1.8 V Precision Voltage Reference# ADR318ARJREEL Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The ADR318ARJREEL is a precision 1.8V voltage reference IC designed for applications requiring high accuracy and stability. Typical use cases include:
- High-Precision Data Acquisition Systems : Used as reference voltage for 16-18 bit ADCs in measurement equipment
- Industrial Process Control : Provides stable reference for sensor signal conditioning circuits
- Medical Instrumentation : Ensures accurate voltage references in patient monitoring devices
- Test and Measurement Equipment : Maintains calibration accuracy in laboratory instruments
- Portable Battery-Powered Devices : Low power consumption makes it suitable for handheld instruments
### Industry Applications
Industrial Automation :
- PLC systems requiring stable voltage references
- Motor control feedback systems
- Temperature measurement circuits
Communications Infrastructure :
- Base station power management
- Network analyzer calibration
- RF power measurement systems
Medical Electronics :
- Blood glucose monitors
- Portable ECG devices
- Digital thermometers
Automotive Systems :
- Engine control units (where temperature stability is critical)
- Battery management systems
- Sensor interface modules
### Practical Advantages and Limitations
Advantages :
- High Initial Accuracy : ±0.1% maximum initial error
- Excellent Temperature Stability : 8ppm/°C maximum temperature coefficient
- Low Noise Performance : Typically 4μVp-p (0.1Hz to 10Hz)
- Low Power Consumption : 120μA maximum supply current
- Small Package : SOT-23-6 package saves board space
- Wide Operating Range : -40°C to +125°C temperature range
Limitations :
- Fixed Output Voltage : 1.8V output only (not adjustable)
- Limited Output Current : 10mA maximum output current
- Sensitivity to Load Capacitance : Requires careful capacitive load management
- Cost Consideration : Higher cost compared to general-purpose references
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Improper Decoupling
- Issue : Inadequate decoupling leads to noise and instability
- Solution : Use 1μF ceramic capacitor at input and 10μF tantalum at output
- Implementation : Place capacitors within 5mm of device pins
Pitfall 2: Thermal Management
- Issue : Self-heating affects accuracy in high-temperature environments
- Solution : Ensure adequate PCB copper area for heat dissipation
- Implementation : Use thermal vias under the package for improved heat transfer
Pitfall 3: Load Regulation Problems
- Issue : Dynamic load changes cause output voltage variations
- Solution : Add local buffering for high-current applications
- Implementation : Use low-noise op-amp as buffer for loads >5mA
### Compatibility Issues with Other Components
ADC Interface Considerations :
- Compatible ADCs : Works well with ADI's AD7685, AD7792 series
- Timing Requirements : Allow 500ms warm-up time after power-on
- Noise Coupling : Keep reference output traces away from digital signals
Amplifier Compatibility :
- Recommended Op-Amps : AD8628, AD8638 for low-noise applications
- Input Range Matching : Ensure amplifier input common-mode range includes 1.8V
- Power Supply Sequencing : Reference should stabilize before amplifier power-up
Digital Interface Considerations :
- I²C/SPI Isolation : Use separate ground planes for analog and digital sections
- Clock Noise : Shield reference circuitry from high-frequency clock signals
### PCB Layout Recommendations
Power Supply Routing :
- Use star-point grounding for reference and analog circuitry
- Implement separate
