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Texas Instruments CD74AC244E
- Part No.:
- CD74AC244E
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74AC244E.pdf
- Description:
- IC BUFF NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:557
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Product details
Overview
CD74AC244E from Texas Instruments is an octal 3-state non-inverting buffer/line driver in PDIP-20 package, operating from 1.5 V to 5.5 V with ±24 mA output drive, balanced propagation delays (max 10.1 ns at 5 V), and SCR-latch-up-resistant CMOS process - used for bidirectional bus interfacing in industrial control backplanes.
For engineers reviewing the CD74AC244E datasheet, CD74AC244E pinout, CD74AC244E application, or CD74AC244E equivalent, key selection criteria include 3-state output enable timing (tPZL/tPLZ ≤ 18 ns), 50-Ω transmission-line drive capability, input voltage thresholds (VIH = 3.85 V min at VCC = 5.5 V), and thermal performance (RθJA = 40 °C/W in PDIP).
Technical Context
The CD74AC244E implements two independent 4-bit banks (Bank 1: pins 1Y0–1Y3; Bank 2: 2Y0–2Y3), each controlled by active-low output enables (1OE, 2OE). Its RCA Advanced CMOS process delivers bipolar FAST-speed performance with CMOS power efficiency.
It supports wide supply range (1.5–5.5 V) and exhibits balanced noise immunity (30% of VCC), enabling robust operation in mixed-voltage systems. Input leakage remains ≤±1 μA over −40°C to +85°C, and 3-state leakage is ≤±5 μA under same conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 1.5 V to 5.5 V - enables interoperability with 1.8 V, 3.3 V, and 5 V logic domains without level shifters. |
| Output Drive | ±24 mA per output - sufficient to fan out to 15 FAST ICs or directly drive 50 Ω PCB traces. |
| Propagation Delay | Max 10.1 ns (tPHL/tPLH at VCC = 5 V, TA = −40°C to +85°C) - ensures timing compliance in high-speed address/data buses. |
| 3-State Enable/Disable | tPZL/tPLZ ≤ 18 ns (VCC = 5 V) - minimizes bus contention windows during direction switching. |
| Input Thresholds | VIH = 3.85 V min, VIL = 1.65 V max at VCC = 5.5 V - provides 0.9 V noise margin against TTL-compatible inputs. |
| Thermal Resistance | RθJA = 40 °C/W (PDIP-20) - allows sustained operation up to 85°C ambient with minimal heatsinking. |
| Quiescent Current | ICC ≤ 80 μA (TA = −40°C to +85°C) - supports low-power standby modes in battery-backed systems. |
Pinout & Package
CD74AC244E is supplied in 20-pin plastic dual-in-line package (PDIP-N), body size 24.33 mm × 6.35 mm, with through-hole mounting and industry-standard pin spacing (2.54 mm).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Active-low output enable (Bank 1) | Asserting low enables outputs 1Y0–1Y3; high places them in high-impedance state - critical for bus arbitration. |
| 1A0–1A3 | Inputs (Bank 1) | Non-inverting data inputs for first 4-bit channel - routed to corresponding 1Y0–1Y3 outputs when 1OE is low. |
| 1Y0–1Y3 | Outputs (Bank 1) | Buffered non-inverting outputs for Bank 1 - drive external loads while isolating upstream logic during 3-state. |
| 2OE | Active-low output enable (Bank 2) | Independent control of second 4-bit bank; enables concurrent or staggered bus access. |
| 2A0–2A3 | Inputs (Bank 2) | Non-inverting inputs for second 4-bit channel - electrically isolated from Bank 1 for differential routing. |
| 2Y0–2Y3 | Outputs (Bank 2) | Buffered outputs for Bank 2 - support dual-bus architectures (e.g., address vs. data separation). |
| GND (Pin 10) | Ground reference | Primary return path for all I/O and supply currents - must be low-inductance connection to minimize ground bounce. |
| VCC (Pin 20) | Positive supply | Single supply rail powering both banks - requires local 0.1 µF ceramic bypass capacitor per VCC pin. |
Key Features
| Feature | Design Value |
|---|---|
| SCR-latch-up resistance | Guaranteed per JEDEC JESD78 - eliminates risk of destructive latch-up in noisy industrial environments. |
| Balanced propagation delays | Matched tPLH/tPHL within 1 ns - prevents skew-induced setup/hold violations across multi-bit buses. |
| Wide supply range | 1.5 V to 5.5 V operation - supports direct interface with legacy 5 V microcontrollers and modern 1.8 V FPGAs. |
| 50 Ω transmission-line drive | Validated at +85°C - enables point-to-point routing on impedance-controlled PCBs without external termination. |
| 30% supply noise immunity | VIH/VIL thresholds scale with VCC - maintains noise margin across full voltage range without recalibration. |
Applications
| Industrial Backplane Interface | Microcontroller Bus Expansion |
|---|---|
|
Use Scenario: Isolating and driving 8-bit parallel data between a PLC CPU module and remote I/O expansion cards over 15 cm PCB traces. IC Role / Device Role / Timing Role: Non-inverting 3-state buffer providing bidirectional signal conditioning and bus contention control. Use Value: ±24 mA drive sustains signal integrity across long traces; tPZL ≤ 18 ns prevents glitches during hot-swap insertion. |
Use Scenario: Extending GPIO count of an ARM Cortex-M4 MCU to drive 16-segment LED displays and keypad scan matrix. IC Role / Device Role / Timing Role: Octal buffer decoupling MCU pins from capacitive display loads while enabling shared data bus access. Use Value: Low ICC (≤80 μA) extends battery life; 1.5 V minimum VCC supports ultra-low-voltage sleep modes. |
| Test Equipment Signal Routing | Legacy System Voltage Translation |
|
Use Scenario: Multiplexing test signals between FPGA-based pattern generator and DUT socket in automated test equipment. IC Role / Device Role / Timing Role: 3-state line driver enabling dynamic reconfiguration of signal paths without hardware changes. Use Value: Matched propagation delays (<10.1 ns) preserve timing margins; RθJA = 40 °C/W supports continuous 100 MHz toggling. |
