CYRUSTEK ES51926_10

ES51926
3000 Counts Smart DMM
Features
General description
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3000 counts LCD display
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3V DC power supply
ES51926 is an integrated ADC with 3000 counts
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Conversion rate: 4 times/s (voltage mode)
LCD display driver. It could support fully
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Full automatic measurement:
automatic DMM function measurement. In
*Voltage/Current: AC/DC auto scanning
voltage or current mode, the AC or DC signals
& auto range: 3.000V~1000V
z
auto scanning. In R/D/C (passive component)
*Resistance/Diode/Capacitance(RDC scan)
mode,
(Taiwan patent no.: 326361)
capacitance or diode measurements are allowed
Auto scanning & auto range:
by fully automatic detection. A single key and
Resistance: 300.0Ω~3.000MΩ
simple switch could select all measurements.
Capacitance: 3.000nF~300.0uF
Expensive and bulky mechanical range switches
resistance
(including
continuity),
(Taiwan patent no.: 323347,453443)
are not required. A non-contact electric field
Push functions
detector (EF mode) is built-in for ac voltage
Function selection by single key
measurement also. Other features including
Range change function
range control, data hold, max/min hold, VAHz
Hold function
and back light function are available. For power
MAX/MIN function
saving, an auto power off & re-power on scheme
VAHZ function
are built-in. A sleep output is the indication of
Back light function
entering auto power off mode.
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Support non-contact voltage detection
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High voltage (> 30V) indication of LCD
display for voltage measurement
(Taiwan patent no.: 234661)
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Built-in HCF(high crest factor detection)
function in AC mode
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OL level selection (600V/1000V/1500V)
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Band-gap reference voltage output
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Auto power off (3min. or 10min.) &
re-power on
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Sleep output indication
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On-chip buzzer driver
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Low battery detection
Application
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Smart digital multi-meter
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Smart clamp meter
Ver 2.9
1
10/06/25
ES51926
3000 Counts Smart DMM
55
60
65
75
80
50
45
Cyrustek.
com.tw
85
ES51926
90
95
40
35
25
20
15
5
100
10
30
NC
NC
NC
NC
NC
ACEN
BUZOUT
APOSEL
BUZIN
SLEEP
R1K
R9KCA+
CANC
VR1
VAVA+
ADP
SGND
VR
VRH
NC
OHMC1
OHMC2
AGND
LBAT
CREF+
CREFCINT
CAZ
BUFF
RAZ
IVSH
IVSL
OVX
OVH
OVSG
OR1
VR5
VR4
VR3
VR2
TEST5
ACVL
ACVH
ADI
ADO
OHMC4
OHMC3
SEG11
SEG10
NC
NC
SEG09
SEG08
SEG07
SEG06
SEG05
SEG04
SEG03
SEG02
SEG01
OSC2
OSC1
BKSEL
CESEL
C+
CVVV+
V+
DGND
AGND
70
SEG12
SEG13
SEG14
SEG15
CLAMP
VON
AON
FA
FUA
FC3
FC2
FC1
HOLD
SEL
VAHZ
RANGE
MAX/MIN
BKLIT
EFEN
BP1
BP2
BP3
BP4
ANNUNC
BKOUT
Pin Assignment
Pin Description
Pin No
Symbol
Type
1
2
AGND
LBAT
P
I
3
4
5
6
7
8
CREF+
CREFCINT
CAZ
BUFF
RAZ
I/O
I/O
O
I
O
O
9
10
IVSH
IVSL
I
I
Ver 2.9
Description
Analog ground.
Low battery configuration. If 3V battery is used, connect it to DGND.
The default low-battery threshold voltage is –2.3V. If 9V battery is
used, the low battery enunciator is displayed when the voltage of
this pin is less than VRH (-1.2V)
Positive connection for reference capacitor.
Negative connection for reference capacitor.
Integrator output. Connect to integral capacitor
Auto-zero capacitor connection.
Buffer output pin. Connect to integral resistor
Buffer output pin in high-speed mode. Connect to high-speed integral
resistor.
High current measurement input.
Low current measurement input
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ES51926
3000 Counts Smart DMM
11
12
13
14
15
16
17
18
19
20
OVX
OVH
OVSG
OR1
VR5
VR4
VR3
VR2
TEST5
ACVL
I
I
I
O
O
O
O
O
I/O
I
21
ACVH
I
22
23
24
25
26
27
28
29
30
31
32
33
ADI
ADO
OHMC4
OHMC3
OHMC2
OHMC1
NC
VRH
VR
SGND
ADP
VA+
I
O
O
O
O
O
O
I
I
I
I
34
VA-
I
35
36
37
38
39
40
41
42
43
44
45
46 – 50
51
VR1
NC
CACA+
R9K
R1K
SLEEP
BUZIN
APOSEL
BUZOUT
ACEN
NC
BKOUT
I
I/O
I/O
O
O
O
I
I
O
O
O
52
ANNUNC
O
53
54
55
56
57
58
59
60
61
BP4
BP3
BP2
BP1
EFEN
BKLIT
MAX/MIN
RANGE
VAHz
O
O
O
O
I
I
I
I
I
Ver 2.9
Input high voltage for resistance/capacitor measurement
Output connection for resistance/capacitor measurement
Sense low voltage for resistance measurement
Reference resistor connection for 300.0Ω range
Voltage measurement ÷10000 attenuated (1000V)
Voltage measurement ÷1000 attenuated (300.0V)
Voltage measurement ÷100 attenuated (30.00V)
Voltage measurement ÷10 attenuated (3.000V)
Test pin
DC signal low input in ACV/ACA mode. Connect to negative output of
external AC to DC converter.
