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Texas Instruments SN74AC138PWRQ1
- Part No.:
- SN74AC138PWRQ1
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AC138PWRQ1.pdf
- Description:
- Automotive 3-Line to 8-Line inv
- Quantity:
- Payment:
- Shipping:
Inventory:2,972
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Product details
Overview
SN74AC138PWRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive 3-line-to-8-line decoder/demultiplexer with three enable inputs (G2, G̅1, G̅0), 1.5V–6V supply range, ≤10.2ns propagation delay at 5V/50pF, and ±24mA continuous output drive. It functions as a memory address decoder in engine control units and body electronics where precise low-latency output selection is required.
For engineers reviewing the SN74AC138PWRQ1 datasheet, SN74AC138PWRQ1 pinout, SN74AC138PWRQ1 application, or SN74AC138PWRQ1 equivalent, key selection criteria include automotive temperature rating (–40°C to +125°C), wettable-flank WQFN-16 package compatibility with AOI inspection, dual active-low + one active-high enable architecture, and verified 50Ω transmission line drive capability.
Technical Context
The SN74AC138PWRQ1 implements a positive-logic 3-to-8 decoder with three binary address inputs (A0–A2) and three independent strobe inputs: one active-high (G2) and two active-low (G̅1, G̅0). All eight outputs (Y0–Y7) are active-low and open-drain–compatible push-pull, enabling direct connection to CMOS/TTL loads without external pull-ups.
Its functional truth table requires all three enables to be asserted simultaneously for any single output to go LOW; otherwise, all outputs remain HIGH. This triple-enable architecture eliminates need for external inverters in cascaded decoding-e.g., four SN74AC138PWRQ1 devices implement a 5-bit-to-32-line decoder using only one external inverter.
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) | 7.0ns (min) / 10.2ns (max) at 5V, 50pF - enables timing-critical address decoding in real-time automotive subsystems |
| Output Drive (Continuous) | ±24mA at 5V - sufficient to directly drive multiple CMOS inputs or small-signal LEDs without buffering |
| Output Drive (Short Burst) | ±75mA peak at 5V - allows brief high-current pulses for capacitive load charging or noise margin enhancement |
| Input Voltage Tolerance | Inputs accept up to 6V regardless of VCC - simplifies mixed-voltage system integration and prevents damage during hot-swap |
| AEC-Q100 Grade | Grade 1 (–40°C to +125°C ambient) - qualified for powertrain, chassis, and ADAS applications per automotive reliability standard |
| ESD Rating | HBM ±2000V, CDM ±1000V - meets automotive board-level ESD robustness requirements for under-hood environments |
Pinout & Package
SN74AC138PWRQ1 is available in two automotive-qualified packages: PW (16-pin TSSOP, 5mm × 6.4mm) and BQB (16-pin WQFN with wettable flanks, 3.5mm × 2.5mm). The BQB variant supports automated optical inspection (AOI) via side-fillet solder joints.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0, A1, A2 | Binary address inputs | Select one of eight outputs (Y0–Y7); decoded value appears as active-LOW on selected output |
| G2 | Active-high enable input | Must be HIGH for decoding; used as data input in demultiplexer mode when other enables are active |
| G̅1, G̅0 | Active-low enable inputs | Both must be LOW to enable outputs; reduce external gate count in multi-chip select systems |
| Y0–Y7 | Active-low decoded outputs | Only one output is LOW at any time when enabled; all others remain HIGH (push-pull, not open-drain) |
| VCC | Positive supply | Supplies internal logic and output drivers; bypass capacitor (0.1µF) required adjacent to pin |
| GND | Ground reference | Return path for all currents; low-inductance connection essential for signal integrity and EMI control |
Key Features
| Feature | Design Value |
|---|---|
| Triple Enable Architecture | One active-high (G2) and two active-low (G̅1, G̅0) enables allow flexible gating without external inverters in cascaded decoding |
| Wettable Flank QFN (BQB) | Enables reliable AOI inspection of solder joints on bottom-side terminations - critical for automotive manufacturing traceability |
| Wide-Voltage Operation | 1.5V–6V supply range permits direct use across legacy 5V and modern 1.8V/2.5V microcontroller interfaces |
| High-Speed Push-Pull Outputs | ≤10.2ns tpd at 5V/50pF and ±24mA drive support fast switching into 50Ω transmission lines or fan-out-of-10 CMOS loads |
| Automotive Qualification | AEC-Q100 Grade 1, HBM ±2000V, CDM ±1000V - validated for under-hood and safety-critical vehicle subsystems |
Applications
| Engine Control Unit (ECU) Memory Mapping | ADAS Camera Sensor Interface |
|---|---|
|
Use Scenario: Selecting among multiple flash memory banks or peripheral registers in a 32-bit MCU-based ECU. IC Role / Device Role / Timing Role: Address decoder that translates 3-bit chip-select signals into eight discrete low-active enables for memory-mapped peripherals. Use Value: Eliminates need for discrete logic gates or larger CPLDs; reduces BOM count and PCB area while maintaining <11ns timing margin at 5V operation. |
Use Scenario: Routing serialized sensor data from multiple camera modules to a central image processor in lane-departure warning systems. IC Role / Device Role / Timing Role: Demultiplexer using G2 as data input and A0–A2 as channel address to steer pixel streams across eight parallel paths. Use Value: Enables deterministic latency (<10.2ns) and simultaneous channel isolation - critical for synchronized multi-camera capture timing. |
| Body Control Module (BCM) I/O Expansion | Electric Power Steering (EPS) Fault Monitoring |
|
