AK8975 Datasheet, PDF (5/34 Pages) Asahi Kasei Microsystems – 3-axis Electronic Compass

[AK8975/C]
4.1. Block Diagram
4. Circuit Configuration
3-axis
Hall
sen sor
MUX
Chopper
SW
Pre-
AMP
IntegratorˍADC
Magnetic source
HE -Driv e
Voltage
Reference
OSC1
Timin g
Control
CAD0
CAD1 _{TST1 TST2 RSV}
TST6
POR
VSS VDD VID
Interface,
Logic
& Register
FUSE ROM
SCL/SK
SDA/SI
CSB
SO
DRDY
4.2. Block Function

Block
Function
3-axis Hall sensor _{Monolithic Hall elements.}
MUX
Multiplexer for selecting Hall elements.
Chopper SW
Performs chopping.
HE-Drive
Magnetic sensor drive circuit for constant-current driving of sensor
Pre-AMP
Variable-gain differential amplifier used to amplify the magnetic sensor signal.
Integrator & ADC _{Integrates and amplifies pre-AMP output and performs analog-to-digital}
conversion.
OSC1
Generates an operating clock for sensor measurement.
6.144MHz(typ.)
POR
Power On Reset circuit. Generates reset signal on rising edge of VDD.
Interface Logic
Exchanges data with an external CPU.
DRDY pin indicates sensor measurement end and data is ready to be read.
I²C bus interface using two pins, namely, SCL and SDA. Standard mode and Fast
mode are supported. The low-voltage specification can be supported by applying
1.65V to the VID pin.
4-wire SPI is also supported by SK, SI, SO and CSB pins.
4-wire SPI works in VID pin voltage down to 1.65V, too.
Timing Control
Generates a timing signal required for internal operation from a clock generated
by the OSC1.
Magnetic Source _{Generates magnetic field for self test of magnetic sensor.}
FUSE ROM
Fuse for adjustment
MS1187-E-02
-5-
2010/05