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AS5043ASST

Programmable 360° Magnetic Angle Encoder with Absolute SSI and Analog Outputs

austriamicrosystems AG 

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

lid 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.

a 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

v output can be buffered to allow output currents up to hundred milliamperes or more.

Furthermore, the OPAMP can be configured as constant current source.

ill 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

t 0…100% range allows easy replacement of potentiometers. Due to the nature of rail-to-rail outputs, the linearity will

G s 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

A t 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.

s en 11.1 Analog Output Voltage Modes

m t 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.

a n 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.

co 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 =

l internal 2x gain, see Figure 14)

a Figure 8: Analog Output, Full Scale Mode (shown for 360°mode)

ic Vref

100%

n analog

h output

voltage

Tec 0V 0°

90°

180°

270°

angle

360°

Note: For simplification, Figure 8 describes

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)

Note: Figure 8 and are shown for 360°

operation. See Table 5 (page 16) for further

angular range programming options.

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Revision 1.80

10 – 36

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