Use Scenario: Expanding limited GPIO count of a low-cost MCU to manage 8 independent lighting zones or door lock actuators. IC Role / Device Role / Timing Role: Output selector that converts 3 MCU pins into 8 independently controllable low-side switch enables. Use Value: Provides ±24mA drive per output - sufficient to directly drive small relays or MOSFET gates without external buffers, reducing component count. |
Use Scenario: Monitoring 8 independent motor phase current sensors or position feedback lines in EPS torque assist circuits. IC Role / Device Role / Timing Role: Fault signal aggregator that pulls a dedicated diagnostic line LOW when any monitored sensor fails its self-test. Use Value: Leverages active-low outputs and triple-enable logic to implement fail-safe diagnostics with zero additional logic; meets ISO 26262 ASIL-B timing constraints. |
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 drive (±6mA), slower tpd (17ns max at 3.3V), LV-CMOS process | Better suited for ultra-low-power body electronics; insufficient for 50Ω line driving or fast ECU timing | Choose when supply voltage is fixed at 1.8V–3.3V and speed <15ns is acceptable |
| MC74AC138DG | Industrial temp range (–40°C to +85°C), no AEC-Q100 qualification, SOIC-16 package | Lacks automotive qualification and wettable flank; unsuitable for safety-critical or production automotive use | Acceptable only for prototyping or non-automotive industrial systems |
Compared with SN74LV138AQPWRQ1 and MC74AC138DG, the SN74AC138PWRQ1 uniquely delivers automotive-grade speed (≤10.2ns), robust ±24mA drive, and AOI-compatible packaging - making it the only option qualified for timing-sensitive powertrain and ADAS subsystems.
Availability
SN74AC138PWRQ1 is available at Aetrix Electronics and suitable for engine control units, ADAS camera interfaces, body control modules, and electric power steering systems requiring stable component supply across automotive production lifecycles.
Supply support for SN74AC138PWRQ1 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 SN74AC138PWRQ1 belongs to TI's automotive logic portfolio, engineered specifically for high-reliability address decoding and signal routing in engine management, chassis control, and driver-assistance electronics.
FAQ
What is the maximum operating temperature for SN74AC138PWRQ1?
The SN74AC138PWRQ1 is AEC-Q100 Grade 1 qualified with a guaranteed operating free-air temperature range of –40°C to +125°C. This rating applies to both the PW (TSSOP) and BQB (WQFN) package variants and is validated across full electrical specifications including propagation delay, output drive, and leakage current.
Does SN74AC138PWRQ1 support 1.8V logic levels?
Yes, SN74AC138PWRQ1 fully supports 1.8V operation: VIH(min) = 1.26V and VIL(max) = 0.54V at VCC = 1.8V, with tpd of 16.2ns (tPLH) / 18.1ns (tPHL) under 50pF load. Its 1.5V–6V supply range ensures interoperability with modern low-voltage microcontrollers without level translation.
Can SN74AC138PWRQ1 drive a 50Ω transmission line directly?
Yes, SN74AC138PWRQ1 is explicitly characterized to drive 50Ω transmission lines. Its balanced CMOS push-pull outputs deliver clean edges into such loads at 5V supply, with typical VOL < 0.5V and VOH > 4.5V at 24mA - meeting impedance-matching and signal-integrity requirements for automotive serial bus stubs and sensor interfaces.
What is the purpose of the thermal pad in the BQB package of SN74AC138PWRQ1?
The thermal pad in the SN74AC138PWRQ1 BQB (WQFN) package may be connected to GND or left floating - it must not be connected to any other signal or supply. When tied to GND, it improves thermal dissipation (RθJB = 67.6°C/W) and provides additional ESD current shunting; floating configuration maintains signal isolation in sensitive analog sections.
How does the triple-enable architecture of SN74AC138PWRQ1 reduce external component count?
The SN74AC138PWRQ1 integrates one active-high (G2) and two active-low (G̅1, G̅0) enables, allowing direct connection to MCU GPIOs without inverters. For example, expanding to 32 outputs requires only four SN74AC138PWRQ1 devices and one external inverter - versus six devices and multiple gates with single-enable decoders.
SN74AC138PWRQ1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- 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:
- 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
- Supplier Device Package:
- 16-TSSOP
SN74AC138PWRQ1 FAQ
1.How can I place an order for SN74AC138PWRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC138PWRQ1 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 SN74AC138PWRQ1 reliable?
The price and inventory of SN74AC138PWRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC138PWRQ1 is usually 5 days.
3.What payment methods are accepted for SN74AC138PWRQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AC138PWRQ1 transactions.
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4.How is shipping managed for SN74AC138PWRQ1?
SN74AC138PWRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC138PWRQ1 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 SN74AC138PWRQ1?
For technical support, including SN74AC138PWRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC138PWRQ1 requirements.
6.How does Aetrix verify that SN74AC138PWRQ1 is sourced from the original manufacturer or authorized distributors?
All SN74AC138PWRQ1 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 SN74AC138PWRQ1 meets industry standards.
7.What is the process for return or replacement of SN74AC138PWRQ1?
All SN74AC138PWRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC138PWRQ1, 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 SN74AC138PWRQ1 part is unused and in its original packaging.
Return procedure for SN74AC138PWRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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