enabling direct interfacing with legacy 5V TTL systems without level-shifting. The balanced CMOS push-pull outputs support both sourcing and sinking up to ±24mA continuously, with short-burst capability up to ±75mA - critical for driving transmission lines and multiple CMOS loads in safety-critical automotive subsystems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - ensures stable operation across automotive battery rail variations including cold-crank (4.5V) and load-dump (5.5V) conditions. |
| Propagation Delay | 10.2ns max (5V, CL = 50pF) - enables timing-critical decoding in real-time control loops with sub-100ns budget margins. |
| Output Drive | ±24mA continuous - sufficient to directly drive 50Ω transmission lines or fan-out to ≥10 standard CMOS loads at 5V. |
| Operating Temperature | -40°C to +125°C (Grade 1) - qualified for under-hood and powertrain applications per AEC-Q100 requirements. |
| Input Compatibility | TTL-compatible (VIH = 2V min, VIL = 0.8V max) - eliminates need for external level shifters when interfacing with legacy microcontrollers or discrete logic. |
| ESD Rating | HBM ±2000V, CDM ±1000V - meets automotive ESD robustness requirements for assembly and field operation. |
| Package | WQFN-16 (BQB), 3.5mm × 2.5mm with wettable flanks - supports automated optical inspection (AOI) of solder joints and high-density PCB layouts. |
Pinout & Package
SN74ACT138WBQBRQ1 uses the BQB package: 16-pin wettable-flank WQFN, 3.5mm × 2.5mm body size, thermal pad exposed on bottom (recommended to connect to GND for thermal and EMI performance).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0, A1, A2 | Binary address inputs | Select one of eight outputs (Y₀–Y₇); decoded in positive logic with active-low outputs. |
| G̅₀, G̅₁ | Active-low enable strobes | Both must be LOW and G₂ HIGH for decoder to operate; enables hierarchical expansion without external inverters. |
| G₂ | Active-high enable strobe | Used as data input in demultiplexing mode; allows single-input-to-eight-output signal routing. |
| Y₀–Y₇ | Active-low decoded outputs | Only one output asserts LOW per valid address/enable combination; all others remain HIGH. |
| VCC | Positive supply | Must be decoupled with 0.1μF capacitor placed adjacent to pin; supports 4.5V–5.5V automotive rail. |
| GND | Ground reference | Return path for all I/O and supply currents; thermal pad connection improves thermal resistance by 46.2°C/W. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for -40°C to +125°C operation with full electrical testing across temperature, ensuring reliability in engine control modules and radar ECUs. |
| Wettable-flank WQFN package | Enables automated optical inspection (AOI) of side-solder fillets, improving manufacturing yield and field failure traceability in automotive production. |
| Balanced push-pull outputs | Sinks and sources equal current (±24mA), allowing bidirectional signal routing and compatibility with both pull-up and pull-down load configurations. |
| TTL-compatible CMOS inputs | Accepts 2V VIH and 0.8V VIL thresholds - interoperable with legacy 5V TTL logic without level translation, reducing BOM count and board space. |
| Three-strobe enable architecture | Two active-low (G̅₀, G̅₁) and one active-high (G₂) enables flexible cascading: 24-line decoder possible without external inverters; 32-line requires only one inverter. |
Applications
| Engine Control Unit (ECU) Memory Selection | ADAS Domain Controller Chip Select |
|---|---|
Use Scenario: Selecting among multiple flash or SRAM devices sharing a common data bus in a gasoline/diesel ECU. IC Role / Device Role / Timing Role: 3-to-8 decoder providing chip-select signals synchronized to MCU address bus and clock domain. Use Value: Reduces MCU GPIO usage by consolidating eight discrete chip-select lines into three address pins and three strobes, simplifying firmware and PCB routing. | Use Scenario: Managing peripheral access (camera ISPs, radar processors, CAN transceivers) in centralized ADAS domain controllers. IC Role / Device Role / Timing Role: Demultiplexer routing configuration commands from central processor to targeted sensor interface ICs. Use Value: Enables deterministic, low-latency peripheral enable sequencing with <10.2ns propagation delay - critical for time-synchronized sensor fusion. |
| Automotive Instrument Cluster Display Driver | Body Control Module (BCM) I/O Expansion |
Use Scenario: Driving segment or LED backlight enable lines in digital instrument clusters with multi-zone dimming. IC Role / Device Role / Timing Role: Active-low output decoder selecting display driver ICs or LED strings based on CAN message payload. Use Value: Delivers ±24mA per output to directly drive LED strings or gate drivers without external transistors, reducing component count and thermal footprint. | Use Scenario: Expanding limited MCU GPIOs to manage door lock actuators, window motors, and lighting relays in modern BCMs. IC Role / Device Role / Timing Role: Addressable enable generator converting serial command bits into parallel relay control signals. Use Value: Supports fail-safe operation via independent strobe gating: any fault on G̅₀, G̅₁, or G₂ forces all outputs HIGH, de-energizing connected loads. |
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 |
|---|---|---|---|
| SN74LV138AQPWRQ1 | Lower voltage range (2V–5.5V), slower propagation (15.5ns), LV-CMOS inputs (not TTL-compatible) | Better suited for mixed-voltage domains with 3.3V MCUs; not drop-in for legacy 5V TTL interfaces | Select when system operates below 4.5V or prioritizes lower static power over speed and TTL compatibility. |
| MC74VHC138DTG | Non-automotive grade (industrial temp only), no AEC-Q100 qualification, same pinout but different package (TSSOP-16) | Lacks automotive qualification and wettable flank; suitable for non-safety-critical infotainment or test equipment | Choose only for cost-sensitive non-automotive designs where AEC-Q100 compliance and AOI support are unnecessary. |
Compared with SN74LV138AQPWRQ1 and MC74VHC138DTG, the SN74ACT138WBQBRQ1 uniquely combines AEC-Q100 Grade 1 qualification, TTL-compatible inputs, wettable-flank WQFN packaging, and 10.2ns speed - making it the sole option for timing-critical, legacy-interface automotive decoding requiring production traceability and AOI validation.
