My Inquiry
My Account
Texas Instruments SN74HCS238QDYYRQ1
- Part No.:
- SN74HCS238QDYYRQ1
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- SOT-23-16 Thin, SOT-23 Variant
- Datasheet:
-
SN74HCS238QDYYRQ1.pdf
- Description:
- AUTOMOTIVE 3-TO-8 LINE DECODER D
- Quantity:
- Payment:
- Shipping:
Inventory:1,587
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74HCS238QDYYRQ1 from Texas Instruments is an automotive-qualified 3-to-8 line decoder/demultiplexer with Schmitt-trigger inputs, operating from 2 V to 6 V supply, delivering ±7.8-mA output drive at 6 V, and supporting –40°C to +125°C ambient temperature for memory selection and data routing in safety-critical vehicle subsystems.
For engineers reviewing the SN74HCS238QDYYRQ1 datasheet, SN74HCS238QDYYRQ1 pinout, SN74HCS238QDYYRQ1 application, or SN74HCS238QDYYRQ1 equivalent, key selection criteria include AEC-Q100 Grade 1 qualification, hysteresis-enabled noise immunity (ΔVT = 0.6 V min at 6 V), low ICC (100 nA typical), and SOT-23-THN (16-pin) package compatibility with space-constrained automotive control modules.
Technical Context
The SN74HCS238QDYYRQ1 implements a single 3:8 decoder with three address inputs (A2–A0) and three strobe inputs (G2, G1, G0), where outputs are normally low and only one goes high when enabled and selected. Its Schmitt-trigger inputs provide hysteresis (VT+ = 2.1 V, VT− = 1.2 V at 6 V), enabling robust operation with slow or noisy signals.
It features balanced CMOS push-pull outputs capable of sourcing/sinking ±7.8 mA at 6 V, with propagation delay as low as 7 ns (typical) and transition time ≤7 ns (typical) under 50-pF load. All outputs are forced low when any strobe is active, supporting cascaded decoding and demultiplexing functions in shared-bus architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 6 V - supports wide-input automotive power rails including 3.3 V and 5 V systems without level-shifting |
| Operating Temperature | –40°C to +125°C - qualified per AEC-Q100 Grade 1 for engine bay and ADAS ECU deployment |
| Output Drive Strength | ±7.8 mA at 6 V - sufficient to directly drive multiple CMOS inputs or small discrete loads without buffering |
| Input Hysteresis (ΔVT) | 0.6 V min at 6 V - rejects noise up to 600 mV peak-to-peak and tolerates slow edge rates (>1 µs) |
| Supply Current (ICC) | 100 nA typical at 6 V - enables ultra-low-power standby modes in always-on vehicle networks |
| Propagation Delay (tpd) | 7 ns typical at 6 V - ensures timing-critical address decoding meets sub-10 ns setup/hold windows |
| Input Leakage Current | ±100 nA max at 6 V - minimizes voltage divider errors in high-impedance bias networks |
Pinout & Package
SOT-23-THN (16-pin) package, 4.20 mm × 2.00 mm body size, thermal pad on bottom (not electrically connected unless tied to GND); designed for high-density PCB layouts in automotive sensor modules and body control units.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6 | A0, A1, A2, G0, G1, G2 | Address and strobe inputs - G0/G1 active-low, G2 active-high; enable/disable all outputs simultaneously |
| 7 | GND | Ground reference - must be low-impedance connection to minimize switching noise coupling |
| 8–15 | Y0–Y7 | Active-high decoded outputs - only one high at a time when strobes permit; open-drain behavior not supported |
| 16 | VCC | Positive supply - requires local 0.1-µF bypass capacitor placed within 2 mm of pin for stable high-speed operation |
| Thermal Pad | Thermal interface | Optional GND tie - improves thermal dissipation in thermally constrained modules; floating allowed per TI design guidance |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for automotive use across –40°C to +125°C ambient, including HBM ±4 kV and CDM ±1.5 kV ESD robustness |
| Schmitt-trigger input hysteresis | Enables reliable decoding of slow-rising sensor signals or noisy CAN/LIN bus-derived control lines without external filtering |
| Low ICC and IIL | 100 nA typical supply current and ±100 nA input leakage preserve battery life in always-on vehicle domains |
| Push-pull output architecture | Eliminates need for external pull-up resistors in chip-select applications, reducing BOM count and board area |