DC signal high input in ACV/ACA mode. Connect to positive output of
external AC to DC converter.
Negative input of internal AC to DC OP Amp.
Output of internal AC to DC OP Amp.
Filter capacitor connection for resistance mode
Filter capacitor connection for resistance mode
Filter capacitor connection for resistance mode
Filter capacitor connection for resistance mode
Output of band-gap voltage reference. Typically –1.2V
Reference input voltage connection. Typically –400mV
Signal Ground.
Measurement input in ADP mode
For ADP mode. De-integrating voltage positive input. The input should
be higher than VA-.
For ADP mode. De-integrating voltage negative input. The input should be
lower than VA+.
Measurement input.
Negative auto-zero capacitor connection for capacitor measurement
Positive auto-zero capacitor connection for capacitor measurement
Connect to a precise 9KΩ resister for capacitor measurement.
Connect to a precise 1KΩ resister for capacitor measurement.
Sleep mode indicator, asserts low in SLEEP mode. Normal V+ output.
Pull to V- to enable the BUZOUT.
Auto power off idle time selection.
Outputs a 2KHz audio frequency signal for driving piezoelectric buzzer
Output to V- when AC mode inactive and output to V+ in AC mode.
If BKLIT function is enabled, this pin will change from –3V to +3V
for 60 sec, once press BKLIT pin again within 60 sec, this pin will change
back to –3V.
Square wave output at the backplane frequency, synchronized to BP1.
ANNUNC can be used to control display annunciator. Connect a LCD
segment to ANNUNC to turn it on; connect an LCD segment to its back
plane to turn it off.
LCD backplane 4
LCD backplane 3
LCD backplane 2
LCD backplane 1
Pull-low to enable non-contact AC voltage detection
Back light function. Pulse low to set BKOUT pin output.
Pulse to V- to enable MAX/MIN function.
Pulse to V- to enable manual mode and manual range selection.
Pulse to V- to enable VAHz mode.
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10/06/25
ES51926
3000 Counts Smart DMM
62
63
64
65
66
67
68
69
70
71
72 – 77
78 – 79
80 – 88
89
90
SEL
HOLD
FC1
FC2
FC3
FUA
FA
AON
VON
CLAMP
SEG15 – 10
NC
SEG09 - 01
OSC2
OSC1
91
BKSEL
92
93
94
95
96
97
98
99
100
CESEL
C+
CVVV+
V+
DGND
AGND
I
I
I
I
I
I
I
I
I
I
O
O
I
O
Pulse to V- to select target measurement
Pulse to V- to enable HOLD function.
Switch 1 for function selection.
Switch 2 for function selection.
Switch 3 for function selection.
Switch 1 for current measurement selection.
Switch 2 for current measurement selection.
Pull to high to sense current measurement priority in auto scan mode
Pull to high to sense voltage measurement priority in auto scan mode
Switch for clamp meter application function
LCD segment line 10 – 15
LCD segment line 01 – 09
Crystal oscillator input connection
Crystal oscillator output connection
When pulled to V-, an auto back light configuration is allowed.
Configure a low level applied to BKLIT larger than 1 second, the
I
BKOUT will be active.
If BKLIT is back to high level, the BKOUT would be inactive.
I
OL selection feature control pin.
O Positive capacitor connection for on-chip DC-DC converter.
O Negative capacitor connection for on-chip DC-DC converter.
P Negative supply voltage. Connecting to battery negative terminal.
P Negative supply voltage. Connecting to battery negative terminal.
P/O Output of on-chip DC-DC converter.
P/O Output of on-chip DC-DC converter.
G Digital ground.
G Analog ground.
Absolute Maximum Ratings
Characteristic
Supply Voltage (V- to AGND)
Analog Input Voltage
V+
AGND/DGND
Digital Input
Power Dissipation. Flat Package
Operating Temperature
Storage Temperature
Ver 2.9
Rating
-4V
V- -0.6 to V+ +0.6
V+ ≥ (AGND/DGND+0.5V)
AGND/DGND ≥ (V- -0.5V)
V- -0.6 to DGND +0.6
500mW
0℃ to 70℃
-25℃ to 125℃
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10/06/25
ES51926
3000 Counts Smart DMM
Electrical Characteristics
TA=25℃, V- = -3V
Parameter
Power supply
Operating supply current
In Scan AC/DC mode
Voltage roll-over error
Voltage nonlinearity
Input Leakage
Low battery flag voltage
Zero input reading
Peak to peak backplane
drive voltage
Counter time base period
Reference voltage and open circuit
voltage for 300Ω measurement
Open circuit voltage for Ω
measurement (except 300Ω)
Internal pull-high to 0V
current
AC frequency response at 6.000V
Range
AC input response for scan mode
AC/DC voltage scan mode
[email protected]
AC/DC current scan mode
[email protected]
RDC scan mode RES sensitivity
Symbol
Test Condition
VIDD Normal operation
ISS In sleep mode
REV 10MΩ input resistor
Min.
