1. Overview & Functionality

️· What it is: The AS5043 is a magnetic rotary encoder. It detects the angle of a rotating magnet.
️· Key Features:
- Analog and Digital Outputs: Provides both an analog voltage proportional to the angle and a digital serial data stream.
- Daisy Chain Capability: Multiple AS5043s can be connected in series for extended angle measurement.
- Programmable Angular Range: The angular range is adjustable (360°, 180°, 90°, 45°) through programming.
- OTP Options: One-Time Programmable features allow configuration of analog output ranges and other parameters.

2. Electrical Connections and Signals

️· Supply Voltage (VDD5V): Typically 3.0V to 5.5V.
️· Analog Output (Vout): Provides a voltage proportional to the angle. Can be ratiometric to VDD5V or an external reference (DACref).
- OTP Options:
■ Full scale: 0% - 100% of Vref.
■ Clamped: 10% - 90% of Vref. Allows for failure detection.
️· Digital Outputs:
- DO (Data Output): Serial data stream representing the angle.
- PROG (Program Input): Used for daisy chaining and programming.
️· MODE Pin: Configures the encoder's operation mode:
- Slow Mode (Pin MODE = 0): 2.61 kHz sampling rate, <0.03° rms transition noise, 384µs propagation delay.
- Fast Mode (Pin MODE = 1): 10.42 kHz sampling rate, <0.06° rms transition noise, 96µs propagation delay.

3. Daisy Chain Mode

️· Functionality: Allows connecting multiple AS5043 encoders in series.
️· Hardware: Connect DO of one encoder to the PROG input of the next. RC filter (100Ω R, 1nF C) between PROG/DO pins.
️· Data Length: Increases with each encoder (n * (16+1) bits).
️· Timing: The last data bit of the first device (Parity) is followed by a dummy bit and the first data bit of the second device (D9).

4. Analog Output Details

️· Reference Voltage: Can be internal (VDD5V/2) or external (DACref).
️· Output Range: Programmable (full-scale rail-to-rail, or clamped 10%-90%).
️· Current Capability: Normal operation: ±1mA. Short-circuit current: up to 66mA.
️· DACout Pin: Provides direct access to the DAC output.
️· OPAMP Buffer: Allows for user-configurable options (voltage ranges, response). Can be configured as a constant current source.

5. Key Parameters Table (Summary)

Parameter	Slow Mode	Fast Mode
Sampling Rate	2.61 kHz (383µs)	10.42 kHz (95.9µs)
Transition Noise (1 sigma)	≤ 0.03° rms	≤ 0.06° rms
Propagation Delay	384µs	96µs
Startup Time	20ms	80ms

In essence, the AS5043 is a versatile magnetic rotary encoder suitable for various applications requiring accurate angle measurement and flexible configuration.