MA710 – 12-BIT, DIGITAL ANGLE SENSOR WITH ABZ & UVW OUTPUTS

MA710 Rev. 1.0

www.MonolithicPower.com

11

9/27/2017

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© 2017 MPS. All Rights Reserved.

Figure 4: End-of-Shaft Mounting

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 MA710 can be adjusted

to compensate for this effect and recover the

linear relation between the mechanical angle

and the sensor output. With multiple pole pair

magnets,

the

MA710

indicates

multiple

rotations for each mechanical turn.

Figure 5: Side-Shaft Mounting

Electrical Mounting and Power Supply

Decoupling

It is recommended to place a 1µF decoupling

capacitor close to the sensor with a low

impedance path to GND (see Figure 6).

Figure 6: Connection for Supply Decoupling

In general, the MagAlpha works well with or

without the exposed pad connected to anything.

For optimum conditions (electrically, thermally,

and mechanically), it is recommended that the

exposed pad be connected to ground.

Serial Interface

The sensor supports the SPI serial interface for

angle

reading

and

register

programming.

Alternatively, the SSI bus can be used for angle

reading (programming

through SSI

is not

supported).

SPI

SPI

is

a

4-wire,

synchronous,

serial

communication

interface.

The

MagAlpha

supports SPI Mode 3 and Mode 0 (see Table 1

and Table 2). The SPI Mode (0 or 3) is detected

automatically by the sensor and therefore does

not require any action from the user. The

maximum clock rate supported on SPI is

25MHz. There is no minimum clock rate. Note

that real-life data rates depend on the PCB

layout quality and signal trace length. See

Figure 7 and Table 3 for SPI timing.

All commands to the MagAlpha (whether for

writing or reading register content) must be

transferred through the SPI MOSI pin and must

be 16-bit long. See the SPI Communication

section on page 13 for details.

Table 1: SPI Specification

Mode 0

Mode 3

SCLK idle state

Low

High

Data capture

On SCLK rising edge

Data transmission

On SCLK falling edge

CS idle state

High

Data order

MSB first

Table 2: SPI Standard

Mode 0

Mode 3

CPOL

0

1

CPHA

0

1

Data Order (DORD)

0 (MSB first)

Exposed pad

MOSI

MISO

CS

SCLK

MA710

1 mF

3.3 V

SSD

SSCK

MGL MGH

A

B

Z

PWM

GND

VDD

TEST