-3.5
—
—
—
Typ.
-3.0
2.5
0.6
—
Max
-2.5
—
2.5
±0.1
Units
V
mA
µA
%F.S1
Best case straight
NLV line
—
—
±0.1
%F.S
-10
-2.4
-000
1
-2.3
000
10
-2.2
+000
PA
V
counts
3.0
3.15
3.3
V
—
1
—
sec
-1.33
-1.23
-1.13
V
-0.86
-0.78
-0.70
V
—
1.2
—
µA
V- to AGND
10MΩ input resistor
-3.5V≤ V ≤-2.2V
VREF
fOSC = 4MHZ
100KΩ resistor
between VRH and
AGND
Ω and Continuity
Mode
Between V- pin and
HOLD, RANGE,
SEL,FC1-3,FUA,
FA, VON, AON,
CLAMP, BKLIT,
MAXMIN
±1%
±5%
VR1(10MΩ input
impedance)
ADP, IVSL and IVSH
Parasitic capacitance
allowed in 3.000MΩ
range
Forward voltage
RDC scan mode DIODE sensitivity
RDC scan mode CAP sensitivity
Reference voltage temperature
100KΩ resister
coefficient
TCRF Between VRH
0℃<TA<70℃
3nF – 3.0µF
Capacitance measurement
accuracy
30µF ~ 30mF
—
—
10
40-400
—
400-2000 —
—
50000
HZ
Hz
300
450
600
mV
8
10
12
mV
—
—
200
pF
—
400
0.8
—
—
—
V
pF
—
50
—
ppm/℃
-1.5
-5
-2.0
—
—
—
1.5
5
2.0
%F.S
counts
%F.S
-5
—
5
counts
Note:
1.Full Scale
Ver 2.9
5
10/06/25
ES51926
3000 Counts Smart DMM
Functional Description
1.
Operation Modes
1.1 Voltage Measurement
A re-configurable voltage divider automatically provides a suitable range in
voltage measurement mode. The following table summarizes the full-scale ranges
in each configuration.
Configuration
VR1
VR2
VR3
VR4
VR5
Full Scale Range
300.0mV*
3.000V**
30.00V
300.0V
1000V***
Divider Ratio
1
1/10
1/100
1/1000
1/10000
Resister Connection
VR1 (10MΩ)
VR2 (1.111MΩ)
VR3 (101KΩ)
VR4 (10KΩ)
VR5 (1KΩ)
Note:
* Exists in manual mode only by RANGE key control
**This range is the default range for auto range & auto scan mode
*** Depends on CESEL selection
1.1.1 OL selection
ES51926 has a OL display selection feature archived by configuring a CESEL
pin. If pin CESEL is connected to V-, ES51926 will have a 600.0V overflow
level in DCV and ACV mode. If pin CESEL is connected to DGND, the
ES51926 will have a 1010V overflow level in DCV mode and have a 1010V
overflow level in ACV mode also. When CE is floating, a 1500V overflow level
in DCV mode but ACV is still 1010V overflow level. The meter will Show OL
when the measuring signal reaches the overflow level with beeper warning. The
configuration of CESEL is listed below.
CESEL
VDGND
Floating
Ver 2.9
DCV
600.0V
1010V
1500V
6
ACV
600.0V
1010V
1010V
10/06/25
ES51926
3000 Counts Smart DMM
1.1.2 HCF detection
ES51926 provides detection of high-crest-factor (HCF) signal in ACV auto range
mode. ES51926 senses the signal and determines it as HCF if the Vpp is large
enough. Once the signal is determined as HCF, ES51926 will jump up one
measuring range regardless of current measurement value. It takes 60ms to jump
one range up. The jumping up process will continue until the maximum range is
reached. With HCF detection, a more accurate result could be obtained. For
example, when a input signal with Vpp=200V, Vrms=40V(CF=5) was applied,
traditional DMM might stay at 30V range but shows counts with the amount of
error up to 10% or even bigger. The error rises from limited input/output swing
at internal ADC. With HCF detection, DMM will stay at 300V range and exhibits
more accurate results.
1.1.3 EF mode
ES51926 supports a non-contact ac voltage measurement, which is called electric
field measurement also. The EF mode is selected by SEL key when EF_EN is
active. The ADC input is configured from ADP pin vs. SGND. When no or less
electric field is detected, the LCD shows “EF”. If the detector senses electric
field, the strength will be showed on LCD by “-“ not digits type. Level 1(weak)
is “-“ and the level 4(strong) is “----“. Additional beeper will be output from
BUZOUT pin. The buzzer frequency depends on the strength of electric field also.
The Faster beeper means the stronger electric field (ac voltage) is sensed.
Ver 2.9
7
10/06/25
ES51926
3000 Counts Smart DMM
1.2 Current Measurement
1.2.1 For multi-meter application
ES51926 has 2 automatic and 1 manual current measurement modes for
multi-meter. The following table summarizes the full-scale range of each mode.
