Octal Non-Inverting Buffers/Line Drivers with 3-State Outputs# CD74ACT244M96 Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The CD74ACT244M96 octal buffer/line driver serves as a fundamental interface component in digital systems, primarily functioning as:
Signal Buffering Applications
- Bus Driving : Provides high-current drive capability (24mA) for driving heavily loaded data/address buses in microprocessor systems
- Signal Isolation : Prevents loading effects between different circuit sections while maintaining signal integrity
- Level Translation : Interfaces between components operating at different voltage levels within the 2V to 6V range
Timing Critical Systems
- Clock Distribution : Low propagation delay (typically 8.5ns at 5V) makes it suitable for clock tree distribution
- Synchronization Circuits : Maintains signal timing across multiple system domains
- Pipeline Stages : Acts as temporary storage elements in pipelined architectures
### Industry Applications
Computing Systems
- Memory Interface : Buffers address and control signals for DRAM/SRAM modules
- Peripheral Connectivity : Drives signals to external devices through parallel ports
- Backplane Driving : Handles long trace runs in backplane architectures
Industrial Electronics
- PLC Systems : Interfaces between control logic and field devices
- Motor Control : Buffers control signals to power drivers in motor control systems
- Sensor Networks : Conditions digital signals from multiple sensor inputs
Communication Equipment
- Telecom Switching : Handles multiple digital channels in switching matrices
- Network Interface : Buffers data lines in network interface cards
- Digital Signal Processing : Interfaces between DSP processors and peripheral components
### Practical Advantages and Limitations
Advantages
- High-Speed Operation : ACT technology provides TTL-compatible inputs with CMOS output levels
- Robust Output Drive : Capable of driving 50pF loads while maintaining signal integrity
- Low Power Consumption : Typical ICC of 8μA (static) makes it suitable for power-sensitive applications
- Wide Operating Range : 2V to 6V supply voltage accommodates various system requirements
- ESD Protection : 2kV HBM protection enhances reliability in harsh environments
Limitations
- Limited Current Sink/Source : Maximum 24mA per output may require additional drivers for high-current applications
- Propagation Delay Variation : Timing varies with temperature, voltage, and load conditions
- Simultaneous Switching Noise : Multiple outputs switching simultaneously can cause ground bounce
- Package Constraints : SOIC-20 package limits power dissipation to 500mW
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Power Supply Decoupling
- Pitfall : Inadequate decoupling causing signal integrity issues and ground bounce
- Solution : Place 0.1μF ceramic capacitor within 0.5" of VCC pin, with bulk 10μF capacitor per every 4-5 devices
Simultaneous Switching Effects
- Pitfall : Multiple outputs switching simultaneously creating ground bounce and VCC sag
- Solution : Implement staggered output enable signals or add series termination resistors (22-33Ω)
Signal Integrity Issues
- Pitfall : Ringing and overshoot on long transmission lines
- Solution : Use series termination matching trace impedance (typically 50-75Ω)
### Compatibility Issues
Mixed Voltage Systems
- TTL Compatibility : Inputs are TTL-voltage compatible (VIL = 0.8V max, VIH = 2.0V min)
- CMOS Interface : Outputs provide full CMOS logic levels when driving CMOS inputs
- Level Translation : Can interface between 3.3V and 5V systems with proper consideration of VIH/VIL levels
Timing Constraints
- Setup/Hold
