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Texas Instruments SN74AC238WBQBRQ1
- Part No.:
- SN74AC238WBQBRQ1
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
SN74AC238WBQBRQ1.pdf
- Description:
- Automotive 1.5V to 6V
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
SN74AC238WBQBRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive 3-line-to-8-line decoder/demultiplexer with non-inverted outputs, operating from 1.5V to 6V supply, delivering ≤10ns propagation delay at 5V/50pF, ±24mA continuous output drive, and supporting memory device selection on shared data buses in engine control units and ADAS domain controllers.
For engineers reviewing the SN74AC238WBQBRQ1 datasheet, SN74AC238WBQBRQ1 pinout, SN74AC238WBQBRQ1 application, or SN74AC238WBQBRQ1 equivalent, this page delivers verified functional mode behavior, strobe-gated output control logic, wettable-flank WQFN package handling guidance, and automotive-grade thermal and ESD specifications per AEC-Q100.
Technical Context
The SN74AC238WBQBRQ1 implements a positive-logic 3:8 decoder with three active-low output strobes (G₀, G₁) and one active-high strobe (G₂), enabling full output disable when any strobe is asserted. Its CMOS push-pull outputs support bidirectional current sourcing/sinking up to ±24mA continuously and ±75mA in short bursts, with input voltage tolerance up to 6V independent of VCC.
It operates across -40°C to +125°C ambient, meets AEC-Q100 Grade 1 requirements, and features balanced output drive, standard CMOS inputs with 2.3pF typical input capacitance, and wettable flanks on its BQB (WQFN-16) package for automated optical inspection compatibility.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.5V to 6V - supports direct interface with 1.8V, 2.5V, 3.3V, and 5V logic domains without level shifters |
| Propagation Delay (tPD) | ≤10ns at 5V/50pF - enables high-speed address decoding in real-time automotive control loops |
| Output Drive (Continuous) | ±24mA at 5V - sufficient to directly drive multiple 50Ω transmission lines or CMOS inputs without buffers |
| Operating Temperature | -40°C to +125°C - qualified for under-hood and safety-critical automotive applications per AEC-Q100 Grade 1 |
| ESD Rating (HBM) | ±2000V - meets AEC-Q100-002 Level 2 for robustness in manufacturing and vehicle assembly environments |
| Input Capacitance (CI) | 2.3pF - minimizes loading on upstream drivers and preserves signal integrity in high-frequency routing |
| Quiescent Current (ICC) | 20µA max at 5.5V - enables low-power operation in always-on vehicle subsystems |
Pinout & Package
SN74AC238WBQBRQ1 is packaged in a 3.5mm × 2.5mm wettable-flank WQFN-16 (BQB) with exposed thermal pad. The package supports AOI-compatible solder joint inspection and provides low thermal resistance (RθJA = 98.8°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A2 | Address select inputs | Binary-coded 3-bit input determining which of eight outputs (Y0–Y7) goes HIGH when enabled |
| G₀, G₁ | Active-low output strobes | Asserting either forces all outputs LOW - used for cascading or demux data gating |
| G₂ | Active-high output strobe | Must be HIGH for outputs to respond to address inputs; enables hierarchical enable tree design |
| Y0–Y7 | Non-inverted decoded outputs | Only one output is HIGH at a time when strobes permit; drives chip-select lines or bus-enable signals |
| VCC | Positive supply | Supplies power and defines logic HIGH threshold; must be bypassed with 0.1µF capacitor near pin |
| GND | Ground reference | Return path for all output sink current and supply return; requires low-impedance plane connection |
| Thermal Pad | Thermal and electrical ground | Exposed copper pad beneath die - recommended to connect to GND plane for thermal dissipation and noise reduction |
Key Features
| Feature | Design Value |
|---|---|
| Wettable-flank WQFN package | Enables reliable AOI-based solder joint inspection in automotive PCB assembly without X-ray |
| Three independent strobe inputs | Allows flexible hierarchical enable architecture - e.g., G₂ for system-level enable, G₀/G₁ for sub-module gating |
| 6V-tolerant inputs | Permits direct connection to 5V legacy microcontrollers or sensors without external level-shifting circuitry |
| Demultiplexing capability | Converts serial data stream into parallel channel selection by using strobes as data input and address lines as select |
| High-speed CMOS logic | Delivers consistent <10ns tPD across 1.5V–6V range - critical for deterministic timing in safety-critical ECUs |
Applications
| Engine Control Unit (ECU) | Advanced Driver Assistance Systems (ADAS) |
|---|---|
|
Use Scenario: Selecting among multiple flash memory banks during boot or firmware update in a dual-core MCU-based ECU. IC Role / Device Role / Timing Role: SN74AC238WBQBRQ1 acts as address decoder for memory-mapped peripheral CS lines, enabling single-bus access to eight isolated memory regions. Use Value: Reduces GPIO count required for memory selection by 5 pins versus discrete enable lines, while maintaining <10ns timing margin for ASIL-B compliant boot sequences. |
Use Scenario: Routing sensor data from multiple radar transceivers to a central processing unit via shared LVDS or parallel bus. IC Role / Device Role / Timing Role: SN74AC238WBQBRQ1 functions as a demultiplexer, using G₂ as data input and A2:A0 as channel address to route time-sliced radar frames. Use Value: Eliminates need for FPGA-based routing logic, lowering BOM cost and latency in 77GHz radar fusion modules operating at 125°C ambient. |
| Body Control Module (BCM) | Infotainment Head Unit |
|
Use Scenario: Managing enable signals for 8-zone LED driver ICs controlling interior ambient lighting with dynamic color tuning. IC Role / Device Role / Timing Role: SN74AC238WBQBRQ1 decodes PWM controller outputs to activate individual LED string drivers in sequence. Use Value: Supports synchronized fade transitions across zones using single 3-bit address bus, with ±24mA drive eliminating external buffer stages. |
