CMOS, 2.5ohm Low-Voltage, 8-/16-Channel Multiplexers# ADG707BRU Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The ADG707BRU is a CMOS 8-channel analog multiplexer designed for precision signal routing applications. Key use cases include:
Signal Routing Systems
- Test and Measurement Equipment : Automated channel switching in multimeters, data acquisition systems, and oscilloscopes
- Medical Instrumentation : Patient monitoring systems requiring multiple sensor inputs
- Industrial Control Systems : Multi-point temperature, pressure, and flow monitoring
Data Acquisition Systems
- Multi-sensor Interfaces : Switching between multiple analog sensors (temperature, pressure, strain gauges)
- Battery Monitoring : Sequential measurement of individual cell voltages in battery packs
- Process Control : Scanning multiple process variables in industrial automation
Audio/Video Switching
- Professional Audio Consoles : Input channel selection in mixing consoles
- Video Distribution Systems : Source selection in multi-input display systems
### Industry Applications
Automotive Electronics
- Battery Management Systems (BMS) : Monitoring individual cell voltages in EV/HEV batteries
- Sensor Arrays : Switching between multiple temperature, pressure, and position sensors
- Diagnostic Systems : Multiplexing diagnostic signals for OBD-II compliance
Industrial Automation
- PLC Systems : Analog input module channel selection
- Process Control : Multi-point measurement in chemical and manufacturing processes
- Motor Control : Current and voltage monitoring in drive systems
Medical Equipment
- Patient Monitoring : ECG, EEG, and other biomedical signal routing
- Diagnostic Instruments : Multi-channel signal acquisition in medical imaging
- Laboratory Equipment : Automated test system channel switching
Communications
- Base Station Equipment : RF signal routing in wireless infrastructure
- Network Monitoring : Signal multiplexing in telecom test equipment
### Practical Advantages and Limitations
Advantages
- Low Power Consumption : Typical supply current of 1μA enables battery-operated applications
- High Integration : Single-chip solution replaces multiple discrete switches
- Excellent Signal Integrity : Low on-resistance (45Ω typical) and flatness
- Fast Switching : 150ns turn-on time supports high-speed systems
- Break-Before-Make Switching : Prevents signal shorting during channel changes
Limitations
- Analog Signal Range : Limited to supply rails (VSS to VDD)
- Channel-to-Channel Crosstalk : -80dB at 1MHz may affect sensitive measurements
- On-Resistance Variation : ±15Ω variation across channels requires calibration in precision applications
- Charge Injection : 10pC typical may affect sample-and-hold circuits
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Power Supply Sequencing
- Pitfall : Applying analog signals before power supplies can cause latch-up
- Solution : Implement proper power sequencing with reset circuits
- Implementation : Use power supervisors to ensure VDD > VSS before signal application
Signal Level Management
- Pitfall : Exceeding absolute maximum ratings (-VSS - 0.3V to VDD + 0.3V)
- Solution : Add clamping diodes or series resistors for protection
- Implementation : Use Schottky diodes to supply rails for overvoltage protection
Switching Artifacts
- Pitfall : Glitches during channel switching affect downstream circuits
- Solution : Implement blanking periods in control logic
- Implementation : Add 200ns settling time after channel selection
### Compatibility Issues with Other Components
ADC Interface Considerations
- Issue : Charge injection affects sampling accuracy
- Solution : Use low-input-bias-current op-amps as buffers
- Recommended Components : AD8628, OPA376 for precision applications
Digital Control Interface
- Issue : 3V logic compatibility
