Octal D-Type Flip-Flops with Reset 20-SSOP -55 to 125# CD74ACT273SM96G4 Octal D-Type Flip-Flop with Clear Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The CD74ACT273SM96G4 serves as an 8-bit data storage register in digital systems, primarily functioning as:
- Data buffering and synchronization between asynchronous systems
- Temporary storage element in microprocessor interfaces
- Pipeline registers in digital signal processing architectures
- State machine implementation for control logic circuits
- Input/output port expansion in microcontroller systems
### Industry Applications
Computing Systems:
- CPU register files and cache memory interfaces
- Bus interface units for data width conversion
- Peripheral controller state registers
Communication Equipment:
- Data packet buffering in network switches
- Serial-to-parallel conversion registers
- Protocol handler state storage
Industrial Control:
- PLC input/output conditioning circuits
- Motor control state registers
- Sensor data acquisition systems
Consumer Electronics:
- Display controller line buffers
- Audio processing sample registers
- Remote control code storage
### Practical Advantages
Strengths:
- High-speed operation with 5.5V CMOS technology (typ. 10ns propagation delay)
- Low power consumption (4mA ICC max) compared to bipolar alternatives
- Wide operating voltage range (4.5V to 5.5V) for robust performance
- Direct TTL compatibility without need for interface components
- Synchronous clear function for controlled system initialization
Limitations:
- Limited voltage range compared to modern 3.3V systems
- No tri-state outputs restricts bus sharing capabilities
- Fixed edge-triggering limits flexibility in some timing scenarios
- Package constraints (SOIC-20) may not suit space-constrained applications
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Timing Violations:
- Problem: Setup/hold time violations causing metastability
- Solution: Ensure minimum 5ns setup time and 0ns hold time relative to clock edge
Power Supply Noise:
- Problem: ACT logic susceptibility to power supply transients
- Solution: Implement 0.1μF decoupling capacitors within 0.5" of VCC pin
Clock Distribution:
- Problem: Clock skew between multiple flip-flops
- Solution: Use balanced clock tree with matched trace lengths
### Compatibility Issues
Voltage Level Compatibility:
- With 3.3V Logic: Requires level shifters for reliable operation
- With 5V TTL: Direct compatibility with proper current considerations
- With CMOS: Compatible but ensure proper input voltage thresholds
Loading Considerations:
- Maximum fanout: 50 LSTTL loads (ACT series drive capability)
- Capacitive loading: Limit to 50pF for maintaining specified timing
### PCB Layout Recommendations
Power Distribution:
- Use star-point grounding for analog and digital sections
- Implement separate VCC and GND planes for noise immunity
- Place decoupling capacitors (0.1μF ceramic) adjacent to power pins
Signal Integrity:
- Route clock signals first with controlled impedance
- Maintain 3W rule for parallel trace spacing
- Keep critical paths (clock-to-output) under 2 inches
Thermal Management:
- Provide adequate copper pour for heat dissipation
- Ensure minimum 0.5mm clearance for SOIC-20 package
- Consider thermal vias for high-frequency operation
## 3. Technical Specifications
### Key Parameter Explanations
DC Characteristics:
- VOH (Output High Voltage): 4.4V min @ IOH = -24mA
- VOL (
