3 1/2 AUTO DMM
Features
•
2000 count display
•
Full automatic measurement
*Voltage measurement
*Current measurement
*Resistor measurement
•
Range change function
•
Data hold function
•
Diode measurement
•
ADP mode with external reference
voltage
•
Serial data output (RS232 format)
•
Auto power off (10 mins) and re-power
on
•
Low battery detect (3V and 9V)
•
3V DC power supply
•
Back light function
ES51981
Description
ES51981 is an integrated analog-to-digital
Converter(ADC) with 2000 counts LCD
display ,automatic range selection, and 3V
DC power supply. Automatic range
selection is provided for voltage(AC/DC)
measurement, resistor measurement and
current measurement. Expensive and
bulky mechanical range switches are not
required. Other features include data
holding, diode measurement, temperature
measurement, continuity checking, low
battery detection, auto- power off,
re-power on, and RS232 data output.
Application
Digital Multimeter
1
11/01/05
3 1/2 AUTO DMM
Pin Assignment
HOLD
RANGE
SLACDC
KEY
FC5
FC4
FC3
FC2
FC1
NC
C+
C-
NC
SDO
LBAT9
V-
V-
DGND
AGND
AGND
100
90
80
ES51981
NC
V+
V+
NC
CL+
CL-
CIL
CAZL
BUFL
IVSH
IVSL
OVX
OVH
OVSG
NC
OR1
VR5
VR4
VR3
VR2
TEST5
ACVL
ACVH
NC
ADI
NC
ADO
NC
VRH
VR
1
10
70
20
60
30
40
50
NC
BKOUT
NC
XTAL
NC
OSC1
OSC2
NC
BUZOUT
BUZIN
NC
ANNUNC
BP1
BP2
BP3
BP4
SEG01
SEG02
SEG03
SEG04
SEG05
SEG06
SEG05
SEG07
SEG08
SEG09
SEG10
SEG11
SEG12
NC
NC
SEG13
SEG14
NC
SEG15
BKLIT
RS232
NC
NC
SLEEP
NC
NC
NC
NC
VBAR
NC
VR1
SGND
ADP
VA-
VA+
2
11/01/05
3 1/2 AUTO DMM
Pin Description
Pin No
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
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
ES51981
Symbol
NC
V+
V+
NC
CL+
CL-
CIL
CAZL
BUFL
IVSH
IVSL
OVX
OVH
OVSG
NC
OR1
VR5
VR4
VR3
VR2
TEST 5
ACVL
ACVH
NC
ADI
NC
ADO
NC
VRH
VR
VA+
VA-
ADP
SGND
VR1
NC
VBAR
NC
NC
NC
NC
SLEEP
NC
NC
RS232
BKLIT
SEG15
NC
Type
P
P
IO
IO
O
O
O
I
I
I
I
I
O
O
O
O
O
I/O
O
O
I
O
O
I
I
Description
Positive supply voltage, output of on-chip DC-DC converter.
Positive supply voltage, output of on-chip DC-DC converter.
High resolution positive connection for reference capacitor.
High resolution negative connection for reference capacitor.
High resolution integrator output. Connected to integral capacitor
High resolution auto-zero capacitor connection.
Integral resistor connection for high resolution buffer output
High current measurement input.
Low current measurement input
Input high voltage for resistance measurement
Output connection for resistance measurement
Sense low voltage for resistance measurement
Reference resistor connection for 200.0Ω
range
Voltage measurement ÷10000 attenuator(2000V)
Voltage measurement ÷1000 attenuator(200.0V)
Voltage measurement ÷100 attenuator(20.00V)
Voltage measurement ÷10 attenuator(2.000V)
Test pin
Negative output of AC to DC converter
Positive output of AC to DC converter.
Negative input of internal AC to DC Opamp.
Output of internal AC to DC Opamp.
Output of band-gap voltage reference .Typically –1.2V
Reference input voltage connection. Typically –100mV
For ADP. Deintegrating voltage positive input. The input should
be higher than VA-.
For ADP. Deintegrating voltage negative input. The input should
be lower than VA+.
ADP input
Signal Ground
Measurement input
Decimal point control for temperature measurement in ADP mode.
I
G
I
I
O
I
I
O
Asserts low in the sleep mode. See page 8, function description
Pulse low to enable serial data output.
