Encyclopedia Entry: 74AC240TTR

Product Overview

• Category: Integrated Circuit (IC)
• Use: Signal Buffer/Line Driver
• Characteristics: High-speed, low-power, octal buffer with 3-state outputs
• Package: TSSOP-20
• Essence: The 74AC240TTR is a versatile integrated circuit that provides buffering and line driving capabilities for digital signals.
• Packaging/Quantity: Available in tape and reel packaging, with 2500 units per reel.

Specifications

• Supply Voltage: 2V to 6V
• Input Voltage: 0V to VCC
• Output Voltage: 0V to VCC
• Operating Temperature Range: -40°C to +85°C
• Propagation Delay: 5.5 ns (typical)
• Output Drive Capability: ±24 mA

Detailed Pin Configuration

The 74AC240TTR IC has a total of 20 pins, which are assigned specific functions as follows:

1. A1: Input A1
2. Y1: Output Y1
3. A2: Input A2
4. Y2: Output Y2
5. GND: Ground
6. A3: Input A3
7. Y3: Output Y3
8. A4: Input A4
9. Y4: Output Y4
10. OE: Output Enable
11. Y5: Output Y5
12. A5: Input A5
13. Y6: Output Y6
14. A6: Input A6
15. Y7: Output Y7
16. A7: Input A7
17. Y8: Output Y8
18. VCC: Supply Voltage
19. GND: Ground
20. A8: Input A8

Functional Features

• Octal buffer with 3-state outputs
• High-speed operation, suitable for use in fast digital systems
• Low power consumption, making it energy-efficient
• 3-state outputs allow multiple devices to share a common bus without interference
• Schmitt-trigger inputs provide hysteresis and improve noise immunity

Advantages and Disadvantages

Advantages: - High-speed operation enables efficient data transfer - Low power consumption reduces energy usage - 3-state outputs facilitate bus sharing in complex systems - Schmitt-trigger inputs enhance noise immunity

Disadvantages: - Limited output drive capability may not be suitable for high-current applications - Propagation delay of 5.5 ns may introduce timing issues in certain scenarios

Working Principles

The 74AC240TTR is designed as an octal buffer with 3-state outputs. It operates by receiving digital input signals on the A1-A8 pins and providing buffered outputs on the Y1-Y8 pins. The OE (Output Enable) pin controls the 3-state outputs, allowing them to be either active or in a high-impedance state.

When the OE pin is low, the outputs are enabled and actively driven by the internal circuitry. Conversely, when the OE pin is high, the outputs enter a high-impedance state, effectively disconnecting them from the external circuitry.

The Schmitt-trigger inputs ensure that the IC's inputs have hysteresis, which improves noise immunity and provides more reliable signal detection.

Detailed Application Field Plans

The 74AC240TTR is widely used in various digital systems where buffering and line driving capabilities are required. Some common application fields include: - Microprocessor-based systems - Data communication equipment - Industrial automation systems - Automotive electronics - Consumer electronics

Detailed and Complete Alternative Models

• 74HC240: Similar octal buffer with 3-state outputs, compatible with 5V systems
• 74ACT240: Octal buffer with 3-state outputs, designed for faster operation at 5V
• SN74LS240: Octal buffer with 3-state outputs, suitable for use in 5V TTL logic systems

These alternative models offer similar functionality to the 74AC240TTR but may have different voltage compatibility or operating characteristics.

In conclusion, the 74AC240TTR is a versatile integrated circuit that provides high-speed buffering and line driving capabilities. Its low power consumption, 3-state outputs, and Schmitt-trigger inputs make it suitable for various digital applications. However, its limited output drive capability and propagation delay should be considered when selecting this IC for specific projects.