ES51925
3000 Counts Smart DMM
b.) AC RMS circuit
1
2
3
4
5
6
V-
BT1
ZR3
3V
5.6V
uA
SW2
SW1
LCD Panel
C3
C4
10uF
J1
ZR1
R1
ZR2
SW SPDT
SEG01
1
2
3
4
5
6
7
8
SEG02
SEG03
SEG04
SEG05
SEG06
SEG07
SEG08
SEG09
SEG10
SEG11
SEG12
SEG13
SEG14
SEG15
BP1
0.1uF
450
D
C
B
A
D
C
B
A
uA
SW3
ZR4
C1
10uF
7.5V
C2
0.1uF
R2
45
9
10
11
12
13
14
15
16
17
18
19
mA
mA
60A
SW4
U1
R3
ZR5
ZR6
4.5
BP2
BP3
BP4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
SEG12
SEG13
SEG14
SEG15
CLAMP
VON
AON
FA
FUA
FC3
FC2
FC1
HOLD
SEL
VAHZ
RANGE
AGND
SEG12
SEG13
SEG14
SEG15
CLAMP
VON
AON
FA
FUA
FC3
SW8
C9
LBAT
220nF
220nF
LBAT
CREF+
CREF-
CINT
CAZ
BUFF
RAZ
IVSH
IVSL
OVX
OVH
OVSG
OR1
VR5
VR4
VR3
VR2
TEST5
ACVL
ACVH
ADI
ADO
OHMC4
OHMC3
C7
C8
0.1uF
CON19
R4
0.495
R8
R9
R10
R11
220K
75K
100K
100K
60A
Function Switch
SW9
1
1
IVSH
IVSL
100K
J2
J3
R6
FC2
FC1
R5
R12
100
ES51925
V -
C6
HOLD
SEL
VAHz
RANGE
NC
BKLIT
EFEN
BP1
BP2
BP3
BP4
ANNUNC
BKOUT
VR1
20K
R13
R14
R15
R16
R17
100
1K
10K
101K
1.11M
0.005
Gnd
220pF
BKLIT
RANGE
VAHZ
SEL
SW5
SW6
SW7
SW11
SW12
SW_non lock
SW10
1.5K PTC
ZR8
R7
BKLIT
EFEN
BP1
BP2
BP3
BP4
ANNUNC
SW SPST
VR1_10M
SW_non lock
SW_non lock
SW_non lock
SW_non lock
ACVL
ACVH
ZR7
ADO
R / C / D / Cont.
1
SW16
ACV / RMS
J4
HOLD
C12
22nF
C14
SW_lock
220nF
TRMS Circuit
C15
C16
470nF
47nF
-VS_ES7
+VS_ES7
VR2
500K
V -
ES7_PWR
R18
10K
APOSEL
BUZIN
SLEEP
SW13
CLAMP
1
2
3
4
8
7
6
5
C13
1uF
RL
Vin
COM
+ VS
SW_lock
SW14
ES7_PWR
ACVH
PwrDown Vout
- VS Cav
VON
AON
FA
R21
27K VR3
10K
VR
R24
9K
SW_lock
SW15
U2 ES7
C10
-VS_ES7 +VS_ES7
R19
150
R20
47K
2.2uF
+ C11
2.2uF
V -
SW_lock
SW17
C18
C19
+
C21
ZR9
5.6V
+
ADP
SW_lock
SW18
ADO
220nF
10uF
10uF
R26
C20
1uF
1
J5
FUA
FC3
VR4
50K
1K
BZ1
Buzzer
SW_lock
SW19
SW_lock
SW20
FC2
SW_lock
SW21
Title
FC1
ES51925 3000 Counts Smart DMM
SW_lock
SW22
Size
B
Number
Revision
EFEN
Application Circuit ( TRMS )
SW_lock
Date:
File:
30-Aug-2007
D:\Protel file\ES51928 Serial.ddb
Sheet of
Drawn By:
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2
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Notes:
1. The ESD protection circuits protect most of pins. However pins, V+, V-, AGND, DGND and VR1
are not protected enough because the parasitic effect must be decrease. Therefore enough external
protection is needed for assembling, carrying and keeping. In addition, components connecting to
these unprotected pins have to be soldered on board before the IC is soldered.
2. All the zener diodes above are used for IC protection. These protections are needed and these zener
diodes must be soldered on PCB first before soldering ES51925 on.
3. The OVX pin resistance have to be kept below 120kΩ for the capacitance mode accuracy (3/30nF
range). For higher voltage protection, additional configuration of PTC protection is necessary.
Ver 2.9
21
10/06/25
CYRUSTEK [ Cyrustek corporation ]
