aduc7062 Analog Devices, Inc., aduc7062 Datasheet - Page 49

• Manufacturer Part Number: aduc7062
• Description: Low-power, Precision Analog Microcontroller, Dual ?-? Adcs, Flash/ee, Arm7tdmi
• Manufacturer: Analog Devices, Inc.

Preliminary Technical Data
EXAMPLE APPLICATION CIRCUITS
Figure 12 shows a simple bridge sensor interface to the ADuC706x
including the RC filters on the analog input channels. Notice
that the sense lines from the bridge (connecting to the reference
inputs) are wired separately from the excitation lines (going to
VDD and ground). This results in a total of six wires going to
the bridge. This 6-wire connection scheme is a feature of most
off-the-shelf bridge transducers (such as load cells) that helps to
minimize errors that would otherwise result from wire
impedances.
In Figure 13, AD592 is an external temperature sensor used to
measure the thermocouples cold junction and its output is
RTD
ADR280
AD592
Figure 13. Example of a Thermocouple Interface Circuit
Figure 14. Example of an RTD Interface Circuit
Figure 12. Bridge Interface Circuit
+2.5V
Rev. PrA | Page 49 of 100
VDD
REFIN+
AIN0
AIN1
REFIN–
GND
AIN0
AIN1
AIN4
REFIN+
REFIN–
IEXC1
AIN0
AIN1
REFIN+
REFIN–
ADuC7060/
ADuC7061/
ADuC7062
ADuC7060/
ADuC7061/
ADuC7062
ADuC7060/
ADuC7061/
ADuC7062
connected to the auxiliary channel. ADR280 is an external 1.2 V
reference part—alternatively, the internal reference can be used
also. Here, the thermocouple is connected to the primary ADC
as a differential input to ADC0/ADC1. Note the resistor
between REFIN+ and ADC1 to bias the ADC inputs above
100 mV.
Figure 14 shows a simple 4-wire RTD interface circuit. As with
the bridge transducer implementation in Figure 12, if a power
supply and a serial connection to the outside world are added,
then Figure 14 represents a complete system.
UART
GPIO
ETC.
UART
GPIO
UART
ETC.
VDD
GND
GPIO
SPI
I
ETC.
VDD
GND
2
SPI
I
SPI
C
2
I
2
C
C
+2.5V
ADuC7060/ADuC7061/ADuC7062
+2.5V