2.5 V to 5.0 V Micropower, Precision Series Mode Voltage References# AD1585ART Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The AD1585ART is a precision, low-power shunt voltage reference commonly employed in:
Primary Applications:
- ADC/DAC Reference Circuits : Provides stable 2.5V reference voltage for 12-16 bit analog-to-digital and digital-to-analog converters
- Voltage Regulation : Serves as precision reference for linear regulators and switching power supplies
- Sensor Interface Circuits : Maintains accurate reference levels for bridge sensors, thermocouples, and RTD measurements
- Portable Instrumentation : Battery-powered devices requiring stable voltage references with minimal current consumption
Signal Chain Integration:
- Positioned between power supply and precision analog front-end
- Typically interfaces with operational amplifiers, comparators, and data converters
- Used in feedback networks for precision current sources and voltage regulators
### Industry Applications
Industrial Automation:
- PLC analog I/O modules requiring ±0.1% accuracy
- Process control systems (4-20mA transmitters)
- Motor drive control circuits
- Temperature monitoring and control systems
Medical Electronics:
- Portable patient monitoring equipment
- Blood glucose meters and diagnostic devices
- Medical imaging system analog front-ends
- Wearable health monitoring sensors
Communications Infrastructure:
- Base station power management
- RF power amplifier bias circuits
- Network interface card analog sections
- Test and measurement equipment
Consumer Electronics:
- High-end audio equipment (DAC references)
- Digital multimeters and oscilloscopes
- Automotive infotainment systems
- Camera and imaging systems
### Practical Advantages and Limitations
Advantages:
- Low Temperature Coefficient : 50 ppm/°C maximum ensures stability across operating range
- Low Supply Current : 100 μA maximum enables battery-operated applications
- High Initial Accuracy : ±0.1% provides precision without calibration
- Small Form Factor : SOT-23-3 package saves board space
- Wide Operating Range : -40°C to +125°C suits industrial environments
- Long-Term Stability : 50 ppm/1000 hrs typical ensures consistent performance
Limitations:
- Fixed Output Voltage : 2.5V only (no adjustable versions available)
- Shunt Configuration : Requires external series resistor, increasing component count
- Limited Current Sink Capability : 10 mA maximum limits drive capability
- Temperature Hysteresis : ~30 ppm typical after temperature cycling
- Load Regulation : 0.4 mV/mA requires careful load current management
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Current Setting Resistor Calculation:
- Pitfall : Incorrect Rs value causing inadequate bias current or excessive power dissipation
- Solution : Calculate Rs = (Vsup - Vref) / (Iload + Iref_min) where Iref_min = 100 μA
- Example : For Vsup = 5V, Iload = 1mA → Rs = (5-2.5)/(0.001+0.0001) = 2.27 kΩ
Thermal Management:
- Pitfall : Excessive power dissipation in small package affecting accuracy
- Solution : Limit power dissipation to <100 mW, use thermal vias for SOT-23 package
- Implementation : Pdis = (Vsup - Vref) × (Iref + Iload)
Noise Performance Optimization:
- Pitfall : Inadequate bypassing causing noise injection into sensitive analog circuits
- Solution : Use 1-10 μF tantalum or ceramic capacitor close to reference output
- Additional : Add 0.1 μF ceramic capacitor in parallel for high-frequency noise suppression
### Compatibility
