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Texas Instruments SN74AC138WBQBRQ1
- Part No.:
- SN74AC138WBQBRQ1
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
SN74AC138WBQBRQ1.pdf
- Description:
- Automotive 3-Line to 8-Line
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
SN74AC138WBQBRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive 3-line-to-8-line decoder/demultiplexer with three enable inputs (G2, G̅1, G̅0), 16-pin WQFN wettable flank package, 1.5V–6V supply range, and 10.2ns max propagation delay at 5V/50pF. It drives memory chip select lines in engine control units requiring precise address decoding under harsh thermal conditions.
For engineers reviewing the SN74AC138WBQBRQ1 datasheet, SN74AC138WBQBRQ1 pinout, SN74AC138WBQBRQ1 application, or SN74AC138WBQBRQ1 equivalent, key selection criteria include automotive-grade ESD robustness (HBM ±2kV, CDM ±1kV), output drive capability (±24mA continuous, ±75mA burst), and dual-package compatibility (TSSOP PW and WQFN BQB) for layout flexibility in safety-critical ECUs.
Technical Context
The SN74AC138WBQBRQ1 implements a positive-logic 3-to-8 decoder with three independent strobe inputs: one active-high (G2) and two active-low (G̅1, G̅0). When any strobe disables the device, all eight outputs (Y0–Y7) are forced high; only the selected output goes low when strobes permit decoding.
Its balanced CMOS push-pull outputs support direct 50Ω transmission line driving and tolerate input voltages up to 6V regardless of VCC level. The device operates across -40°C to +125°C ambient, with thermal metrics optimized for WQFN (RθJA = 98.8°C/W) and TSSOP (RθJA = 141.8°C/W) packages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.5V to 6V - supports single-rail operation across 1.8V, 2.5V, 3.3V, and 5V logic domains without level shifters |
| Propagation Delay (tpd) | 10.2ns max at 5V/50pF - enables sub-100MHz address decoding in real-time engine timing systems |
| Output Drive (Continuous) | ±24mA at 5V - sufficient to directly drive multiple CMOS inputs or small-signal MOSFET gates |
| Output Drive (Burst) | ±75mA at 5V for ≤2ms - allows short-duration signal routing or bus contention handling |
| Ambient Temperature Range | -40°C to +125°C - qualified per AEC-Q100 Grade 1 for under-hood automotive applications |
| ESD Rating (HBM) | ±2000V - meets automotive system-level ESD immunity requirements without external protection |
| Input Voltage Tolerance | 0V to VCC + 0.5V - accepts 5V-tolerant inputs even when powered from 1.8V or 2.5V rails |
Pinout & Package
SN74AC138WBQBRQ1 uses the BQB (16-pin WQFN) package with 3.5mm × 2.5mm body size and wettable flanks for automated optical inspection. Thermal pad is optional and may be connected to GND or left floating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0, A1, A2 | Address Select Inputs | Binary-coded 3-bit address determining which Yx output goes low; compatible with MCU GPIOs or FPGA I/O banks |
| G2 | Active-High Enable Strobe | Primary enable: device active only when G2 = HIGH; used for hierarchical decoding or power-gating control |
| G̅1, G̅0 | Active-Low Enable Strobes | Secondary enables: both must be LOW for decode operation; reduce need for external inverters in multi-chip select trees |
| Y0–Y7 | Active-Low Outputs | Eight decoded outputs; only one low at a time when enabled - ideal for selecting memory devices or peripheral ICs |
| VCC | Positive Supply | Single supply pin supporting 1.5V–6V; requires local 0.1µF bypass capacitor per TI layout guidelines |
| GND | Ground Reference | Common return path for all signals and supply current; must connect to solid ground plane for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for -40°C to +125°C operation in engine control modules, transmission controllers, and ADAS domain ECUs |
| Wettable flank QFN (BQB) | Enables reliable AOI solder-joint inspection on automotive PCBs without X-ray, reducing manufacturing defect escape |
| 50Ω transmission line drive | Supports point-to-point routing to memory or sensor interfaces without external termination resistors |
| Input voltage tolerance up to 6V | Eliminates level-shifting circuitry when interfacing with legacy 5V peripherals or industrial I/O subsystems |
| Balanced CMOS push-pull outputs | Provides symmetrical rise/fall times and matched sourcing/sinking capability for clean signal integrity in noisy environments |
Applications
| Engine Control Unit (ECU) Memory Decoding | Advanced Driver Assistance Systems (ADAS) Sensor Multiplexing |
|---|---|
Use Scenario: Selecting among multiple flash memory banks or EEPROM 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 transitions. Use Value: Reduces MCU GPIO count by 5 pins versus discrete logic; enables deterministic <10.2ns address setup/hold timing under 125°C ambient. |
Use Scenario: Routing camera or radar sensor data streams to different processing paths based on vehicle mode (e.g., parking vs highway). IC Role / Device Role / Timing Role: Demultiplexer using G2 as data input and A2–A0 as channel select, enabling time-division signal routing. Use Value: Supports burst-mode sensor data handoff with ±75mA peak drive for transient loading during frame sync pulses. |
| Body Control Module (BCM) Peripheral Selection | Electric Power Steering (EPS) Motor Driver Interface |
Use Scenario: Managing up to eight LIN transceivers, LED drivers, or window motor controllers from a single microcontroller port. IC Role / Device Role / Timing Role: Address decoder translating 3-bit port outputs into individual enable signals for distributed peripherals. Use Value: Eliminates need for external inverters due to dual active-low enables (G̅1, G̅0), simplifying PCB layout in space-constrained BCMs. |
Use Scenario: Enabling specific half-bridge gate drivers or current-sense amplifiers within an EPS motor control ASIC interface. IC Role / Device Role / Timing Role: Safety-critical decoder gating driver enable lines in response to ASIL-B fault detection signals. Use Value: AEC-Q100 qualification ensures functional reliability during motor stall events where junction temperature exceeds 130°C. |
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 |
|---|---|---|---|
| SN74LV138A-Q1 | Lower supply range (1.65V–5.5V); slower max tpd (17.5ns at 3.3V); ±12mA continuous drive | Better suited for low-power body electronics; insufficient for high-speed ECU memory decoding | Select when operating below 1.8V or prioritizing static current (<1µA) over speed |
| 74AC138SCX | Commercial grade (-40°C to +85°C); no AEC-Q100 qualification; same pinout and electrical specs | Acceptable for non-automotive industrial controls but not certified for automotive safety-critical use | Choose only for cost-sensitive non-automotive designs where automotive qualification is unnecessary |
Compared with SN74LV138A-Q1 and 74AC138SCX, SN74AC138WBQBRQ1 uniquely delivers Grade 1 thermal performance, wettable flank inspection capability, and ±75mA burst drive-making it the sole option qualified for ASIL-B–related decoding in powertrain and chassis systems.
