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Texas Instruments CD74HCT244E
- Part No.:
- CD74HCT244E
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74HCT244E.pdf
- Description:
- IC BUF NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,820
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Product details
Overview
CD74HCT244E from Texas Instruments is a non-inverting octal buffer/line driver with three-state outputs and dual active-low output enables (1OE, 2OE), designed for bidirectional bus interfacing in industrial control and data acquisition systems. It operates at 4.5 V to 5.5 V, delivers ±24 mA output drive per channel, exhibits 10 ns typical propagation delay at VCC = 5 V and CL = 15 pF, and supports –55°C to +125°C operation.
For engineers reviewing the CD74HCT244E datasheet, CD74HCT244E pinout, CD74HCT244E application, or CD74HCT244E equivalent, key selection criteria include LSTTL-compatible input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V), high-current bus driving capability, three-state bus contention avoidance, and wide-temperature reliability for embedded instrumentation and legacy system upgrades.
Technical Context
The CD74HCT244E implements two independent 4-bit non-inverting buffer sections, each controlled by its own active-low output enable (1OE for Y1–Y4, 2OE for Y5–Y8). All eight outputs enter high-impedance state when either enable is asserted low, enabling shared-bus arbitration without external logic.
Its HCT logic family ensures direct compatibility with standard TTL inputs while maintaining CMOS power efficiency. Input leakage remains ≤ ±1 μA, and three-state output leakage is ≤ ±5 μA over full temperature range, supporting stable bus hold and low standby current in multiplexed architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | HCT - TTL-compatible inputs, CMOS power efficiency, 4.5–5.5 V supply only |
| Propagation Delay | 10 ns typical (VCC = 5 V, CL = 15 pF, TA = 25°C) - enables reliable 30+ MHz bus operation |
| Output Drive | ±24 mA per channel - drives 15 LSTTL loads directly, eliminates need for external bus transceivers |
| Input Thresholds | VIL ≤ 0.8 V (max), VIH ≥ 2.0 V (min) - guarantees robust noise margin with legacy TTL sources |
| Operating Temperature | –55°C to +125°C - qualified for aerospace, automotive under-hood, and industrial PLC environments |
| Three-State Enable | Dual active-low OE pins (1OE, 2OE) - allows independent control of two 4-bit groups for flexible bus partitioning |
| Supply Current | ICC ≤ 160 μA (max, –55°C to +125°C) - supports low-power standby modes in battery-backed systems |
Pinout & Package
CD74HCT244E is supplied in a 20-pin plastic dual in-line package (PDIP, body size 25.40 mm × 6.35 mm), suitable for through-hole prototyping and legacy board assembly. Pin numbering follows standard DIP convention with notch-left orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | Inputs A1–A8 | Non-inverting data inputs; accept TTL-level signals directly without level-shifting |
| 9, 19 | Output Enables 1OE, 2OE | Active-low enables; asserting either disables corresponding Y-group (Y1–Y4 or Y5–Y8) |
| 11, 12, 13, 14, 15, 16, 17, 18 | Outputs Y1–Y8 | Three-state buffered outputs; high-impedance when respective OE is high |
| 10 | GND | Ground reference for all logic and output stages |
| 20 | VCC | Positive supply (4.5–5.5 V); requires local 0.1 μF bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| Non-inverting octal buffering | Preserves signal polarity across all 8 channels - simplifies timing analysis and eliminates inversion logic overhead |
| Dual independent output enables | Enables selective activation of two 4-bit segments - supports partial bus updates and memory-mapped I/O partitioning |
| LSTTL input compatibility | Accepts standard TTL VOH/VOL levels without external pull-ups - reduces BOM count in mixed-logic systems |
| High-current bus driving | ±24 mA sink/source per output - drives long traces, multiple receivers, or capacitive loads without buffers |
| Wide temperature operation | –55°C to +125°C guaranteed performance - eliminates derating calculations for harsh-environment deployments |
Applications
| Industrial Data Acquisition | Legacy System Bus Interface |
|---|---|
|
Use Scenario: Isolating ADC/DAC data buses from microcontroller address/data lines in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional buffer isolating high-noise analog subsystems from digital control logic while preserving signal integrity. Use Value: ±24 mA drive and 10 ns propagation delay ensure accurate sampling at >1 MSPS with minimal skew between channels. |
Use Scenario: Interfacing 8-bit microprocessors (e.g., 8085, Z80) to peripheral devices using shared address/data buses. IC Role / Device Role / Timing Role: Three-state octal driver enabling time-multiplexed bus access between CPU and peripherals. Use Value: Dual OE pins allow independent gating of I/O vs. memory address segments, reducing bus contention risk. |
| Automotive Sensor Signal Conditioning | Test Equipment Digital I/O Expansion |
|