| Strobe-controlled output gating | Three independent strobes (G2, G1, G0) allow hierarchical enable logic for multi-layer memory or peripheral selection trees |
Applications
| Memory Address Decoding | Shared Data Bus Routing |
|---|---|
Use Scenario: Selecting one of eight flash or EEPROM devices sharing a common SPI or parallel data bus in an automotive infotainment head unit. IC Role / Device Role / Timing Role: Decoder providing chip-select (CS) signals synchronized to controller address lines with <10 ns propagation delay. Use Value: Reduces microcontroller GPIO usage by 5 pins versus individual CS lines while maintaining deterministic access timing. | Use Scenario: Enabling discrete power switches or signal multiplexers in a vehicle's body control module using a single 3-bit control bus. IC Role / Device Role / Timing Role: Demultiplexer converting serial control bits into parallel enable signals for eight independent load drivers. Use Value: Enables precise sequencing of lighting, HVAC, or door lock actuators with minimal firmware overhead and no timing skew between channels. |
| Engine Control Unit I/O Expansion | ADAS Sensor Interface Selection |
Use Scenario: Expanding limited MCU GPIOs to manage diagnostics LEDs, fault indicators, and status relays across multiple engine subsystems. IC Role / Device Role / Timing Role: Logic-level translator and selector driving 3.3 V or 5 V indicator loads with Schmitt-trigger noise rejection on noisy engine harness inputs. Use Value: Eliminates need for external RC filters on diagnostic input lines, simplifying layout and improving failure-in-time (FIT) reliability. | Use Scenario: Routing camera, radar, or ultrasonic sensor data paths to a central processor in a parking assist system. IC Role / Device Role / Timing Role: High-speed signal path selector enabling dynamic reconfiguration of sensor inputs without FPGA or complex switch ICs. Use Value: Supports <100 ns channel switching latency required for real-time sensor fusion, with no added jitter from passive analog switches. |
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 |
|---|---|---|---|
| SN74HCS138QDRQ1 | Same function but uses active-low outputs (Y0–Y7); lacks Schmitt-trigger inputs; identical AEC-Q100 Grade 1 rating | Requires external inverters for active-high loads; less tolerant of noisy or slow-rising control signals | Select when legacy designs mandate active-low outputs or when cost sensitivity outweighs noise immunity needs |
| MC74HC238ADTR2G | Industrial-grade (non-AEC-Q100); same pinout and logic function; no automotive qualification or extended temperature validation | Not approved for production automotive ECUs; suitable only for prototyping or non-safety-critical test fixtures | Choose only for bench validation where automotive qualification is not required |
Compared with SN74HCS138QDRQ1 and MC74HC238ADTR2G, the SN74HCS238QDYYRQ1 uniquely combines AEC-Q100 Grade 1 qualification, Schmitt-trigger inputs, and active-high outputs in a 4.2 mm × 2.0 mm SOT-23-THN package-enabling direct replacement in noise-prone engine compartment designs without layout or firmware changes.
Availability
SN74HCS238QDYYRQ1 is available at Aetrix Electronics and suitable for automotive infotainment, body control units, and ADAS sensor interface applications requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant traceability.
Supply support for SN74HCS238QDYYRQ1 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-grade logic solutions with over 50 years of automotive qualification experience.
The SN74HCS238QDYYRQ1 belongs to TI's HCS logic family-designed specifically for low-power, noise-immune automotive control applications where reliability across extreme temperature and EMI environments is mandatory.
FAQ
What is the maximum capacitive load the SN74HCS238QDYYRQ1 can drive while meeting datasheet timing specifications?
The SN74HCS238QDYYRQ1 is characterized for CL = 50 pF in its switching characteristics table. Propagation delay (tpd) and transition time (tt) values are guaranteed only up to this load. Driving >50 pF increases delay and may cause timing violations in high-speed address decoding; for heavier loads, add series termination or buffer stages. The SN74HCS238QDYYRQ1 itself does not specify derating curves beyond 50 pF.
