Datasheet
+
ADC122S706
V
REF
CHA+
CHA-
GND
V
A
SCLK
D
OUTA
CSB
0.1 PF
10 PF
0.1 PF
+
10 PF
+5V
V
D
CHB-
CHB+
D
OUTB
DUAL
+5V
V
CM
OUT
+5V
GND
I
IN
I
OUT
2.5V
2.5V + 2.0V
I
IN
I
OUT
V
CM
OUT
+5V
GND
I
IN
I
OUT
2.5V
2.5V + 2.0V
I
IN
I
OUT
LTSR-15NPs
LM4132-2.0
ADC
ADC
Serial
Interface
2 k:
+
ADC122S706
V
REF
CHA+
CHA-
GND
V
A
SCLK
D
OUTA
0.1 PF
10 PF
0.1 PF
+
10 PF
+5V
Microcontroller
LM4040-2.5
V
D
CHB-
CHB+
D
OUTB
CSB
DIFFINA
DIFFINB
ADC122S706
www.ti.com
SNAS408A –NOVEMBER 2007–REVISED MARCH 2013
APPLICATION CIRCUITS
The following figures are examples of the ADC122S706 in typical application circuits. These circuits are basic
and will generally require modification for specific circumstances.
Data Acquisition
Figure 48 shows a basic low cost, low power data acquisition circuit. The analog and digital supply pins are
powered by the system +5V supply and the 2.5V reference voltage is generated by the LM4040-2.5 shunt
reference.
Figure 48. Low cost, low power Data Acquisition System
Current Sensing Application
Figure 49 shows an example of interfacing a pair of current transducers to the ADC122S706. The current
transducers convert an input current into a voltage that is converted by the ADC. Since the output voltage of the
current transducers are single-ended and centered around a common-mode voltage of 2.5V, the ADC122S706 is
configured with the output of the transducer driving the non-inverting inputs and the common-mode output
voltage of the transducer driving the inverting input. The output of the transducer has an output range of ±2V
around the common-mode voltage of 2.5V. As a result, a series reference voltage of 2.0V is connected to the
ADC122S706. This will allow all of the codes of the ADC122S706 to be available for the application. This
configuration of the ADC122S706 is referred to as a single-ended application of a differential ADC. All of the
elements in the application are conveniently powered by the same +5V power supply, keeping circuit complexity
and cost to a minimum.
Figure 49. Interfacing the ADC122S706 to a Current Transducer
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