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Texas Instruments CD74AC238M96
- Part No.:
- CD74AC238M96
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74AC238M96.pdf
- Description:
- IC DECODER/DEMUX 1X3:8 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,919
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Product details
Overview
CD74AC238M96 from Texas Instruments is a 3-line to 8-line decoder/demultiplexer IC designed for high-speed memory decoding and data-routing systems. It operates across 1.5 V to 5.5 V, delivers ±24 mA output drive, features three enable inputs (G1, G2A, G2B), and achieves propagation delays as low as 3.8 ns at 5 V - enabling use in fast-access memory subsystems and address decoding for microcontroller peripherals.
For engineers reviewing the CD74AC238M96 datasheet, CD74AC238M96 pinout, CD74AC238M96 application, or CD74AC238M96 equivalent, this device supports cascaded 24- and 32-line decoding without external inverters, offers balanced tPLH/tPHL timing, meets MIL-STD-883 ESD requirements (±2 kV HBM), and is validated for industrial temperature range (–55°C to 125°C) in SOIC-16 package.
Technical Context
The CD74AC238M96 implements active-high and active-low enable logic (G1, G2A, G2B) to select one of eight outputs (Y0–Y7) based on binary inputs A, B, C. Its CMOS architecture ensures SCR-latchup resistance and rail-to-rail output swing with defined VIH/VIL thresholds across supply voltages.
Propagation delay varies with VCC: 15 ns max at 5 V (–40°C to 85°C), 21 ns at 3.3 V, and 170 ns at 1.5 V, all measured into 50 pF load. Output drive capability remains stable across –55°C to 125°C, supporting robust operation in extended-temperature industrial control and instrumentation applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.5 V to 5.5 V - enables direct interface with 1.8 V, 3.3 V, and 5 V logic families without level shifters. |
| Max Propagation Delay (5 V) | 15 ns - ensures minimal added latency in high-speed memory decode paths, critical for sub-20 ns access time systems. |
| Output Drive Current | ±24 mA - supports fanout to 15 F-series devices or direct driving of moderate-capacitance buses. |
| ESD Rating (HBM) | ±2000 V - exceeds MIL-STD-883 requirement, reducing susceptibility to handling damage in manufacturing environments. |
| Operating Temperature | –55°C to 125°C - qualified for under-hood automotive, industrial PLC, and aerospace avionics applications. |
| Input Transition Rate | 20 ns/V (at 3.6–5.5 V) - defines minimum allowable input slew rate to avoid timing violations during fast edge transitions. |
| Power Dissipation Capacitance | 110 pF - used to calculate dynamic power (P = Cpd × V² × f), essential for thermal budgeting in dense logic arrays. |
Pinout & Package
CD74AC238M96 is housed in a 16-pin SOIC (D) package measuring 9.9 mm × 6.0 mm (body: 9.9 mm × 3.9 mm), with gull-wing leads and RoHS-compliant NiPdAu finish. Thermal resistance RθJA is 106.6°C/W, requiring standard PCB copper pour for thermal management in continuous operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A (1) | Binary Select Input | LSB of 3-bit address; must be tied to VCC or GND if unused to prevent floating-input-induced current leakage. |
| B (2) | Binary Select Input | Middle bit of address; determines Y1/Y3/Y5/Y7 activation when combined with A and C. |
| C (3) | Binary Select Input | MSB of address; selects upper or lower half of output set (Y4–Y7 vs. Y0–Y3). |
| G2A (4) | Active-Low Strobe Input | One of two enable controls; all outputs go high-impedance when G2A = HIGH, regardless of other inputs. |
| G2B (5) | Active-Low Strobe Input | Second active-low enable; both G2A and G2B must be LOW for decoding to occur (ANDed logic). |
| G1 (6) | Active-High Strobe Input | Primary enable; decoding only proceeds when G1 = HIGH AND G2A = G2B = LOW. |
| Y7 (7) | Active-Low Output | Selected output when A=B=C=HIGH; sinks current when enabled, requires pull-up for active-high logic. |
| GND (8) | Ground Reference | Return path for all internal circuitry; must be connected to low-impedance system ground plane. |
| Y6 (9) | Active-Low Output | Corresponds to address 110₂; asserted only when G1=HIGH, G2A=G2B=LOW, and A=0,B=1,C=1. |
| Y5 (10) | Active-Low Output | Asserted for address 101₂; used in priority encoder interfaces where discrete line assertion is required. |
| Y4 (11) | Active-Low Output | Upper-quadrant output for addresses 100₂; commonly routed to memory chip-select lines. |
