CMOS Octal Latching Bus Driver# Technical Documentation: CP82C82 CMOS Dual Retriggerable Monostable Multivibrator
Manufacturer : Harris Semiconductor (now part of Intersil/Renesas)
## 1. Application Scenarios
### Typical Use Cases
The CP82C82 is a dual retriggerable monostable multivibrator primarily employed in digital timing and pulse generation applications:
- Pulse Width Extension : Extending short input pulses to predetermined durations
- Time Delay Generation : Creating precise delays in digital systems
- Missing Pulse Detection : Monitoring pulse trains for missing or delayed pulses
- Frequency Division : Dividing input frequencies by integer ratios
- Debouncing Circuits : Cleaning mechanical switch contacts in digital interfaces
### Industry Applications
Industrial Control Systems :
- Machine timing sequences in automated manufacturing
- Safety interlock timing in hazardous environments
- Process control event sequencing
Communications Equipment :
- Bit synchronization in data transmission systems
- Timing recovery circuits in modem designs
- Frame synchronization in telecommunication systems
Computer Peripherals :
- Disk drive head positioning timing
- Printer carriage control timing
- Keyboard scanning interval generation
Automotive Electronics :
- Engine management system timing functions
- Anti-lock braking system pulse monitoring
- Dashboard display refresh timing
### Practical Advantages and Limitations
Advantages :
- Wide operating voltage range : 3V to 18V DC
- Low power consumption : Typical ICC = 10μA (quiescent)
- High noise immunity : CMOS technology provides excellent noise rejection
- Temperature stability : -40°C to +85°C operating range
- Retriggerable capability : Output pulse can be extended by retriggering inputs
Limitations :
- Maximum frequency limitation : 8MHz typical operating frequency
- External timing components required : RC networks needed for timing control
- Propagation delays : 60ns typical from trigger to output
- Limited output current : 1.6mA source/3.2mA sink capability
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Timing Accuracy Issues :
- Problem : Poor timing accuracy due to capacitor leakage
- Solution : Use low-leakage ceramic or film capacitors (C0G/NP0 dielectric)
- Problem : Timing drift with temperature variations
- Solution : Implement temperature-compensated timing networks
False Triggering :
- Problem : Noise-induced false triggering on input lines
- Solution : Add Schmitt trigger input conditioning or RC filtering
- Problem : Power supply transients causing unwanted resets
- Solution : Implement proper power supply decoupling (0.1μF ceramic close to VCC)
Output Loading Problems :
- Problem : Excessive output loading affecting timing accuracy
- Solution : Buffer outputs when driving heavy loads (>10mA)
- Problem : Output ringing due to transmission line effects
- Solution : Use series termination resistors for long PCB traces
### Compatibility Issues with Other Components
TTL Interface Considerations :
- Direct TTL compatibility when operating at 5V supply
- May require pull-up resistors for proper TTL level translation
- Output drive capability sufficient for 2 TTL loads
Mixed-Signal Systems :
- Analog timing components affect overall system accuracy
- Digital switching noise can couple into sensitive analog circuits
- Separate analog and digital ground planes recommended
Microcontroller Integration :
- Compatible with most microcontroller I/O voltages (3.3V-5V)
- Watch for timing constraints in fast microcontroller systems
- Consider software debouncing as alternative for simple applications
### PCB Layout Recommendations
Power Supply Decoupling :
- Place 0.1μF ceramic capacitor within 5mm of VCC pin
- Additional 10μ