When ES51926 operates in the current measurement modes for multi-meter, it
takes high input from pin IVSH or IVSL, low input from pin SGND and
reference voltage from pin VR.
Mode
Automatic1
Automatic2
Manual
Full Scale
300.0µA / 3000µA
30.00mA / 300.0mA
30.00A
Input Terminal
IVSL/IVSH V.S. SGND
IVSL/IVSH V.S. SGND
IVSH V.S. SGND
Full scale
150.0mV
150.0mV
150.0mV
1.2.2 For clamp meter application
ES51926 has 2 automatic and 4 manual current measurement modes for Clamp
meter. The following table summarizes the full-scale range of each mode. When
ES51926 operate in the automatic mode1&2, it takes high input from
IVSH/IVSL (higher range/lower range), low input from SGND and reference
voltage from VR. When ES51926 operate in the manual mode1~4, it takes high
input from ADP, low input from SGND and reference voltage from VA+ & VA-.
Mode
Automatic1
Automatic2
Manual1
Manual2
Manual3
Manual4
Ver 2.9
Full Scale
300.0A / 3000A
30.00A / 300.0A
3.000A
30.00A
300.0A
3000A
Input Terminal
IVSL/IVSH V.S. SGND
IVSL/IVSH V.S. SGND
ADP V.S. SGND
ADP V.S. SGND
ADP V.S. SGND
ADP V.S. SGND
8
Full scale
300.0mV
300.0mV
300.0mV
300.0mV
300.0mV
300.0mV
10/06/25
ES51926
3000 Counts Smart DMM
1.3 Resistance Measurement
A re-configurable divider automatically provides a suitable full-scale range in
resistance measurement mode. The following table summarizes the full-scale
ranges and the reference resistors in each configuration.
Configuration
OR1
OR2
OR3
OR4
OR5
OR6
Full Scale Range
300.0Ω*
3.000KΩ
30.00KΩ
300.0KΩ
3.000MΩ
30.00MΩ**
Relative Resistor
OR1
VR5
VR4
VR3∥VR1
VR2∥VR1
VR1
Equivalent value
100Ω
1KΩ
10KΩ
100KΩ
1MΩ
10MΩ
Note: * When auto scan mode is set, continuity check is implemented in this range
** When auto scan mode is set, the 30.00MΩ range is omitted
1.3.1 Continuity check
Continuity check shares the same configuration with 300.0Ω manual resistance
measurement mode and has buzzer output to indicate continuity. The buzzer
generates 2KHz beep whenever the reading is less than 30Ω.
1.4 Diode Measurement
Diode measurement mode shares the same configuration with 3.000V manual
voltage measurement mode and has buzzer output to indicate continuity. The
buzzer generates a 2KHz sound whenever the reading is less than 30mV. If the
test circuit is open or the voltage drop between the two ports of the device (diode)
under test is larger than 2V, the LCD panel will show “OL”.
Ver 2.9
9
10/06/25
ES51926
3000 Counts Smart DMM
1.5 Capacitance Measurement
The following table summarizes the eight ranges of capacitance measurement
mode:
Configuration
C1
C2
C3
C4
C5
C6
C7
C8
Full Scale Range
3.000nF
30.00nF
300.0nF
3.000uF
30.00uF
300.0uF
3.000mF*
30.00mF**
Relative Resistor
20kΩVR+100kΩ
20kΩVR+100kΩ
101kΩ
10kΩ
R9K / R1K
R9K / R1K
R9K / R1K
R9K / R1K
Note: * & ** The C7-C8 both range is not available for auto scan mode
In order to obtain an accurate reading, a capacitor must be discharged before
measurement begins. The chip has a built-in discharge mode to automatically
discharge the capacitor. In discharge mode, the LCD displays “dIS.C”
Discharging through the chip is quite slow. We recommend users to discharge the
capacitor with some other apparatus.
1.6 Auto power off mode (APO)
1.6.1 Idle Time selection
ES51926 has a default auto power off function. If the meter is idle for more than
the given Idle Time, the chip automatically turns the power off. The idle time to
trigger the auto power off function is determined by pin ‘APOSEL’. If pin
APOSEL is connected to V-, the Idle Time will be set to 3 minutes. If pin
APOSEL is connected to DGND or floating, the Idle Time will be set to 10
minutes. When APO happens, the state of the meter is saved. If the APO is
necessary to be cancelled, power on the ES51926 when any of the push key,
except for HOLD, is pressed down simultaneously.
Ver 2.9
10
10/06/25
ES51926
3000 Counts Smart DMM
1.6.2 Sleep output
The meter enters sleep mode after auto power-off or push SEL key to last for 2s.
The SLEEP pin asserts low (-3V) in the sleep mode, and asserts high (+3V, not 0V)
after re-power on.
1.6.3 Re-power on
After auto power-off is active, pushing any of the push function or changing the
measurement function can turn on the meter again. If the meter is re-powered on
by changing measurement function, the saved state is cleared. If the meter is
re-powered on by push functions, the chip restores the saved state and enters
HOLD mode. The LCD displays the saved value except for the auto scan mode.
Ver 2.9
11
10/06/25
ES51926
3000 Counts Smart DMM
2.
Functional Modes Table
Measurement mode depends on the logic level of FC1, FC2, FC3, FUA, FA,
VON, AON and CLAMP.
