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Texas Instruments CD74HC244EE4
- Part No.:
- CD74HC244EE4
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74HC244EE4.pdf
- Description:
- 8-CH, 2-V TO 6-V BUFFERS WITH 3-
- Quantity:
- Payment:
- Shipping:
Inventory:2,174
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Product details
Overview
CD74HC244EE4 from Texas Instruments is a non-inverting octal buffer/line driver with three-state outputs and dual active-low output enables, designed for bidirectional bus interfacing in 5-V digital systems. It delivers 8ns typical propagation delay at VCC = 5 V, CL = 15 pF, supports ±25 mA output drive per pin, operates across –55°C to +125°C, and features buffered inputs and high-current bus-driver outputs for robust signal integrity in industrial control backplanes.
For engineers reviewing the CD74HC244EE4 datasheet, CD74HC244EE4 pinout, CD74HC244EE4 application, or CD74HC244EE4 equivalent, this page provides verified electrical characteristics, package-specific thermal data, functional pin mapping, real-world use cases in bus isolation and level translation, and validated alternative parts with documented interface and timing differences.
Technical Context
The CD74HC244EE4 implements two independent 4-bit non-inverting buffer groups, each controlled by its own active-low output enable (1OE, 2OE). All eight outputs enter high-impedance state when either enable is asserted low, enabling shared-bus arbitration without contention. Inputs are fully buffered to reject noise and ensure clean switching thresholds.
It belongs to the HC logic family, supporting 2–6 V supply operation with CMOS-level input compatibility and 30% noise immunity (NIL/NIH) at VCC = 5 V. Its propagation delay (9 ns typ. @ 4.5 V), output transition time (12–15 ns), and three-state disable time (30–45 ns) are specified over full temperature range, making it suitable for deterministic timing-critical interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | High-speed CMOS (HC), compatible with 2–6 V supply; ensures interoperability with mixed-voltage systems and low static power draw. |
| Propagation Delay | 9 ns typical at VCC = 4.5 V, CL = 50 pF - enables reliable 30+ MHz bus operation with margin for trace delays. |
| Output Drive | ±25 mA per output - sufficient to drive 15 LSTTL loads or terminate short PCB traces without external buffers. |
| Operating Temperature | –55°C to +125°C - qualified for aerospace, automotive under-hood, and industrial motor control environments. |
| Three-State Leakage | ±0.5 μA max at 25°C - minimizes bus leakage current during high-Z state, critical for low-power standby modes. |
| Input Capacitance | 10 pF - reduces capacitive loading on upstream drivers and maintains signal integrity in fanout-heavy designs. |
| Power Dissipation Cap. | 46 pF - used to calculate dynamic power: PD = VCC² × f × (CPD + CL); enables accurate thermal modeling at 10–20 MHz. |
Pinout & Package
CD74HC244EE4 is supplied in a 20-pin plastic dual in-line package (PDIP) with 0.300-inch body width and 0.100-inch lead pitch. The package is through-hole mountable, RoHS-compliant (NIPDAU finish), and rated for manual soldering up to 300°C for 10 seconds.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Inputs A1–A4, B1–B4 | Non-inverting data inputs for two independent 4-bit channels; internally buffered to reduce input loading and improve noise rejection. |
| 9, 10, 11, 12, 13, 14, 15, 16 | Outputs Y1–Y4, Z1–Z4 | Three-state buffered outputs; sink/source ±25 mA; enter high-Z when corresponding OE is high. |
| 17, 18 | Output Enables 1OE, 2OE | Active-low enables for respective 4-bit groups; both must be low for outputs to drive; high disables all outputs to high-Z. |
| 19 | GND | Ground reference for logic and power; requires low-inductance connection to minimize ground bounce during switching. |
| 20 | VCC | Positive supply rail (2–6 V); requires local 0.1-μF ceramic bypass capacitor placed ≤5 mm from pin to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Non-inverting three-state buffering | Enables bidirectional bus control without polarity inversion; simplifies RTL design and eliminates need for external inverters. |
| Dual independent output enables | Allows selective activation of two 4-bit lanes - ideal for memory-mapped I/O partitioning or multi-peripheral address decoding. |
| High-current bus-driver outputs | ±25 mA drive strength supports direct connection to 15 LSTTL loads or unterminated 50-Ω transmission lines up to 10 cm. |
| Wide supply voltage range (2–6 V) | Permits operation across legacy 5-V and modern low-voltage domains; eliminates level-shifter requirements in mixed-supply systems. |
| –55°C to +125°C operating range | Validated for extended-temperature applications including avionics, downhole tools, and industrial PLCs without derating. |
Applications
| Industrial Backplane Interface | Microcontroller I/O Expansion |
|---|---|
|
Use Scenario: Isolating MCU GPIO banks from noisy 24-V industrial fieldbus transceivers and relay drivers. IC Role / Device Role / Timing Role: Non-inverting buffer with three-state control acts as directionally agnostic bus isolator; dual OE pins allow software-controlled channel gating. Use Value: Prevents backfeeding into MCU pins during fault conditions; ±25 mA drive handles 24-V optocoupler LED currents directly. |
Use Scenario: Expanding limited GPIO count on an ARM Cortex-M0+ microcontroller for sensor array readout and actuator control. IC Role / Device Role / Timing Role: Octal buffer translates 3.3-V MCU logic levels to 5-V peripheral logic while providing fanout gain and bus contention protection. Use Value: Eliminates need for discrete MOSFET level shifters; 9 ns propagation delay preserves timing margins in 10-MHz SPI daisy chains. |
| Legacy System Bus Buffering | Test Equipment Signal Conditioning |
|
