Magnetoresistive angle sensors
KMA200
Single package angle sensor system with on-chip diagnostics
The KMA200 is a pre-aligned, ready-to-use sensor system. It consists
of a magnetoresistive element containing two independent MR sensor
bridges and a signal conditioning IC in a special multi-chip package.
Over voltage and reversed polarity protection are both incorporated
into the device, as is temperature supervision.
KMA200 key features
• Programmable angle range (max. 180°)
• 4 analog and 2 digital output modes selectable
• 5 V supply
• Ratiometric analog output
• Reverse supply voltage protection up to 16.5 V
• Over voltage protection up to 26.5 V
• Over voltage maximum 32 V (for 400 ms)
• EEPROM (user programmable)
Magneto Resistive Element
Angle Sensor Chip
Thin Film Technology
• On-line diagnosis of all main functional blocks
• Ambient temperature range – 40 °C to + 160 °C
KMA200 key specifications
Signal Processing
Max. deviation from ideal line
at one point calibration
1.65 degree
Linearity error step of 1 degree
Repeatability
0.1 degree
0.1 degree
Resolution of analog output signal
Temperature drift of analog output
Measurement update rate
0.04 degree
0.64°max @ -25...+125°C
4 kHz
The KMA200 sensor system
A self-monitoring function supervises the blocks of the sensor system
during normal operation, automatically detecting failures in any part
of the sensor system and quickly indicats such a diagnosis error to the
connected higher-level system. User programmability is achieved via
an SPI with all data stored permanently in on-chip EEPROM, allowing
specific adjustments of the angular range, zero point and clamping level
to be set. Additionally, the device can be programmed to work either in
analog or digital (SPI) output modes.
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Analog output voltage with positive slope
MR SENSOR
SIGNAL CONDITIONING ELECTRONICS
The Magnetoresistive principle
INPUT
STAGE
OUTPUT
STAGE
µC
MR sensors use magnetic fields to conduct measurement information
between physical value and sensor. This contactless principle allows
isolation of all rotating components, making the entire sensing system
robust with respect to pollution and mechanical degradation. Another
characteristic is that MR sensors evaluate the direction of the magnetic
field and not the field strength: the field strength is not important as
long as it is above a certain operational minimum.
EEPROM/
RAM
TEMPERATURE
SENSOR
OSCILLATOR
ONLINE DIAGNOSIS
bra160
KMA200 single package solution
As a result, MR-based systems using the KMZ41 or KMZ43T can
tolerate variations in field strength caused by ageing, mechanical
fluctuations or temperature sensitivity of the magnet.