FC1
1
1
1
1
1
1
1
0
0
0
1
1
FC2 FC3 FUA FA VON AON CLAMP
X
0
X
X
X
0
0
X
0
1
0
X
1
0
X
0
0
0
X
1
0
X
0
0
1
X
1
0
X
0
X
X
1
X
1
X
0
1
0
0
X
1
X
0
0
0
0
X
1
1
0
X
X
X
X
X
0
1
X
X
0
X
1
1
1
X
X
0
X
1
0
1
X
X
0
X
1
1
1
X
X
0
X
1
Functional Mode(pushing SEL key)
VAUTOÆVACÆVDCÆEF*ÆVAUTOÆ…
IAUTOÆIACÆIDCÆIAUTOÆ…(uA)
IAUTOÆIACÆIDCÆIAUTOÆ…(mA)
IAUTOÆIACÆIDCÆIAUTOÆ…(A)
VAUTOÆVACÆVDCÆVAUTOÆ…
IAC(300.0A/3000A)
IAC(30.00A/300.0A)
RDCAUTOÆRÆDÆCÆRDCAUTOÆ…
IAUTOÆIACÆIDCÆIAUTOÆ…(3.000A)
IAUTOÆIACÆIDCÆIAUTOÆ…(30.00A)
IAUTOÆIACÆIDCÆIAUTOÆ…(300.0A)
IAUTOÆIACÆIDCÆIAUTOÆ…(3000A)
Input
VR1,ADP
IVSH/IVSL
IVSH/IVSL
IVSH
VR1
IVSH/IVSL
IVSH/IVSL
VR1
ADP
ADP
ADP
ADP
Note: * EF mode could be selected when EF_EN is active.
3.
Push Function
All the enabled push functions will be reset when the measurement mode is
changed by external switch. Change measurement mode by SEL function will
reset enabled RANGE, HOLD, MAX/MIN, and VAHz functions. The following
table lists the available function versus every measurement mode.
SEL
RANGE
HOLD MAX/MIN
VSCAN
O
X
X
X
VAC
O
O
O
O
VDC
O
O
O
O
EF
O
X
X
X
ISCAN
O
X
X
X
IAC
O
O*
O
O
IDC
O
O*
O
O
RDCSCAN
O
X
X
X
Resistance
O
O
O
O
Continuity
O
X
O
O
Diode
O
X
O
O
Capacitance
O
O
O
O
Note: For ADP input, RANGE is not available
Ver 2.9
12
VAHz
O
O
O
X
O
O
O
X
X
X
X
X
BKLIT
O
O
O
O
O
O
O
O
O
O
O
O
10/06/25
ES51926
3000 Counts Smart DMM
3.1 Select function
When power on or SEL key is pressed longer than one second, ES51926 will be
power-on reset to auto scan mode, which scanning mode is determined by
[FC1-FC3] function set. In auto scan mode, the ES51926 automatically selects
the appropriate measurement mode and range. Pushing the SEL key less than one
second could select the target measurement function. Pushing the key larger than
two seconds, the ES51926 will enter power down mode. If power down mode is
entered, only press SEL key to last for one second or apply the power to Vterminal could re-power on the ES51926. The following figure shows the state
transition.
Push SEL key < 1s
V/A
ac/dc auto scan
Push SEL key > 1s
Power on reset
AC mode
measurement
DC mode
measurement
EF* mode
measurement
Push SEL key > 2s Æ enter power down mode
R/D/C
auto scan
Continuity
measurement
Resistance
measurement
Diode
measurement
Capacitance
measurement
Push SEL key < 1s
Note: * Available when EF_EN is active only
Ver 2.9
13
10/06/25
ES51926
3000 Counts Smart DMM
3.2 Range function
RANGE pin switches to and from automatic and manual mode, and while in
manual mode, changes the full-scale range. The following figure shows the state
transition.
1 push < 1 sec
Automatic
Mode
Manual
Mode
1 push > 1 sec
Range up
1 push < 1 sec
3.3 Hold and delay-hold function
The data hold mode makes the meter stop updating the LCD panel. This mode
can be nested in most of the special modes. In auto scanning mode, the HOLD
key is not available. Enabling hold function in automatic mode makes the meter
switch to manual mode. Hold function can be cancelled by changing the
measurement mode, pressing RANGE, or push HOLD again.
The delay-hold function is enabled when HOLD key is pressed larger than 2
seconds. When delay-hold function is entered successfully, the meter will stop to
update the LCD data after six seconds delayed. During the six seconds waiting,
the HOLD symbol on LCD panel will be blinking.
Normal mode Push < 2s HOLD mode
(Auto/Manual) Push < 2s
(Manual)
Push > 2s
Push < 2s
Ver 2.9
Push > 2s
6sec past
Delay State
(Auto/Manual)
14
10/06/25
ES51926
3000 Counts Smart DMM
3.4 Max/Min + Hold function
The meter displays the maximum or minimum value of the input in Max/Min
mode. When MAX/MIN is pressed for the first time, the meter displays the
maximum value. The meter displays the minimum value, when it is pressed again.
When MAX/MIN is pressed for the third time, the meter displays current value.
