ES51969
6,600 Counts Auto DMM
1.1.4 The true RMS-to-DC conversion with ES636
If ES636 is used for true RMS-to-DC measurement, the test circuit is shown in Figure 1.
Make ADO and ADI pin short, and keep TEST5 pin float. Connect OVSG pin to
AGND through a switch in ACV measurement mode.
ACV
99.5
1K
10K
101K
1.111M
OVSG
OR1
VR5
VR4
VR3
VR2
TEST5
ACVL
ACVH
-Vs +Vs
5K
4.7u
+
4.7u
-Vs
1
2
3
4
5
6
7
14
13
12
11
10 100
9
8
4
ES51969
10K
+Vs
2
3
7
TL061
N1
1
100K
6
5
N2
ES636
1.5K
-Vs
1K +Vs
500K
-Vs
1M
0.47u
-Vs
ADI
ADO
AGND
+Vs
100K
ADOHZ
10K
10K
3.3u
+
Figure 1. The true RMS-to-DC conversion with ES636
v2.6
8
08/10/06