DA6501.001
27 October 2008
APPLICATION INFORMATION
+
C
VDD
VDD
GND
R
1
SENSOR
PI
Input MUX
P
P
T
Control
ADC
Dig.
filter
MCLK
EOC
SDA
NI
T
I C
Serial
Interface
2
SCL
XCLR
R
3
COMMON
R
4
P
T
R
2
T
MAS9185
MAS6501
GND
GND
Figure 3.
Resistive sensor connection circuit
Together with a resistive pressure sensor,
MAS6501 can be used in pressure measurement
applications. Control can be performed with a micro-
2
controller through the I C serial interface.
The sensor is connected between the power supply
voltage (VDD) and MAS6501 signal ground
(COMMON) which can be internally (switch inside of
MAS6501) connected to ground (GND). Sensor
output is read as a differential signal through PI
(positive input) and NI (negative input) to the
∆Σ
converter in MAS6501.
In the pressure measurement mode, the switches
marked “P” are closed and the sensor output is fed
through to the ADC. In the temperature
measurement mode, the switches marked “T” are
closed and the voltage at the ADC input is
determined by the internal resistor array and the
temperature-dependent resistance of the sensor. In
this configuration the sensor bridge is connected as
part of single four resistor bridge circuit where other
four resistors (R1, R2, R3, R4) are inside the IC.
To guarantee conversion accuracy a supply voltage
decoupling capacitor of 4.7
µF
or more should be
placed between VDD and GND of MAS6501 (see
C
VDD
in figure 3).
9 (16)
MAS [ MICRO ANALOG SYSTEMS ]