The meter returns to normal operation if MAX/MIN is pressed and held for longer
than one second. Pressing HOLD key in Max/Min mode makes the meter stop
updating the maximum or the minimum value.
1 push<1s
Original state
(Automatic/manual)
1 push>1s
1 push>1 sec
1 push>1 sec
“MAX” active 1push<1s “MIN” active 1push<1s “Max” “MIN” blink
min value
current value
max value
Push HOLD
1push<1s
Push HOLD
Push HOLD
“MAX”“MIN” “H” blink
“MIN” “H” active
“MAX” “H” active
hold max value. 1push<1s hold min value. 1push<1s hold current value.
1push<1s
3.5 VAHz function
When voltage or current measurement mode is selected, the VAHz funtion is
available. Push VAHz key to select this frequency measurement mode. The
frequency is measured by auto ranging. The maximum frequency range is
100kHz. The sensitivity of signal input is 10% full scale of voltage or current
mode typically.
Configuration
FR1
FR2
FR3
Ver 2.9
Range
3.000KHz
30.00KHz
100.0KHz
15
10/06/25
ES51926
3000 Counts Smart DMM
3.6 Back light function
When BKSEL is set to DGND or floating, push the BKLIT key to enable the back
light output driving ON/OFF. If the auto back light configuration is active, the
BKLIT becomes a control input for external light sensed circuit. Set to low for one
second to active the back light output driving. Set to high then the driving output is
inactive immediately.
BKSEL
DGND or floating
V-
4.
Configuration
Normal back light function
Auto back light function
Miscellaneous
The conditions, which the meter turns on the buzzer, include:
(1) Changing measurement mode generates one beep.
(2) Pressing any of the push functions generates one beep, if the function is valid.
(3) Power on and re-power on generate one beep.
(4) Input overflow in voltage and current mode generates one beep every 0.3
seconds (or 3.33 beeps per second.)
(5) Continuity (diode) check generates a continuous 2KHz beep whenever the
measurement is less then 30Ω(30mV)
(6) Auto power off or power down by SEL key generates a 2KHz beeper that lasts
for 1.5 seconds.
The following figures show the output waveform from the BUZOUT pin.
0.5 mS
(a) Continuous 2KHz beep
0.15 sec
0.3 sec
(b) 3.33 beep/sec
Ver 2.9
16
10/06/25
ES51926
3000 Counts Smart DMM
4.1 LCD configuration
S1
BP1
S2
S3
S14 S12
S7 S8 S9 S10 S11
S15
S4 S5 S6
SCAN AUTO MANU
HOLD
S13
MAX MIN
APO
BP2
µ2 m2 V A
AC
n µ1 m1 F
BP3
DC
M K Ω Hz
BP4 BATT
SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08 SEG09
BP1 SCAN AUTO
BP2
AC
BP3
DC
BP4 BATT DP3
A4
F4
E4
D4
MANU
B4
G4
C4
A3
F3
E3
D3
HOLD
B3
G3
C3
F2
E2
DP2
APO
A2
G2
D2
B2
C2
DP1
SEG10 SEG11 SEG12 SEG13 SEG14 SEG15
BP1
A1
BP2
F1
BP3
BP4
Ver 2.9
µ2
M
n
MAX
B1
m2
K
µ1
MIN
E1
G1
V
Ω
m1
D1
C1
A
F
17
Hz
10/06/25
ES51926
3000 Counts Smart DMM
LCD Backplane Waveform
V- +3.2
VV- +3.2
VV- +3.2
VV- +3.2
VV- +3.2
V-
4.2 LCD display on condition
LCD annunciates
V
A
Ω
F
Hz
DC
AC
SCAN
AUTO
MANU
HOLD
Max / Min
m1
µ1
n
m2
µ2
M
K
APO
Ver 2.9
Condition
In voltage measurement mode, and diode measurement mode.
In current measurement mode.
In resistance measurement mode, and continuity mode.
In capacitance measurement mode.
In continuity check mode.
In diode mode.
In VAHZ frequency mode.
In DC voltage or DC current mode.
In AC voltage or AC current mode.
When auto scan mode is selected
When automatic full scale range selection is enabled.
In manual mode.
When the reading is exceeding 30V in DCV or ACV, the DNAGER symbol will be
displayed on
When HOLD function is enabled. When delay-hold is selected, the HOLD symbol
will be blinking for 6 seconds.
When Max or Min function is enabled.
In capacitor measurement mode and the full scale range is in the order of mF.
In capacitor measurement mode and the full scale range is in the order of uF.
In capacitor measurement mode and the full scale range is in the order of nF.
In voltage or current measurement mode and the full scale range is in the order of 10-3.
In current measurement mode and the full scale range id in the order of uA.
In resistance measurement mode and the full scale range is in the order of MΩ
In resistance measurement mode and the full scale range is in the order of KΩ
When auto power off function is enabled.
