AS5043
Data Sheet – Analog Output
11 Analog Output
The analog output Vout provides an analog voltage that is proportional to the angle of the rotating magnet and ratiometric
to the supply voltage VDD5V (max.5.5V). It can source or sink currents up to ±1mA in normal operation (up to 66mA short
circuit current).
The analog output block consists of a digital angular range selector, a 10-bit Digital-to-Analog converter and an OPAMP
buffer stage (see Figure 14).
The digital range selector allows a preselection of the angular range for 360°,180°,90° or 45° (see Table 5). Fine-tuning of
the angular range can be accomplished by adjusting the gain of the OPAMP buffer stage.
The reference voltage for the Digital-to-Analog converter (DAC) can be taken internally from VDD5V / 2. In this mode, the
output voltage is ratiometric to the supply voltage.
Alternatively, an external DAC reference can be applied at pin DACref (#9). In this mode, the analog output is ratiometric
to the external reference voltage.
An on-chip diagnostic feature turns the analog output off in case of an error (broken supply or magnetic field out of range;
see Table 3).
The DAC output can be accessed directly at pin #10 DACout.
The addition of an OPAMP to the DAC output allows a variety of user configurable options, such as variable output
voltage ranges and variable output voltage versus angle response. By adding an external transistor, the analog voltage
output can be buffered to allow output currents up to hundred milliamperes or more.
Furthermore, the OPAMP can be configured as constant current source.
As an OTP option, the DAC can be configured to 2 different output ranges:
a) 0……100% VDACref. The reference point may be either taken from VDD5V/2 or from the external DACref input. The
0…100% range allows easy replacement of potentiometers. Due to the nature of rail-to-rail outputs, the linearity will
degrade at output voltages that are close to the supply rails.
b) 10…..90% VDACref. This range allows better linearity, as the OPAMP is not driven to the rails. Furthermore, this mode
allows failure detection, when the analog output voltage is outside of the normal operating range of 10…90%VDD, as in
the case of broken supply or when the magnetic field is out of range and the analog output is turned off.
11.1 Analog Output Voltage Modes
The Analog output voltage modes are programmable by OTP. Depending on the application, the analog output can be
selected as rail-to-rail output or as clamped output with 10%-90% VDD5V.
The output is ratiometric to the supply voltage (VDD5V), which can range from 3.0V to 5.5V. If the DAC reference is
switched to an external reference (pin DACref), the output is ratiometric to the external reference.
11.1.1 Full Scale Mode
*)
This output mode provides a ratiometric DAC output of (0% to 100%)x Vref , amplified by the OPAMP stage (default =
internal 2x gain, see Figure 14)
Figure 8: Analog Output, Full Scale Mode (shown for 360°mode)
Note: For simplification, Figure 8 describes
Vref
a linear output voltage from rail to rail (0V to
VDD). In practice, this is not feasible due to
saturation effects of the OPAMP output
driver transistors. The actual curve will be
rounded towards the supply rails (as
indicated in Figure 8)
100%
analog
output
voltage
Note: Figure 8 and are shown for 360°
operation. See Table 5 (page 16) for further
angular range programming options.
angle
0V
0°
90°
360°
180°
270°
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