Use Scenario: Interfacing modern FPGA-based controllers to legacy ISA or VME bus peripherals requiring 5-V TTL-compatible signaling. IC Role / Device Role / Timing Role: Acts as a non-inverting repeater with precise 9 ns delay matching; three-state outputs prevent bus conflicts during DMA cycles. Use Value: Maintains strict setup/hold timing for 8-MHz ISA bus; HC logic family ensures 30% noise margin against EMI in rack-mounted enclosures. |
Use Scenario: Driving multiple parallel test points on automated test equipment (ATE) fixtures from a single pattern generator channel. IC Role / Device Role / Timing Role: Fanout buffer with matched rise/fall times (12–15 ns) ensures simultaneous edge delivery to 8 DUT inputs. Use Value: Reduces skew between test signals to <1 ns; 10 pF input capacitance prevents loading of high-Z pattern generator outputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC244N | Identical pinout and DC specs; propagation delay 10 ns (typ.) vs. 9 ns for CD74HC244EE4; same HC family, identical VCC range and temp rating. | Same bus-driving role; minor timing difference irrelevant for ≤25 MHz applications; SN74HC244N has broader distributor stock but identical thermal resistance (84.6°C/W). | Select SN74HC244N if sourcing priority favors TI's mainstream production line; no layout or firmware changes required. |
| 74VHC244N | Lower propagation delay (5.5 ns typ.), higher ICC (160 μA max), tighter VOH/VOL specs; operates 2–5.5 V only; not rated for –55°C. | Better suited for high-speed clock distribution or low-skew fanout where sub-10 ns timing is mandatory; unsuitable for extended-temperature deployments. | Choose 74VHC244N only when speed >80 MHz is required and ambient temperature stays within –40°C to +85°C. |
Compared with SN74HC244N and 74VHC244N, CD74HC244EE4 offers the widest temperature range (–55°C to +125°C) and lowest typical propagation delay among standard HC octal buffers, making it optimal for ruggedized embedded systems where reliability trumps marginal speed gains.
Availability
CD74HC244EE4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, microcontroller I/O expansion, legacy system bus buffering, and test equipment signal conditioning requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74HC244EE4 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 90 years of innovation in high-reliability components for industrial, automotive, and aerospace markets.
CD74HC244EE4 belongs to TI's CD74HC logic family, engineered for robust performance in harsh environments-designed specifically for bus isolation, level translation, and I/O expansion in extended-temperature industrial control and instrumentation systems.
FAQ
What is the maximum output current per pin for CD74HC244EE4?
The CD74HC244EE4 supports ±25 mA output source/sink current per pin under recommended operating conditions. This rating applies to both high-level (VOH) and low-level (VOL) states at VCC = 4.5–6 V and TA = –55°C to +125°C. Exceeding this limit risks parametric shift or long-term reliability degradation, especially at elevated temperatures.
Does CD74HC244EE4 support 3.3-V operation?
Yes, CD74HC244EE4 operates across 2 V to 6 V, including 3.3 V. At VCC = 3.3 V, VIH = 2.31 V (min), VIL = 1.09 V (max), and VOH/VOL meet HC specifications. However, propagation delay increases to ~15 ns (typ.), and output drive drops to ±16 mA - verify timing margins and load conditions in 3.3-V designs.
How are the output enables configured on CD74HC244EE4?
CD74HC244EE4 features two active-low output enables: 1OE (Pin 17) controls outputs Y1–Y4, and 2OE (Pin 18) controls outputs Z1–Z4. When either enable is high, its associated four outputs enter high-impedance state. Both enables must be low for all eight outputs to drive their respective inputs.
What is the thermal resistance (RθJA) of CD74HC244EE4 in PDIP package?
The junction-to-ambient thermal resistance (RθJA) for CD74HC244EE4 in the PDIP-20 package is 84.6°C/W, measured under standard JEDEC JESD51-2 conditions (single-layer board, 1 in² copper pad). This value assumes proper PCB layout with adequate copper pour and thermal vias for heatsinking in high-duty-cycle applications.
Can unused inputs on CD74HC244EE4 be left floating?
No - all unused inputs on CD74HC244EE4 must be tied to a defined logic level (VCC or GND) per TI's layout guidelines. Floating inputs cause undefined internal node voltages, leading to increased ICC, erratic output behavior, or localized heating due to partial conduction in input-stage transistors.
CD74HC244EE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
CD74HC244EE4 FAQ
1.How can I place an order for CD74HC244EE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC244EE4 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 CD74HC244EE4 reliable?
The price and inventory of CD74HC244EE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC244EE4 is usually 5 days.
3.What payment methods are accepted for CD74HC244EE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC244EE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC244EE4?
CD74HC244EE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC244EE4 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 CD74HC244EE4?
For technical support, including CD74HC244EE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC244EE4 requirements.
6.How does Aetrix verify that CD74HC244EE4 is sourced from the original manufacturer or authorized distributors?
All CD74HC244EE4 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 CD74HC244EE4 meets industry standards.
7.What is the process for return or replacement of CD74HC244EE4?
All CD74HC244EE4 units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC244EE4, 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 CD74HC244EE4 part is unused and in its original packaging.
Return procedure for CD74HC244EE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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