18
10/06/25
ES51926
3000 Counts Smart DMM
Test Circuit
1. Voltage test
4. Current test
AGND
OVSG
100
1K
10K
101K
1.111M
D1
OR1
VR5
VR4
VR3
VR2
ADO
D2
+1.0u
ADI
ACVL
ACVH
TEST5
15K
15K
10K
+4.7u
10K
0.005
AGND
SGND
30A
0.495
mA
4.5
A
V
R
100K
uA
uA
mA
uA
V
R
1
mA
50
100K
5. Diode test
10M
AGND
-400mV
Z1
6V
Z2
2. Resistance test
22n
220n
OHMC3
470n
PTC
1.5K
47n
100
Z1
6V
Z2
100
1K
10K
101K
1.111M
OVH
100
Voltage input
OVX
OHMC4
IVSH
IVSL
450
PTC
1.5K
VR1
10M
1.111M
VR2
OHMC2
OVSG
OHMC1
OVH
OVSG
6. Low battery
OR1
VR5
VR4
VR3
VR2
9V
680K
BA
SGND
AGND
LBAT9
TT
270K
0.1u AGND
V-
0V
3. Current test for clampmeter
7. EF test
EFin+
RL
VR
R
100K
100k
60M
ADP
SGND
EFin-
AGND
SGND
AGND
VA+
400mV
Ver 2.9
ADP
19
VA-
10/06/25
ES51926
3000 Counts Smart DMM
Application Circuit
a.) AC average rectified circuit
1
2
3
4
6
5
V-
C7
C8
0.495
R7
R8
IVSH
R9
R10
IVSL
100K
60A
SW6
1
J2
R6
R5
220pF
20K
1
SW7
J4
R17
SW SPST
VR1_10M
R / C / D / Cont.
C6
VR1
0.005
Gnd
0.47uF
4MHz
SEG10
SEG11
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
mA
SW5
1.5K PTC
ZR7
ZR8
1
C9
220nF
LBAT
0.1uF
220nF
220K
75K
100K
100K
R11
100
R12
R13
R14
R15
R18
100
1K
10K
101K
1.11M
TEST5
ACVL
ACVH
ADI
ADO
J3
B
C11
C13
22nF
220nF
AGND
DGND
V+
V+
VVCC+
CESEL
BKSEL
OSC1
OSC2
SEG01
SEG02
SEG03
SEG04
SEG05
SEG06
SEG07
SEG08
SEG09
NC
NC
SEG10
SEG11
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
AGND
LBAT
CREF+
CREFCINT
CAZ
BUFF
RAZ
IVSH
IVSL
OVX
OVH
OVSG
OR1
VR5
VR4
VR3
VR2
TEST5
ACVL
ACVH
ADI
ADO
OHMC4
OHMC3
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
MAX/MIN
BKLIT
EFEN
BP1
BP2
BP3
BP4
ANNUNC
BKOUT
ES51926
SEG12
SEG13
SEG14
SEG15
CLAMP
VON
AON
FA
FUA
FC3
FC2
FC1
HOLD
SEL
VAHZ
RANGE
MZX/MIN
BKLIT
EFEN
BP1
BP2
BP3
BP4
ANNUNC
D
J1
SEG01
SEG02
SEG03
SEG04
SEG05
SEG06
SEG07
SEG08
SEG09
SEG10
SEG11
SEG12
SEG13
SEG14
SEG15
BP1
BP2
BP3
BP4
U1
R4
60A
7.5V
ZR6
4.5
C
ZR4
C2
0.1uF
mA
SW4
R3
ZR5
0.1uF
LCD Panel
SEG01
SEG02
SEG03
SEG04
SEG05
SEG06
SEG07
SEG08
SEG09
45
C4
C1
10uF
+
R2
10uF
+
uA
SW3
5.6V
C3
C5
450
ZR3
Y1
ZR2
CESEL
BKSEL
R1
OHMC2
OHMC1
NC
VRH
VR
SGND
ADP
VA+
VAVR1
NC
CACA+
R9K
R1K
SLEEP
BUZIN
APOSEL
BUZOUT
ACEN
NC
NC
NC
NC
NC
ZR1
+
SW2
SW1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
C
CON19
Function Switch
VBKLIT
VCLAMP
SW8
SW_non lock
VON
MZX/MIN SW9
SW_non lock
RANGE
AON
SW10
SW_non lock
VAHZ
SW11
FA
SW_non lock
C10
ADI
R21
15K
R22
15K
47nF
C12
R23
1uF
27K VR3
VR
10K
1uF
+
D1
1N4148
D2
ACVH
IN4148
ADO
1
J5
ACVL
A
FC3
FC2
SLEEP
FC1
R26
9K
EFEN
220nF
ZR9
R25
1K
4
SW_lock
SW16
SW_lock
SW17
B
SW_lock
SW18
SW_lock
SW19
SW_lock
SW20
SW_lock
SW21
SW_lock
SW22
SW_lock
BZ1
Buzzer
A
ES51926 3000 Counts Smart DMM
Number
Revision
Application Circuit ( Average )
30-Aug-2007
D:\Protel file\ES51928 Serial.ddb
5
Sheet of
Drawn By:
6
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 ES51926 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.