Use Scenario: Interfacing 3.3 V SoC peripherals with 5 V legacy sensors and actuators in building automation controllers. IC Role / Device Role / Timing Role: Level-shifting buffer leveraging VCC-tolerant inputs and rail-to-rail output swing. Use Value: VIH = 3.85 V min at 5.5 V ensures reliable recognition of 3.3 V logic highs; no external level translators required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AC244N | Identical AC-series electrical specs and pinout; TI's current production version with updated MSL rating (Level-1-260°C). | Same industrial temperature range (−40°C to +85°C); RoHS-compliant NIPDAU finish replaces legacy tin-lead. | Select SN74AC244N for new designs requiring long-term availability and lead-free compliance. |
| CD74ACT244E | TTL-compatible input thresholds (VIH = 2.0 V min), higher drive (±24 mA), but narrower VCC range (4.5–5.5 V only). | Optimized for 5 V-only systems with legacy TTL inputs; not suitable for mixed-voltage or sub-3.3 V operation. | Choose CD74ACT244E only when interfacing exclusively with 5 V TTL logic and requiring guaranteed 2.0 V VIH. |
Compared with CD74AC244E, SN74AC244N offers identical functionality with enhanced manufacturability and lifecycle support, while CD74ACT244E trades supply flexibility for stricter TTL compatibility - making CD74AC244E the optimal choice for multi-rail embedded systems.
Availability
CD74AC244E is available at Aetrix Electronics and suitable for industrial backplane interfaces, microcontroller bus expansion, test equipment signal routing, and legacy system voltage translation requiring stable component supply across extended temperature ranges.
Supply support for CD74AC244E 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 connectivity technologies with over 90 years of innovation in industrial, automotive, and communications markets.
The CD74AC244E belongs to TI's legacy CD74AC logic family, designed specifically for high-reliability, wide-supply-range buffering in industrial control, instrumentation, and legacy system upgrades where latch-up immunity and timing predictability are critical.
FAQ
What is the maximum operating temperature range for the CD74AC244E?
The CD74AC244E is rated for operation from −40°C to +85°C, matching the commercial/industrial temperature grade. This range is validated per TI's recommended operating conditions and supported by thermal metrics (RθJA = 40 °C/W in PDIP), ensuring reliability in factory automation and outdoor control enclosures where ambient temperatures exceed 70°C.
Does the CD74AC244E support 3.3 V logic systems?
Yes, the CD74AC244E fully supports 3.3 V operation: its supply range (1.5 V to 5.5 V) includes 3.3 V nominal rails, and input thresholds scale accordingly (VIH ≈ 2.31 V min, VIL ≈ 0.99 V max at VCC = 3.3 V). This enables direct interface with 3.3 V FPGAs, microcontrollers, and memory devices without level translation.
How does the CD74AC244E handle bus contention during 3-state transitions?
The CD74AC244E minimizes bus contention via fast, matched 3-state timing: tPZL and tPLZ are both ≤18 ns at VCC = 5 V, ensuring outputs enter high-impedance rapidly after enable deassertion. Combined with balanced tPLH/tPHL delays, this prevents overlap between driving and floating states on shared buses.
Can the CD74AC244E drive 50 Ω transmission lines reliably?
Yes, the CD74AC244E is explicitly characterized for 50 Ω transmission-line drive at +85°C per TI's datasheet (Section 4.4, footnote 2). Its ±24 mA output capability ensures clean edge integrity on controlled-impedance traces up to 15 cm, eliminating need for external series termination resistors in most board-level applications.
What is the purpose of the two independent output enables (1OE and 2OE) on the CD74AC244E?
The dual active-low output enables (1OE for pins 1Y0–1Y3; 2OE for 2Y0–2Y3) allow independent control of two 4-bit data channels. This enables time-multiplexed bus access, partial bus isolation (e.g., holding address lines active while releasing data lines), and reduced system-level contention in multi-master architectures - a key advantage over single-enable octal buffers.
CD74AC244E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Logic Type:
- Buffer, Non-Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 1.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
CD74AC244E FAQ
1.How can I place an order for CD74AC244E through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74AC244E 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 CD74AC244E reliable?
The price and inventory of CD74AC244E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74AC244E is usually 5 days.
3.What payment methods are accepted for CD74AC244E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74AC244E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74AC244E?
CD74AC244E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74AC244E 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 CD74AC244E?
For technical support, including CD74AC244E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74AC244E requirements.
6.How does Aetrix verify that CD74AC244E is sourced from the original manufacturer or authorized distributors?
All CD74AC244E 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 CD74AC244E meets industry standards.
7.What is the process for return or replacement of CD74AC244E?
All CD74AC244E units undergo pre-shipment inspection (PSI). If there is an issue with CD74AC244E, 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 CD74AC244E part is unused and in its original packaging.
Return procedure for CD74AC244E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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