A1335
Contactless 0° to 360° angle sensor with 12-bit resolution and analog/PWM output for automotive and industrial applic...
Product Overview
Description
The A1335 is a 360° contactless high-resolution programmable angle position sensor. It is designed for digital systems, but its output is available as either PWM or analog signal. The device is ideal for automotive applications requiring high-speed 360° angle measurements, such as electronic power steering (EPS), transmission, and throttle systems.
The A1335 uses a Hall-effect sensing technology that provides contactless angle measurement with excellent accuracy and reliability. The device features on-chip EEPROM for programming calibration parameters, allowing customization for specific applications. The 12-bit angular resolution (0.087°) provides precise position information for control systems.
The sensor includes advanced features such as linearization for improved accuracy, programmable angle range, and diagnostic capabilities. The analog output provides ratiometric voltage proportional to angle, while the PWM output offers noise-immune digital interface. The device operates from -40°C to 150°C, meeting AEC-Q100 Grade 0 requirements.
Product Series
A
Primary Application
Electronic power steering
Key Features
- Contactless 360° angle measurement
- 12-bit resolution (0.087°)
- Programmable via EEPROM
- Linearization for improved accuracy
- Analog ratiometric or PWM output
- On-chip diagnostics
- AEC-Q100 Grade 0 qualified
- Compact TSSOP-8 package
Specifications
| Measurement Range | 0° to 360° |
|---|---|
| Resolution | 12-bit (0.087°) |
| Accuracy | ±1° typical |
| Output | Analog ratiometric or PWM |
| Supply Voltage | 4.5V to 5.5V |
| Bandwidth | 15kHz |
| Temperature Range | -40°C to +150°C |
| Package | TSSOP-8, SOIC-8 |
Applications
Electronic power steering
Electronic system design
Transmission position sensing
Electronic system design
Throttle position sensing
Electronic system design
Pedal position sensing
Electronic system design
Valve position control
Industrial automation and control
Robotic joint position
Electronic system design
FAE Expert Insights
"The A1335 is my recommended solution for contactless angle sensing in automotive applications. The 12-bit resolution provides sufficient precision for most control systems, and the ±1° accuracy meets typical automotive requirements. The programmable EEPROM is a key feature - it allows customization of angle range, zero position, and linearization for specific applications. I've used it successfully in EPS systems where the contactless operation eliminates the wear issues of potentiometer-based sensors. Design considerations: Magnet alignment is critical for accuracy - use precision-machined mounts; The ratiometric output is ideal for automotive systems with varying supply voltage; Implement the diagnostic features for safety-critical applications. The AEC-Q100 Grade 0 qualification provides confidence for harsh automotive environments. For applications requiring higher accuracy, consider the AAS33001 with 14-bit resolution and ISO 26262 support."
Contactless operation eliminates wear; programmable EEPROM allows customization; AEC-Q100 qualified for automotive
— David Park, BeiLuo
Frequently Asked Questions
How do I calibrate the A1335 for my application?
The A1335 calibration process using on-chip EEPROM: Parameters to program - Zero angle offset: Sets the 0° position; Angle range: Full-scale angle (90°, 180°, 270°, 360°); Output polarity: Clockwise vs counterclockwise increasing; Linearization coefficients: 7-point lookup table for error correction. Programming procedure: 1) Connect to Allegro programming hardware or use in-system programming; 2) Measure actual angle with reference encoder; 3) Calculate offset and linearization values; 4) Program EEPROM with calculated values; 5) Verify accuracy after programming. Calibration benefits: Improves accuracy from ±2° to ±1° or better; Compensates for magnet misalignment; Adjusts for specific angle range requirements. End-of-line calibration is recommended for production to achieve best accuracy. Allegro provides software tools and programming hardware for calibration.
Program zero offset and angle range; implement 7-point linearization for best accuracy; use end-of-line calibration.
What magnet configuration is recommended for A1335?
Recommended magnet configurations for A1335: Magnet type - Diametrically magnetized disc magnet; Material: Neodymium (NdFeB) for best performance; Temperature grade: Choose based on operating temperature. Magnet dimensions - Diameter: 6-10mm typical; Thickness: 2-5mm; Larger magnets provide stronger fields and better noise immunity. Air gap - Typical: 1-3mm between magnet and sensor; Smaller gap: Stronger field, better noise immunity; Larger gap: More mounting tolerance, lower field strength. Field strength target - 300-800 Gauss at sensor location; Minimum 200G for reliable operation; Maximum 1000G to avoid saturation. Mounting considerations - Use non-ferrous shaft (aluminum, brass, plastic); Ensure concentric rotation to minimize wobble; Consider magnetic shield if external fields present. Allegro provides magnet selection guidelines and can recommend specific part numbers for your application.
Use diametric NdFeB magnet 6-10mm diameter; maintain 1-3mm air gap; target 300-800G field strength.
What is the recommended magnet for this sensor?
Magnet selection guidelines: Use diametrically magnetized disc magnets for angle sensors. Neodymium (NdFeB) provides best performance with high field strength. Target 300-800 Gauss field strength at the sensor location. Magnet diameter of 6-10mm typical with 2-5mm thickness. Maintain 1-3mm air gap between magnet and sensor. Use non-ferrous shafts (aluminum, brass) to avoid field distortion. Consider temperature grade based on operating environment.
Use diametric NdFeB magnet, 6-10mm diameter, 1-3mm air gap, target 300-800G.
How do I calibrate the sensor for best accuracy?
Calibration procedure: Use the on-chip EEPROM to program calibration parameters. Measure actual position with a reference encoder at multiple points. Calculate offset error at zero position. Determine gain error across the measurement range. Apply 7-point linearization for best accuracy. End-of-line calibration is recommended for production. Typical improvement: ±2° to ±1° or better after calibration. Allegro provides software tools for calibration.
Use EEPROM programming; implement offset, gain, and linearization calibration.
What is the sensor bandwidth and response time?
The sensor provides 15kHz bandwidth suitable for most automotive and industrial applications. Response time is approximately 100μs from input change to stable output. For faster applications, consider sensors with > 100kHz bandwidth. The analog output provides continuous position information, while PWM output updates at the PWM frequency. Filter the output with RC filter (1-10kHz cutoff) to reduce noise if needed.
15kHz bandwidth suitable for most applications; filter output if noise is concern.