20
SW_lock
SW15
5.6V
B
Ver 2.9
SW14
V-
Date:
File:
3
SW13
SW_non lock
Size
2
HOLD
FUA
SW_non lock
Title
1
SW12
BUZIN
C18
ADP
SEL
APOSEL
R24
C17
C15
TEST5
4.7uF
C16
10K
100K
R16
470nF
VR1_10M R20
10K
C14
+
VR2
+
Average Circuit
26
27
28
56K 29
30
31
32
VA+
33
34
VA10M 35
36
470nF
37
38
39
40
41
42
43
44
45
46
47
48
49
50
SW SPDT
R19
D
3V
+
BT1
uA
10/06/25
ES51926
3000 Counts Smart DMM
b.) AC RMS circuit
4
SW4
mA
45
R3
R4
C8
0.495
60A
SW10
MZX/MIN SW6
SW SPST
VR1_10M
SW_non lock
SW7
SW_non lock
ZR7
220K
75K
100K
100K
1.5K PTC
R12
100
R13
R14
R15
R16
R17
100
1K
10K
101K
1.11M
ACVL
ACVH
ZR8
ADO
R / C / D / Cont.
SW11
1
SW_non lock
ACV / RMS
J4
SW17
SW_lock
SW_non lock
C10
C12
22nF
220nF
AGND
DGND
V+
V+
VVCC+
CESEL
BKSEL
OSC1
OSC2
SEG01
SEG02
SEG03
SEG04
SEG05
SEG06
SEG07
SEG08
SEG09
NC
NC
SEG10
SEG11
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
AGND
LBAT
CREF+
CREFCINT
CAZ
BUFF
RAZ
IVSH
IVSL
OVX
OVH
OVSG
OR1
VR5
VR4
VR3
VR2
TEST5
ACVL
ACVH
ADI
ADO
OHMC4
OHMC3
TRMS Circuit
SW_non lock
-VS_ES7
B
VR2
+VS_ES7
500K
C13
470nF
C14
47nF
FUA
FC3
A
FC2
FC1
EFEN
-VS_ES7
SW_lock
SW18
SW_lock
SW19
C17
+
10uF
10uF
R19
R20
150
47K
ACVH
R21
ES7
C19
2.2uF
1uF
27K VR3
VR
10K
+ C20
2.2uF
VR4
50K
C18
1uF
C15
C11
8
7
6
5
100K
COM
+ VS
Vout
Cav
U2
+VS_ES7
C16
RL
Vin
PwrDown
- VS
+
1
2
3
4
ES7_PWR
+
FA
SW_lock
SW15
SW_lock
SW16
C
B
APOSEL
BUZIN
SLEEP
R24
9K
V-
R25
AON
10K
SW14
+
VON
SEG12
SEG13
SEG14
SEG15
CLAMP
VON
AON
FA
FUA
FC3
FC2
FC1
HOLD
SEL
VAHZ
RANGE
MZX/MIN
BKLIT
EFEN
BP1
BP2
BP3
BP4
ANNUNC
ES7_PWR
R18
VR1_10M R23
VCLAMP
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
MAX/MIN
BKLIT
EFEN
BP1
BP2
BP3
BP4
ANNUNC
BKOUT
ES51926
R22
SW13
R7
LBAT
0.1uF
220nF
220pF
20K
1
J3
C9
220nF
C6
VR1
0.005
Gnd
SW_non lock
SW12
R6
R5
SW5
R8
R9
IVSH
R10
R11
IVSL
100K
60A
SW9
1
J2
HOLD
7.5V
OHMC2
OHMC1
NC
VRH
VR
SGND
ADP
VA+
VAVR1
NC
CACA+
R9K
R1K
SLEEP
BUZIN
APOSEL
BUZOUT
ACEN
NC
NC
NC
NC
NC
C7
V-
SEL
D
26
27
28
56K 29
30
31
32
VA+
33
VA34
10M 35
36
470nF
37
38
39
40
41
42
43
44
45
46
47
48
49
50
mA
SW8
C
VAHZ
C2
0.1uF
ZR6
4.5
CON19
RANGE
0.1uF
ZR4
C1
10uF
U1
ZR5
Function Switch
BKLIT
C4
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
R2
4MHz
uA
10uF
0.47uF
SW3
5.6V
C3
C5
450
ZR3
Y1
ZR2
+
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
R1
V-
+
ZR1
SW SPDT
+
SEG01
SEG02
SEG03
SEG04
SEG05
SEG06
SEG07
SEG08
SEG09
SEG10
SEG11
SEG12
SEG13
SEG14
SEG15
BP1
BP2
BP3
BP4
D
uA
SW2
SW1
J1
3V
+
LCD Panel
6
5
BT1
SEG10
SEG11
3
SEG01
SEG02
SEG03
SEG04
SEG05
SEG06
SEG07
SEG08
SEG09
2
CESEL
BKSEL
1
C21
ADP
ADO
1
ZR9
220nF
R26
1K
BZ1
Buzzer
J5
SW_lock
SW20
5.6V
SW_lock
SW21
A
SW_lock
SW22
Title
SW_lock
SW23
Size
B
SW_lock
Date:
File:
1
2
3
4
ES51926 3000 Counts Smart DMM
Number
5
21
Sheet of
Drawn By:
6
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 ES51926 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
Revision
Application Circuit ( TRMS )
30-Aug-2007
D:\Protel file\ES51928 Serial.ddb
10/06/25
ES51926
3000 Counts Smart DMM
Package Information
7.1
100 Pin LQFP Package
7.2
Dimension Parameters
Ver 2.9
22
10/06/25