[AK8975/C]
4.
Circuit Configuration
4.1. Block
Diagram
3-axis
Hall
sensor
MUX
SDA/SI
DRDY
Chopper
SW
HE-Drive
Pre-
AMP
Integrator
&
ADC
Interface,
Logic
& Register
SCL/SK
VDD
Voltage
Reference
Timing
Control
VID
SO
OSC1
CSB
Magnetic source
CAD0
VSS
POR
FUSE ROM
CAD1
TST1
TST2
RSV
TST6
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.
I
2
C 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