CMOS, Low-Voltage, 2-Wire Serially-Controlled, Matrix Switches# ADG729BRU Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The ADG729BRU is a monolithic CMOS device containing two independently selectable single-pole/double-throw (SPDT) switches. Typical applications include:
Signal Routing Systems
- Audio/video signal switching in multimedia systems
- Data acquisition channel selection
- Instrumentation input multiplexing
- Communication system signal path switching
Battery-Powered Equipment
- Portable medical devices (patient monitoring, diagnostic equipment)
- Handheld test and measurement instruments
- Mobile communication devices
- Portable data loggers
Automated Test Equipment
- Multi-channel test system switching
- Calibration system signal routing
- Production test fixture switching matrices
### Industry Applications
Industrial Automation
- Process control system I/O multiplexing
- PLC input channel selection
- Sensor array scanning systems
- Factory automation signal routing
Medical Electronics
- Patient monitoring equipment
- Diagnostic imaging systems
- Laboratory instrumentation
- Medical data acquisition systems
Communications Infrastructure
- Base station signal routing
- Network switching equipment
- Telecom test instrumentation
- Wireless infrastructure monitoring
Consumer Electronics
- High-end audio/video receivers
- Professional recording equipment
- Gaming console peripheral switching
- Home automation systems
### Practical Advantages and Limitations
Advantages:
- Low Power Consumption : Typical supply current of 0.01 μA
- Fast Switching : tON = 35 ns maximum, tOFF = 20 ns maximum
- Low On-Resistance : 4 Ω maximum at 25°C
- 2.7 V to 5.5 V Single Supply Operation
- I²C Compatible Interface : Supports 400 kHz operation
- Small Package : 16-lead TSSOP for space-constrained applications
Limitations:
- Signal Range : Limited to supply rails (VSS to VDD)
- Current Handling : Maximum continuous current of 30 mA per channel
- ESD Sensitivity : Requires proper handling (2 kV HBM)
- Temperature Range : Commercial grade (0°C to +70°C) limits high-temperature applications
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Power Supply Sequencing
- Pitfall : Applying digital signals before power supplies can cause latch-up
- Solution : Implement proper power sequencing with voltage supervisors
Signal Integrity Issues
- Pitfall : High-frequency signal degradation due to parasitic capacitance
- Solution : Use proper termination and keep trace lengths short
- Pitfall : Crosstalk between adjacent channels
- Solution : Implement ground shielding between critical signal paths
Digital Interface Problems
- Pitfall : I²C bus timing violations causing communication errors
- Solution : Ensure proper pull-up resistors and adhere to timing specifications
- Pitfall : Address conflicts in multi-device systems
- Solution : Carefully plan device addressing scheme
### Compatibility Issues with Other Components
Digital Interface Compatibility
- Compatible with standard I²C bus (100 kHz and 400 kHz)
- Requires 3.3V or 5V logic levels for control signals
- May need level translation when interfacing with 1.8V systems
Analog Signal Compatibility
- Works with signals from VSS to VDD
- Compatible with op-amps having rail-to-rail output capability
- May require buffering for high-impedance sources
Power Supply Considerations
- Compatible with standard LDO regulators
- Requires clean power supplies with proper decoupling
- Watch for supply voltage tolerance stack-up in multi-supply systems
### PCB Layout Recommendations
Power Supply Layout
- Place 0.1 μF decoupling capacitors within 5 mm of VDD pins
- Use separate ground planes for