Use Scenario: Buffering engine control unit (ECU) sensor inputs (e.g., crankshaft position, throttle) before ADC conversion. IC Role / Device Role / Timing Role: Noise-immune signal conditioner translating noisy analog sensor outputs into clean digital logic levels. Use Value: –55°C to +125°C rating and 30% noise immunity (at VCC = 5 V) ensure reliable operation near engine blocks. |
Use Scenario: Expanding GPIB or parallel port digital I/O capability in automated test equipment (ATE) racks. IC Role / Device Role / Timing Role: High-drive bus repeater extending signal reach across multi-slot backplanes with minimal jitter. Use Value: 15 LSTTL load fanout and low transition time (12–15 ns) maintain signal fidelity across 30 cm ribbon cables. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT244N | Identical logic function, pinout, and DC specs; TI's industry-standard variant with identical PDIP-20 packaging | No functional difference; same thermal and timing behavior across full temperature range | Select SN74HCT244N for second-source assurance where CD74HCT244E lead-time constraints exist |
| 74ACT244PC | Higher speed (tPD = 8.5 ns typ), wider supply (4.5–5.5 V), but higher ICC (200 μA max) and no –55°C rating | Limited to commercial/industrial temp (0°C to +70°C); unsuitable for extended-temperature deployments | Choose 74ACT244PC only when sub-10 ns timing is mandatory and ambient temperature stays below 70°C |
Compared with SN74HCT244N, CD74HCT244E offers identical functionality and qualification; versus 74ACT244PC, it trades minor speed reduction for guaranteed –55°C operation and lower quiescent current - critical for aerospace and automotive ECU designs.
Availability
CD74HCT244E is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74HCT244E 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and consumer applications.
CD74HCT244E belongs to TI's CD74HCT logic family, engineered for robust interoperability between TTL and CMOS systems in mission-critical industrial and automotive control environments.
FAQ
What is the maximum output current per pin for CD74HCT244E?
The CD74HCT244E provides ±24 mA output sink/source current per channel under recommended operating conditions (VCC = 4.5–5.5 V, TA = –55°C to +125°C). This rating enables direct driving of 15 LSTTL loads and supports reliable signal integrity on long PCB traces or ribbon cables without external amplification.
Does CD74HCT244E support operation at 3.3 V?
No. CD74HCT244E is an HCT-family device specified only for 4.5 V to 5.5 V operation. Its TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) are optimized for 5 V systems. For 3.3 V operation, consider TI's SN74LVC244A or compatible LVCMOS octal buffers instead of CD74HCT244E.
How are the output enables configured on CD74HCT244E?
CD74HCT244E features two active-low output enables: 1OE controls outputs Y1–Y4, and 2OE controls Y5–Y8. When either enable is low, its associated four outputs drive; when high, those outputs enter high-impedance state. This allows independent bus segment control without additional logic gates.
What is the typical propagation delay of CD74HCT244E at 5 V?
The typical propagation delay (tPLH/tPHL) of CD74HCT244E is 10 ns at VCC = 5 V, CL = 15 pF, and TA = 25°C. Maximum delay is 38 ns over the full –55°C to +125°C range, ensuring predictable timing margins in real-time control loops and synchronous data capture applications.
Is CD74HCT244E RoHS compliant?
Yes. The CD74HCT244E PDIP package uses NiPdAu (NIPDAU) lead finish and meets RoHS Directive 2011/65/EU requirements. It is rated for lead-free soldering processes and carries full material declaration compliance documentation from Texas Instruments.
CD74HCT244E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
CD74HCT244E FAQ
1.How can I place an order for CD74HCT244E through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT244E 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 CD74HCT244E reliable?
The price and inventory of CD74HCT244E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT244E is usually 5 days.
3.What payment methods are accepted for CD74HCT244E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT244E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HCT244E?
CD74HCT244E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT244E 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 CD74HCT244E?
For technical support, including CD74HCT244E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT244E requirements.
6.How does Aetrix verify that CD74HCT244E is sourced from the original manufacturer or authorized distributors?
All CD74HCT244E 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 CD74HCT244E meets industry standards.
7.What is the process for return or replacement of CD74HCT244E?
All CD74HCT244E units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT244E, 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 CD74HCT244E part is unused and in its original packaging.
Return procedure for CD74HCT244E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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