Availability
SN74AC138WBQBRQ1 is available at Aetrix Electronics and suitable for engine control units, ADAS sensor hubs, and electric power steering modules requiring stable component supply across extended automotive lifecycles.
Supply support for SN74AC138WBQBRQ1 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 leader specializing in analog, embedded processing, and automotive ICs, with decades of experience delivering AEC-Q100–qualified components for safety-critical vehicle systems.
The SN74AC138WBQBRQ1 belongs to TI's automotive logic portfolio designed specifically for robust address decoding and signal routing in powertrain, chassis, and ADAS electronic control units operating under extreme thermal and EMI conditions.
FAQ
What is the maximum operating temperature for SN74AC138WBQBRQ1?
The SN74AC138WBQBRQ1 is rated for operation from -40°C to +125°C ambient temperature and is qualified per AEC-Q100 Grade 1. This specification applies to the full device functionality including propagation delay, output drive, and enable logic behavior - verified across temperature and voltage corners in TI's automotive qualification testing. The SN74AC138WBQBRQ1 maintains guaranteed timing and drive strength throughout this range.
Does SN74AC138WBQBRQ1 support 1.8V logic levels?
Yes, SN74AC138WBQBRQ1 fully supports 1.8V operation with guaranteed parameters: VIH = 1.26V min, VIL = 0.54V max, and tpd = 28.5ns max at 1.8V/50pF. Its wide 1.5V–6V supply range allows direct interface with 1.8V microcontrollers without level translation, while maintaining AEC-Q100 compliance across the entire voltage and temperature envelope.
Can SN74AC138WBQBRQ1 drive a 50Ω transmission line directly?
Yes, SN74AC138WBQBRQ1 is explicitly characterized to drive 50Ω transmission lines, as confirmed in its Features section and Switching Characteristics table. At 5V supply, its balanced CMOS outputs deliver clean edges into 50Ω loads without external series termination, supporting point-to-point routing in high-speed automotive data paths such as sensor interface backplanes.
What is the purpose of the thermal pad on the SN74AC138WBQBRQ1 WQFN package?
The thermal pad on the SN74AC138WBQBRQ1 (BQB package) may be connected to GND or left floating - it is not required for thermal performance but improves solder joint reliability and provides additional grounding for noise suppression. TI's datasheet states "Do not connect to any other signal or supply," and the pad has no internal electrical connection beyond mechanical attachment.
How does the enable logic work on SN74AC138WBQBRQ1?
SN74AC138WBQBRQ1 uses three independent enable inputs: G2 (active-high), G̅1 (active-low), and G̅0 (active-low). All three must be asserted simultaneously (G2 = HIGH, G̅1 = LOW, G̅0 = LOW) for decoding to occur; if any enable is inactive, all eight outputs (Y0–Y7) go high-impedance equivalent (forced HIGH). This architecture minimizes external logic for hierarchical chip select trees in automotive memory subsystems.
SN74AC138WBQBRQ1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- 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:
- 1.5V ~ 6V
- 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)
SN74AC138WBQBRQ1 FAQ
1.How can I place an order for SN74AC138WBQBRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC138WBQBRQ1 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 SN74AC138WBQBRQ1 reliable?
The price and inventory of SN74AC138WBQBRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC138WBQBRQ1 is usually 5 days.
3.What payment methods are accepted for SN74AC138WBQBRQ1?
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SN74AC138WBQBRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC138WBQBRQ1 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 SN74AC138WBQBRQ1?
For technical support, including SN74AC138WBQBRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC138WBQBRQ1 requirements.
6.How does Aetrix verify that SN74AC138WBQBRQ1 is sourced from the original manufacturer or authorized distributors?
All SN74AC138WBQBRQ1 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 SN74AC138WBQBRQ1 meets industry standards.
7.What is the process for return or replacement of SN74AC138WBQBRQ1?
All SN74AC138WBQBRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC138WBQBRQ1, 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 SN74AC138WBQBRQ1 part is unused and in its original packaging.
Return procedure for SN74AC138WBQBRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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