Back light function. Pulse low to set BKOUT pin output
LCD segment line 15
3
11/01/05
3 1/2 AUTO DMM
…continued from previous page
49~50 SEG14~SEG1
O
3
51~52
NC
53~64 SEG12~SEG0
O
1
65
BP4
O
66
BP3
O
67
BP2
O
68
BP1
O
69
ANNUNC
O
LCD segment line 14~13
LCD segment line 12~01
LCD backplane 4
LCD backplane 3
LCD backplane 2
LCD backplane 1
Square wave output at the backplane frequency, synchronized to
BP1. ANNUNC can be used to control display annunciator. Con-
nect an LCD segment to ANNUNC to turn it on; connect an LCD
segment to its backplane to turn it off.
Enables the buzzer. Low active.
Outputs an 2KHz audio frequency signal for driving piezoelectric
buzzer when BUZIN is low.
Crystal oscillator output connection
Crystal oscillator input connection
The chip uses internal RC oscillator if pin is connected to V-, and
uses external crystal oscillator if this pin is floating or connected to
DGND
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.
Pulse low to enable HOLD mode.
Pulse low to enable manual mode and manual range selection.
Select AC/DC initial state. This pin is pull low
Pulse low to change mode. In ADP mode, if this pin is connected to
V-, the buzzer output will be off when the ADP input overflows.
Switch 5 for function selection.
Switch 4 for function selection.
Switch 3 for function selection.
Switch 2 for function selection.
Switch 1 for function selection.
Positive capacitor connection for on-chip DC-DC converter.
Negative capacitor connection for on-chip DC-DC converter.
RS232 compliant serial data output.
Low battery configuration. If 3V battery is used, connect it to AGND.
The default low-battery threshold voltage is –2.3V. If 9V battery is
used, the low battery annunciator is displayed when the voltage of
this pin is less than VRH (-1.2V)
Negative supply voltage. Connecting to battery negative terminal.
Negative supply voltage. Connecting to battery negative terminal.
Digital ground, connected to battery positive terminal.
Analog ground.
Analog ground.
ES51981
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
NC
BUZIN
BUZOUT
NC
OSC2
OSC1
NC
XTAL
NC
BKOUT
NC
HOLD
RANGE
SLACDC
KEY
FC5
FC4
FC3
FC2
FC1
NC
C+
C-
NC
SDO
LBAT9
I
O
O
I
I
O
I
I
I
I
I
I
I
I
I
O
O
O
I
96
97
98
99
100
V-
V-
DGND
AGND
AGND
P
P
G
G
G
4
11/01/05
3 1/2 AUTO DMM
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
-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℃
Rating
ES51981
Electrical Characteristics
TA=25℃, V- =
-3V
Parameter
Power supply
Operating supply current
In DCV mode
Voltage roll-over error
Voltage nonlinearity
Input Leakage
Low battery flag voltage
Zero input reading
Reference voltage and open circuit
Voltage for 200Ω measurement
Peak to peak backplane
Drive voltage
Counter time base period
Open circuit voltage for
Ω
Measurement (except 200Ω)
Symbol
Test Condition
V-
I
DD
Normal operation
I
SS
In sleep mode
REV
10MΩ input
resistor
Best case straight
NLV
line
V- to AGND
10MΩ input resistor
100KΩ resistor
between VRH and
AGND
-3.5V
≤
V
≤
-2.2V
f
OSC
= 4MHZ
Ω
and Continuity
Mode
Between V- pin and
HOLD, RANGE,
KEY, FC1, FC2,
FC3, FC4, FC5,
XTAL, BKLIT
Between V- pin
and RS232
Between GND Pin
and SLACDC
±1%
±5%
100KΩ
resister
Between
VRH
0℃<TA<70℃
Min.
-3.5
—
—
—
—
-10
-2.5
-000
-1.3
3.00
—
-0.54
Typ.
-3.0
0.9
0.1
—
—
1
-2.3
000
-1.2
3.2
1
-0.47
Max
-2.2
1.1
5
±0.1
±0.1
10
-2.1
+000
-1.1
3.40
—
-0.4
Units
V
mA
µA
%F.S
%F.S
PA
V
counts
V
V
sec
V
V
REF
Internal pull-high to 0V
Current
—
1.2
—
µA
—
µA
—
—
—
HZ
ppm/℃
—
11
1.5
Internal pull-low to V-
Current
AC frequency response at
2.000V range
Reference voltage temperature
Coefficient
TC
RF
—
—
—
40-400
400-2000
50
5
11/01/05
MicroPython Open Source section
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