| Y3 (12) | Active-Low Output | Lower-quadrant output for address 011₂; supports peripheral selection in multi-device I/O expansion. |
| Y2 (13) | Active-Low Output | Asserted for address 010₂; used in LED multiplexing or segmented display drivers requiring discrete gating. |
| Y1 (14) | Active-Low Output | Address 001₂ output; paired with Y0 for dual-channel signal routing in test equipment designs. |
| Y0 (15) | Active-Low Output | LSB output (000₂); often used as default enable path in fail-safe system initialization sequences. |
| VCC (16) | Positive Supply | Must be bypassed with 0.1 μF ceramic capacitor placed ≤2 mm from pin to suppress switching noise and maintain stable VCC. |
Key Features
| Feature | Design Value |
|---|---|
| Triple Enable Architecture | G1 (active-high) + G2A/G2B (active-low) allows hierarchical decoding without external gates - e.g., 24-line expansion uses two CD74AC238M96s with shared G2A/G2B and daisy-chained G1. |
| Rail-to-Rail Output Swing | VOH ≥ 4.4 V / VOL ≤ 0.1 V at 4.5 V supply - ensures full logic-level compatibility with TTL, LVTTL, and CMOS families across temperature. |
| Low-Power High-Speed Logic | ICC ≤ 160 μA at 5.5 V - consumes <1/10 the power of equivalent bipolar F-family decoders while matching speed performance. |
| SCR-Latchup Immunity | Tested per JEDEC JESD78 - prevents destructive latchup during transient overvoltage events in noisy industrial environments. |
| Input Noise Immunity | 30% of VCC - rejects common-mode noise up to 1.65 V at 5.5 V supply, improving reliability in electrically harsh settings. |
Applications
| Memory Address Decoding | Peripheral Device Selection |
|---|---|
|
Use Scenario: Selecting one of eight SRAM or Flash memory chips in a 16-bit embedded system with limited address lines. IC Role / Device Role / Timing Role: Translates 3-bit chip-select bus into individual /CS signals; propagation delay ≤15 ns avoids timing violations in sub-20 ns memory cycles. Use Value: Eliminates need for discrete NAND gates or additional logic, reducing BOM count and board area by 30% versus discrete solutions. |
Use Scenario: Routing UART, SPI, or GPIO signals to multiple sensors or actuators in an industrial controller. IC Role / Device Role / Timing Role: Acts as demultiplexer - G1 serves as data input, A/B/C select destination channel, Y0–Y7 drive enable pins. Use Value: Enables single-data-line broadcast with per-device enable control, simplifying firmware and reducing MCU pin usage. |
| High-Density Logic Expansion | Test Equipment Signal Routing |
|
Use Scenario: Building a 32-line decoder for FPGA configuration or FPGA I/O expansion using two CD74AC238M96s. IC Role / Device Role / Timing Role: First-stage CD74AC238M96 drives G1 inputs of second-stage units; G2A/G2B shared globally to minimize control lines. Use Value: Achieves full 32-line decode with only one external inverter (vs. four in conventional designs), cutting component cost by 25%. |
Use Scenario: Automated test fixture that routes stimulus signals to 8 DUTs (devices under test) based on controller command. IC Role / Device Role / Timing Role: Provides deterministic, glitch-free output selection via synchronous enable strobes (G1/G2A/G2B). Use Value: Ensures no spurious outputs during switching - critical for preventing false triggering in precision measurement circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar decoder/demultiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AC138N | Same 3-to-8 decode function, identical pinout (SOIC-16), but uses G1/G2′/G3′ enable scheme (two active-low, one active-high) - functionally identical to CD74AC238M96's G1/G2A/G2B. | Validated for commercial temp range (0°C to 70°C) only; lacks extended –55°C to 125°C qualification of CD74AC238M96. | Select SN74AC138N for cost-sensitive consumer applications where extended temperature is not required. |
| 74LVC138AD | Lower VCC range (1.65 V to 3.6 V), 32 mA output drive, 5.5 ns max tPD at 3.3 V - faster at 3.3 V but incompatible below 1.65 V. | Not rated for >3.6 V operation; cannot replace CD74AC238M96 in 5 V systems without level translation. | Choose 74LVC138AD only in 3.3 V-only designs demanding sub-6 ns timing and higher drive strength. |
Compared with SN74AC138N and 74LVC138AD, the CD74AC238M96 uniquely supports 1.5 V to 5.5 V operation across –55°C to 125°C, making it the sole option for wide-supply, extended-temperature industrial and automotive control modules requiring guaranteed timing and drive performance at voltage extremes.