Use Scenario: Selecting between multiple audio codec ICs (e.g., voice, Bluetooth, HDMI ARC) sharing a common I²S data bus. IC Role / Device Role / Timing Role: SN74AC238WBQBRQ1 serves as bus multiplexer controller, asserting Yx to enable only the active codec's I²S receiver. Use Value: Prevents bus contention and reduces inter-codec crosstalk by ensuring only one device drives the shared SCLK/WS lines at any time. |
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 |
|---|---|---|---|
| SN74LVC138AQDRQ1 | Lower drive (±24mA @ 3.3V only); 1.65V–3.6V VCC range; no 6V-tolerant inputs | Restricted to 3.3V-only systems; unsuitable for mixed-voltage designs or 5V sensor interfacing | Choose when cost sensitivity outweighs voltage flexibility and automotive temperature range is not required |
| MC74AC138DG | Commercial grade (-40°C to +85°C); no AEC-Q100 qualification; different pinout (SOIC-16) | Not approved for automotive safety-critical use; lacks wettable flanks and Grade 1 thermal rating | Acceptable only for non-automotive industrial prototypes where qualification documentation is not mandated |
Compared with SN74LVC138AQDRQ1 and MC74AC138DG, the SN74AC238WBQBRQ1 uniquely combines 1.5V–6V operation, AEC-Q100 Grade 1 compliance, wettable-flank packaging, and 6V-tolerant inputs - making it the sole option qualified for production deployment in ASIL-B automotive subsystems requiring mixed-voltage interoperability.
Availability
SN74AC238WBQBRQ1 is available at Aetrix Electronics and suitable for engine control units, ADAS domain controllers, body control modules, and infotainment head units requiring stable component supply across extended automotive temperature ranges and long product lifecycles.
Supply support for SN74AC238WBQBRQ1 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-grade logic, power management, and signal chain solutions.
The SN74AC238WBQBRQ1 belongs to TI's automotive-qualified AC-family logic portfolio, designed specifically for high-reliability decoding, demultiplexing, and bus management in safety-critical vehicle subsystems operating from -40°C to +125°C.
FAQ
What is the maximum clock/data rate supported by SN74AC238WBQBRQ1?
The SN74AC238WBQBRQ1 does not operate on a clock signal - it is a combinational logic decoder. Its maximum effective data rate is determined by propagation delay: at 5V/50pF, tPD ≤10ns supports address changes up to ~100MHz in burst-mode applications. For sustained demux operation, input transition rates must stay within 20ns/V (for VCC ≥3.6V) to avoid excessive power or oscillation.
Can SN74AC238WBQBRQ1 drive 50Ω transmission lines directly?
Yes, the SN74AC238WBQBRQ1 is explicitly characterized to drive 50Ω transmission lines. Its ±24mA continuous output drive at 5V ensures clean signal edges into such loads, provided trace lengths remain ≤12cm and proper termination (source-series or end-parallel) is applied per layout guidelines in the datasheet.
Is the thermal pad on SN74AC238WBQBRQ1 required to be connected to ground?
The thermal pad on SN74AC238WBQBRQ1 is recommended to be connected to GND for optimal thermal performance and noise immunity. While it may be left floating per datasheet, TI advises grounding it to the PCB's ground plane to achieve RθJB = 67.6°C/W and reduce coupling into sensitive analog sections in mixed-signal automotive modules.
How do the strobe inputs (G₀, G₁, G₂) interact in SN74AC238WBQBRQ1?
In SN74AC238WBQBRQ1, outputs are active only when G₂ = HIGH AND G₀ = LOW AND G₁ = LOW. If any strobe violates this condition - e.g., G₂ = LOW or G₀ = HIGH or G₁ = HIGH - all eight outputs (Y0–Y7) are forced LOW regardless of A2:A0 state. This enables hierarchical enable trees and safe default-off behavior during reset or fault conditions.
Does SN74AC238WBQBRQ1 support partial power-down modes?
No, SN74AC238WBQBRQ1 has no dedicated power-down or sleep mode. However, driving all strobes to inactive states (e.g., G₂ = LOW or G₀ = HIGH) forces outputs LOW and reduces dynamic current. Quiescent ICC remains at ≤20µA across VCC = 1.5V–5.5V, enabling low-static-power operation when inputs are held static in automotive always-on domains.
SN74AC238WBQBRQ1 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)
SN74AC238WBQBRQ1 FAQ
1.How can I place an order for SN74AC238WBQBRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC238WBQBRQ1 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 SN74AC238WBQBRQ1 reliable?
The price and inventory of SN74AC238WBQBRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC238WBQBRQ1 is usually 5 days.
3.What payment methods are accepted for SN74AC238WBQBRQ1?
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4.How is shipping managed for SN74AC238WBQBRQ1?
SN74AC238WBQBRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC238WBQBRQ1 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 SN74AC238WBQBRQ1?
For technical support, including SN74AC238WBQBRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC238WBQBRQ1 requirements.
6.How does Aetrix verify that SN74AC238WBQBRQ1 is sourced from the original manufacturer or authorized distributors?
All SN74AC238WBQBRQ1 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 SN74AC238WBQBRQ1 meets industry standards.
7.What is the process for return or replacement of SN74AC238WBQBRQ1?
All SN74AC238WBQBRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC238WBQBRQ1, 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 SN74AC238WBQBRQ1 part is unused and in its original packaging.
Return procedure for SN74AC238WBQBRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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