1. Overview & Purpose

️· What it is: The ATS625 is a gear tooth sensor designed for accurate and reliable detection of gear rotation. It's specifically engineered to deal with challenges like varying air gaps and installation offsets.
️· Key Features: Automatic Gain Control (AGC), Dynamic Offset Adjustment, and continuous update of switchpoints.

2. Core Technologies & How They Work

️· Automatic Gain Control (AGC):
- What it does: Keeps the internal signal amplitude constant over a range of air gaps (distance between sensor and gear).
- Benefit: Eliminates performance variation due to changes in air gap.
️· Dynamic Offset Adjustment:
- What it does: Minimizes the effects of installation offsets (e.g., tilted sensor).
- How it works: Two DACs track the peaks of the signal, and these are used to establish switching thresholds.
️· Continuous Update of Switchpoints:
- What it is: Uses data from previous gear rotations to dynamically adjust the switching thresholds.
- Benefit: Provides immunity to target run-out (gear displacement) and transient mechanical events (e.g., backlash).
- How it works: The device uses the two previous voltage peaks to determine the next threshold.
️· Switchpoints:
- How it is determined: Determined dynamically as a percentage of the signal. The thresholds are 40% and 60% of the peak-to-peak signal.
- Low Hysteresis: The hysteresis is 20%, which ensures accurate and consistent switching.

3. Operation and Startup

️· Power-On State: Initially powers off with a high output signal (VOUT high).
️· Edge Synchronization: Uses the first two mechanical edges to synchronize with the target and rotation direction. The third edge determines proper synchronization.
️· Startup Scenarios: The initial behavior can vary depending on the target's position relative to the sensor at power-on. These variations are accounted for in the ATS625 operation.

4. Magnetic Profile and Evaluation

️· Importance: Creating a magnetic map of the gear and sensor system is essential for proper operation. This map shows the magnetic field strength versus air gap.
️· B_IN: The minimum magnetic flux density needed for reliable operation (B_IN) determines the maximum allowable air gap.
️· Figure 10: Shows a magnetic data map of the 60+2 reference target.
️· Figure 11: illustrates the relationship between B_IN and the maximum allowable air gap (AG).

5. Key Terminology & Concepts

️· Air Gap (AG): The distance between the sensor and the gear.
️· B_IN: Minimum required magnetic field strength for operation.
️· DAC (Digital-to-Analog Converter): Converts digital signals to analog voltage levels.
️· V_PROC: Processed signal representing the gear tooth position.
️· Hysteresis: The difference between the rising and falling threshold voltages. Lower hysteresis means more accurate switching.