MA300GQ-P Datasheet, PDF (6/18 Pages) MPS Industries, Inc. – Angular Sensor for 3-Phase Brushless Motor Commutation and Position Control with Side-Shaft Positioning Capability

MA300
Angular Sensor for 3-Phase Brushless Motor
Commutation and Position Control with Side-Shaft
Positioning Capability
5. Sensor – Magnet Mounting
The sensitive volume of the MA300 is confined in
a region less than 100µm wide and has multiple,
integrated Hall devices. This volume is located
both horizontally and vertically (with a precision
50µm in the center of the QFN package). The
sensor detects the angle of the magnetic field
projected in a plane parallel to the upper surface
of the package, making the only magnetic field
that matters, the in-plane component (X and Y
components) in the middle point of the package.
specifications (see Table 2). The straightforward
solution places the MA300 sensor on the rotation
axis of a permanent magnet, i.e., a cylinder
diametrically magnetized (see Figure 4).
If the end-of-shaft position is not available, the
sensor can be positioned away from the rotation
axis of a cylinder or ring magnet (see Figure 5). In
this case, the magnetic field angle is no longer
directly proportional to the mechanical angle. The
MA300 can be adjusted to compensate this effect
and recover the linear relation between the
mechanical angle and the sensor output. With
multiple pole pairs, the MA300 indicates multiple
rotations for each mechanical turn.
Figure 4: End-of-Shaft Mounting
This detection mode allows flexibility for the
design of an angular encoder. All the sensor
needs is the magnetic vector to lie essentially
within the sensor plane with its amplitude between
30mT and 150mT. Note that the MA300 works
with fields smaller than 30mT, but the linearity and
resolution performance may deviate from the
6. Power Supply Decoupling
For most applications, a single 100nF bypass
capacitor placed close to the supply pins
sufficiently decouples the MA300 from noise from
the power supply. If improved decoupling is
required, a larger capacitor (10 µF) can be added
in parallel with the 100nF capacitor, and/or a
resistor (10) can be added between the supply
line and the capacitor node.
In any case, make sure that the connection
between the MA300 ground and the power supply
ground has low impedance in order to avoid noise
transmitted from the ground.
Figure 5: Side-Shaft Mounting
VFLASH must be supplied only when flashing the
memory. Otherwise VFLASH can remain
unconnected or grounded (see Figure 6).
Monolithic Power Systems, Inc. | Gland, Switzerland | Tel: [phone] | [e-mail] | www.sensimatech.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2014 Monolithic Power Systems. All Rights
Reserved. MA700 Rev 1.0 September 2014
6