Availability
SN74ACT138WBQBRQ1 is available at Aetrix Electronics and suitable for engine control units, ADAS domain controllers, and body control modules requiring stable component supply across extended automotive temperature ranges and long production lifecycles.
Supply support for SN74ACT138WBQBRQ1 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 company specializing in analog and embedded processing technologies, with leadership in automotive, industrial, and power management solutions.
The SN74ACT138WBQBRQ1 belongs to TI's automotive logic portfolio, designed specifically to replace legacy TTL decoders in safety-critical vehicle subsystems while meeting AEC-Q100 reliability, thermal, and manufacturability requirements.
FAQ
What is the maximum operating temperature for the SN74ACT138WBQBRQ1?
The SN74ACT138WBQBRQ1 is rated for operation from -40°C to +125°C (AEC-Q100 Grade 1), validated across this full range for junction temperature stability, propagation delay consistency, and output drive capability - essential for under-hood and powertrain applications where ambient temperatures exceed 105°C.
Does the SN74ACT138WBQBRQ1 support 3.3V logic inputs?
No - the SN74ACT138WBQBRQ1 features TTL-compatible CMOS inputs with VIH(min) = 2.0V and VIL(max) = 0.8V, optimized for 5V systems. While 3.3V logic may register as HIGH in some cases, it violates the recommended operating condition and risks marginal switching, increased power consumption, or oscillation; use SN74LV138AQPWRQ1 for guaranteed 3.3V compatibility.
Can the SN74ACT138WBQBRQ1 drive 50Ω transmission lines directly?
Yes - the SN74ACT138WBQBRQ1 is explicitly characterized to drive 50Ω transmission lines, supported by its ±24mA continuous output drive and fast edge rates. For optimal signal integrity, use series source termination near the output and maintain trace lengths ≤12cm per layout guidelines in the datasheet.
Is the thermal pad on the SN74ACT138WBQBRQ1 package required to be connected?
The thermal pad on the SN74ACT138WBQBRQ1 (BQB package) should be connected to GND for optimal thermal performance (RθJC(bot) = 46.2°C/W) and EMI suppression. Leaving it floating increases junction-to-board thermal resistance and may compromise long-term reliability in high-power-density automotive modules.
How many enable inputs does the SN74ACT138WBQBRQ1 have, and what are their logic polarities?
The SN74ACT138WBQBRQ1 has three enable inputs: G̅₀ and G̅₁ are active-low, and G₂ is active-high. All three must be asserted simultaneously (G̅₀ = L, G̅₁ = L, G₂ = H) for decoding to occur; any violation forces all Y₀–Y₇ outputs HIGH - a feature used for hierarchical expansion and fail-safe gating in automotive systems.
SN74ACT138WBQBRQ1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 3:8
- Independent Circuits:
- 1
- Current - Output High, Low:
- 24mA, 24mA
- 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, Wettable Flank
- Supplier Device Package:
- 16-WQFN (2.5x3.5)
SN74ACT138WBQBRQ1 FAQ
1.How can I place an order for SN74ACT138WBQBRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT138WBQBRQ1 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 SN74ACT138WBQBRQ1 reliable?
The price and inventory of SN74ACT138WBQBRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT138WBQBRQ1 is usually 5 days.
3.What payment methods are accepted for SN74ACT138WBQBRQ1?
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4.How is shipping managed for SN74ACT138WBQBRQ1?
SN74ACT138WBQBRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT138WBQBRQ1 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 SN74ACT138WBQBRQ1?
For technical support, including SN74ACT138WBQBRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT138WBQBRQ1 requirements.
6.How does Aetrix verify that SN74ACT138WBQBRQ1 is sourced from the original manufacturer or authorized distributors?
All SN74ACT138WBQBRQ1 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 SN74ACT138WBQBRQ1 meets industry standards.
7.What is the process for return or replacement of SN74ACT138WBQBRQ1?
All SN74ACT138WBQBRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT138WBQBRQ1, 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 SN74ACT138WBQBRQ1 part is unused and in its original packaging.
Return procedure for SN74ACT138WBQBRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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