AU6020
High-precision RTD-to-digital converter with automatic lead compensation, supporting 2/3/4-wire configurations.
Product Overview
Description
The AU6020 is a 24-bit RTD-to-digital converter designed for precision temperature measurement applications. It supports 2-wire, 3-wire, and 4-wire RTD configurations with automatic lead resistance compensation.
With integrated excitation current sources and programmable gain amplifier, the AU6020 achieves ±0.1°C accuracy for Pt100 and Pt1000 RTDs. The device includes fault detection for open and short circuit conditions.
The SPI interface provides fast data access and configuration. The AU6020 operates from a single 3.3V supply and is available in a compact TSSOP-16 package with industrial temperature range.
Product Series
AU
Primary Application
Industrial temperature sensing
Key Features
- 24-bit resolution ADC
- Automatic lead compensation
- 2/3/4-wire RTD support
- Integrated excitation current
- Fault detection
- Single 3.3V supply
Specifications
| Resolution | 24-bit |
|---|---|
| Input Type | 2/3/4-wire RTD |
| Accuracy | ±0.1°C (Pt100) |
| Conversion Rate | Up to 100 SPS |
| Interface | SPI |
| Package | TSSOP-16 |
Applications
Industrial temperature sensing
Industrial automation and control
HVAC systems
Electronic system design
Process control
Industrial automation and control
Medical equipment
Medical electronics
Environmental monitoring
Electronic system design
FAE Expert Insights
"The AU6020 is an excellent RTD interface solution that I've used in multiple industrial temperature monitoring systems. The automatic lead compensation works very well - I've verified accuracy better than ±0.1°C in 3-wire configurations. The fault detection feature is valuable for industrial applications, detecting open and short conditions quickly. One important tip: use the recommended input filtering shown in the datasheet to reject 50/60Hz interference. The SPI interface is straightforward to implement. Overall, a cost-effective alternative to more expensive industrial RTD converters."
Excellent RTD interface with automatic lead compensation and fault detection
— Michael Zhang, BeiLuo
Frequently Asked Questions
What RTD types are supported by AU6020?
The AU6020 supports all standard platinum RTD types including Pt100, Pt1000, Pt500, and Pt200 with α = 0.00385 or 0.003916. The device uses the standard Callendar-Van Dusen equation for linearization. For nickel or copper RTDs, custom coefficients can be programmed through the SPI interface. The excitation current is programmable (100μA to 1mA) to optimize for different RTD types and reduce self-heating effects.
AU6020 supports Pt100/Pt1000 and other platinum RTDs with programmable excitation.
How do I minimize measurement noise?
To minimize noise in RTD measurements: (1) Use the recommended RC filter at the ADC input (typically 1kΩ + 100nF); (2) Enable the internal digital filter with appropriate settling time; (3) Use lower excitation current to reduce self-heating (trade-off with SNR); (4) Ensure proper PCB layout with analog ground plane; (5) Keep sensor leads away from switching power circuits; (6) Use shielded cables for long sensor runs. The AU6020's 24-bit resolution with noise-free bits typically exceeds 20 bits in practical applications.
Use input filtering, digital filtering, and proper PCB layout for best noise performance.
What is the conversion rate and resolution trade-off?
The AU6020 supports programmable conversion rates from 1 SPS to 100 SPS (samples per second). Lower rates provide better noise performance and higher effective resolution through digital filtering. Higher rates enable faster response times for dynamic measurements. At 1 SPS, the device achieves the lowest noise and highest resolution (up to 24 noise-free bits). At 100 SPS, the resolution is typically 18-20 bits. For most industrial temperature monitoring applications, 10-20 SPS provides a good balance of response time and accuracy.
Use 10-20 SPS for best balance; lower for higher resolution, higher for faster response.
How does lead resistance compensation work?
The AU6020 provides automatic lead resistance compensation: (1) 3-wire configuration - the device measures lead resistance and subtracts it from the measurement; (2) 4-wire configuration - eliminates lead resistance entirely through Kelvin connection; (3) 2-wire configuration - requires calibration to compensate for known lead resistance. For best accuracy, use 3-wire or 4-wire configurations. The AU6020 supports all three configurations with automatic detection and compensation.
Use 3-wire or 4-wire for best accuracy; 2-wire requires calibration.
What calibration options are available?
The AU6020 supports both factory calibration and user calibration: (1) Factory calibration - each device is calibrated at the factory and stored in OTP memory; (2) User calibration - perform offset and gain calibration using known reference points; (3) System calibration - calibrate with your specific sensor for highest accuracy; (4) Temperature calibration - compensate for temperature drift if operating over wide temperature range. For highest accuracy, perform system calibration at the operating temperature. The device provides registers for storing calibration coefficients.
Use factory calibration for standard accuracy; system calibration for highest accuracy.