Does the SN74HCS238QDYYRQ1 require external pull-up or pull-down resistors on unused inputs?
Yes - unused inputs on the SN74HCS238QDYYRQ1 must be terminated to VCC or GND to prevent floating states that cause increased ICC and potential logic oscillation. TI recommends 10-kΩ resistors for default HIGH or LOW biasing. Schmitt-trigger inputs do not eliminate this requirement; they only improve noise margin once biased.
Can the SN74HCS238QDYYRQ1 be used in a 1.8-V system?
No - the SN74HCS238QDYYRQ1 has a minimum recommended supply voltage of 2 V per Section 6.3. Operation below 2 V violates recommended conditions and risks undefined output states, excessive ICC, and failure to meet AEC-Q100 qualification limits. For 1.8-V systems, consider TI's SN74LVC138A or similar LVC-family decoders.
Is the thermal pad on the SN74HCS238QDYYRQ1 electrically connected to any internal node?
No - the thermal pad on the SN74HCS238QDYYRQ1 is not internally connected to any signal or power net. TI documentation states it may be left floating or connected to GND for improved thermal performance. It must never be connected to VCC or any other voltage rail, as this could create unintended current paths or violate absolute maximum ratings.
How does the strobe logic work on the SN74HCS238QDYYRQ1, and what happens when multiple strobes are asserted?
The SN74HCS238QDYYRQ1 has three strobes: G2 (active-high), G1 (active-low), and G0 (active-low). If any strobe is active (G2 = HIGH, or G1 = LOW, or G0 = LOW), all Y0–Y7 outputs are forced LOW regardless of address inputs. Multiple active strobes produce the same result - full output disable - with no priority encoding. This enables simple hierarchical gating in multi-stage decode trees.
SN74HCS238QDYYRQ1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCS
- Package/Case:
- SOT-23-16 Thin, SOT-23 Variant
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Decoder/Demultiplexer
- Circuit:
- 1 x 3:8
- Independent Circuits:
- 1
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOT-23-THIN
SN74HCS238QDYYRQ1 FAQ
1.How can I place an order for SN74HCS238QDYYRQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCS238QDYYRQ1 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 SN74HCS238QDYYRQ1 reliable?
The price and inventory of SN74HCS238QDYYRQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCS238QDYYRQ1 is usually 5 days.
3.What payment methods are accepted for SN74HCS238QDYYRQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCS238QDYYRQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCS238QDYYRQ1?
SN74HCS238QDYYRQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCS238QDYYRQ1 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 SN74HCS238QDYYRQ1?
For technical support, including SN74HCS238QDYYRQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCS238QDYYRQ1 requirements.
6.How does Aetrix verify that SN74HCS238QDYYRQ1 is sourced from the original manufacturer or authorized distributors?
All SN74HCS238QDYYRQ1 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 SN74HCS238QDYYRQ1 meets industry standards.
7.What is the process for return or replacement of SN74HCS238QDYYRQ1?
All SN74HCS238QDYYRQ1 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCS238QDYYRQ1, 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 SN74HCS238QDYYRQ1 part is unused and in its original packaging.
Return procedure for SN74HCS238QDYYRQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74HCS238QDYYRQ1 Tags
-
SN74HC138DR
Texas Instruments
-
TC7SB3157CFU,LF(CT
Toshiba Semiconductor and Storage
-
74CBTLV3257PW,118
Nexperia USA Inc.
-
SN74CBTLV3257PWR
Texas Instruments
-
74CBTLV3257GUX
Nexperia USA Inc.
-
74HC154BQ,118
Nexperia USA Inc.
-
P3S0200GMX
NXP USA Inc.
-
SN74CB3Q3245PWR
Texas Instruments
-
SN74CB3Q3257RGYR
Texas Instruments
-
TCA9543APWR
Texas Instruments
-
TCA9546APWR
Texas Instruments
-
SN74HC138N
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