Availability
CD74AC238M96 is available at Aetrix Electronics and suitable for memory address decoding, peripheral selection, logic expansion, and automated test equipment requiring stable component supply across industrial temperature ranges and mixed-voltage systems.
Supply support for CD74AC238M96 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 logic solutions, with over 50 years of innovation in high-reliability logic ICs.
The CD74AC238M96 belongs to TI's AC-series advanced CMOS logic family, engineered for high-speed, low-power memory and data-path applications in industrial, automotive, and communications infrastructure.
FAQ
What is the maximum operating supply voltage for CD74AC238M96?
The CD74AC238M96 supports a maximum supply voltage of 5.5 V, with absolute maximum rating at 6 V. Operation above 5.5 V risks exceeding recommended conditions and may degrade long-term reliability. The device is fully specified from 1.5 V to 5.5 V, enabling interoperability across 1.8 V, 3.3 V, and 5 V logic domains without level shifters - a key advantage of the AC-family design.
Does CD74AC238M96 support cascading for larger decoder configurations?
Yes, CD74AC238M96 supports cascading via its three enable inputs (G1, G2A, G2B). Two devices can implement a 24-line decoder without external inverters; a 32-line decoder requires only one external inverter. This architecture reduces gate count and propagation delay versus discrete NAND-based expansion, preserving timing margins in high-speed memory systems.
What is the thermal performance of CD74AC238M96 in SOIC-16 package?
The CD74AC238M96 in SOIC-16 (D package) has a junction-to-ambient thermal resistance (RθJA) of 106.6°C/W. With typical ICC ≤ 160 μA and output loading within ±24 mA limits, self-heating remains negligible in standard PCB layouts. For sustained high-output-current operation, a minimum 1-in² copper pour under the package is recommended to maintain junction temperature within –55°C to 125°C limits.
How does CD74AC238M96 handle unused inputs?
All unused inputs of CD74AC238M96 must be tied to VCC or GND - floating inputs cause increased ICC, unpredictable output states, and potential ESD vulnerability. The datasheet mandates this per TI application report SCBA004. For example, unused A, B, or C lines should connect to GND for fixed LSB/MID/MSB; unused enable lines must be held inactive (G2A/G2B = HIGH, G1 = LOW) to disable outputs.
Is CD74AC238M96 pin-compatible with industry-standard 3-to-8 decoders?
CD74AC238M96 is functionally and pin-compatible with SN74AC138N in SOIC-16 package: identical pin mapping (A–C, G1–G2B, Y0–Y7, VCC, GND) and logic behavior. However, it is not compatible with 74LS138 or 74HC138 due to differing enable polarity conventions and voltage thresholds - direct substitution requires verification of enable signal logic levels and supply compatibility.
CD74AC238M96 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 16-SOIC (0.154", 3.90mm 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 ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
CD74AC238M96 FAQ
1.How can I place an order for CD74AC238M96 through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74AC238M96 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 CD74AC238M96 reliable?
The price and inventory of CD74AC238M96 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74AC238M96 is usually 5 days.
3.What payment methods are accepted for CD74AC238M96?
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4.How is shipping managed for CD74AC238M96?
CD74AC238M96 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74AC238M96 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 CD74AC238M96?
For technical support, including CD74AC238M96 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74AC238M96 requirements.
6.How does Aetrix verify that CD74AC238M96 is sourced from the original manufacturer or authorized distributors?
All CD74AC238M96 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 CD74AC238M96 meets industry standards.
7.What is the process for return or replacement of CD74AC238M96?
All CD74AC238M96 units undergo pre-shipment inspection (PSI). If there is an issue with CD74AC238M96, 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 CD74AC238M96 part is unused and in its original packaging.
Return procedure for CD74AC238M96:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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