Datasheet

A1
V
+
1
LM35
V
+
pH ELECTRODE
pH ELECTRODE TEMPERATURE
R
3
10 k:
R
4
10 k:
+
-
A2
V
+
R
1
10 k:
R
2
10 k:
V
-
V
-
+
-
ADC12034
0.01 PF
0.1 PF
10 PF
V
D
+
CH0
CH1
V
REF
-
V
REF
+
DGND
0.01 PF
10 PF
AGND
V
OUT
V
A
+
V
+
V
+
LM4140A
6
2
1,4,7,8
3
R
5
10 k:
R
6
3.3 k:
V
OFFSET
= 0.5012V
0.1 PF
R
T
-V
+
1 PF
75:
LMP7701, LMP7702, LMP7704
www.ti.com SNOSAI9H –SEPTEMBER 2005–REVISED MARCH 2013
Figure 56. pH Measurement Circuit
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Product Folder Links: LMP7701 LMP7702 LMP7704