Cyrustek ES51981 3 1/2 auto dmm Datasheet

ES51981
3 1/2 AUTO DMM
Features
Description
• 2000 count display
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.
• Full automatic measurement
*Voltage measurement
*Current measurement
*Resistor measurement
• Range change function
• Data hold function
• Diode measurement
• ADP mode with external reference
voltage
Application
Digital Multimeter
• 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
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ES51981
3 1/2 AUTO DMM
Pin Assignment
HOLD
RANGE
SLACDC
KEY
FC5
FC4
FC3
FC2
FC1
NC
C+
CNC
SDO
LBAT9
VVDGND
AGND
AGND
100
NC
V+
V+
NC
CL+
CLCIL
CAZL
BUFL
IVSH
IVSL
OVX
OVH
OVSG
NC
OR1
VR5
VR4
VR3
VR2
TEST5
ACVL
ACVH
NC
ADI
NC
ADO
NC
VRH
VR
90
80
1
10
70
20
30
60
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
VAVA+
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ES51981
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
Symbol
NC
V+
V+
NC
CL+
CLCIL
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+
32
VA-
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
ADP
SGND
VR1
NC
VBAR
NC
NC
NC
NC
SLEEP
NC
NC
RS232
BKLIT
SEG15
NC
Type
Description
P
P
Positive supply voltage, output of on-chip DC-DC converter.
Positive supply voltage, output of on-chip DC-DC converter.
IO
IO
O
O
O
I
I
I
I
I
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
O
O
O
O
O
I/O
O
O
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.
I
Negative input of internal AC to DC Opamp.
O
Output of internal AC to DC Opamp.
O
I
I
I
G
I
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
I
Decimal point control for temperature measurement in ADP mode.
O
Asserts low in the sleep mode. See page 8, function description
I
I
O
Pulse low to enable serial data output.
Back light function. Pulse low to set BKOUT pin output
LCD segment line 15
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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
70
71
72
NC
BUZIN
BUZOUT
73
74
75
76
77
NC
OSC2
OSC1
NC
XTAL
78
79
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. Connect an LCD segment to ANNUNC to turn it on; connect an LCD
segment to its backplane to turn it off.
I
O
Enables the buzzer. Low active.
Outputs an 2KHz audio frequency signal for driving piezoelectric
buzzer when BUZIN is low.
O
I
Crystal oscillator output connection
Crystal oscillator input connection
I
NC
BKOUT
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
O
80
81
82
83
84
NC
HOLD
RANGE
SLACDC
KEY
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.
I
I
I
I
85
86
87
88
89
90
91
92
93
94
95
FC5
FC4
FC3
FC2
FC1
NC
C+
CNC
SDO
LBAT9
I
I
I
I
I
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.
O
O
Positive capacitor connection for on-chip DC-DC converter.
Negative capacitor connection for on-chip DC-DC converter.
O
I
96
97
98
99
100
VVDGND
AGND
AGND
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.
P
P
G
G
G
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ES51981
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
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℃
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
Symbol
Test Condition
VIDD
Normal operation
ISS
In sleep mode
REV 10MΩ input
resistor
Best case straight
NLV
line
VREF
Peak to peak backplane
Drive voltage
Counter time base period
Open circuit voltage for Ω
Measurement (except 200Ω)
Internal pull-high to 0V
Current
Internal pull-low to VCurrent
AC frequency response at
2.000V range
Reference voltage temperature
Coefficient
TCRF
V- to AGND
10MΩ input resistor
100KΩ resistor
between VRH and
AGND
-3.5V≤ V ≤-2.2V
fOSC = 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℃
5
Min.
-3.5
—
—
—
Typ.
-3.0
0.9
0.1
—
Max
-2.2
1.1
5
±0.1
Units
V
mA
µA
%F.S
—
—
±0.1
%F.S
-10
-2.5
-000
1
-2.3
000
10
-2.1
+000
PA
V
counts
-1.3
-1.2
-1.1
V
3.00
3.2
3.40
V
—
1
—
sec
-0.54
-0.47
-0.4
V
—
1.2
—
—
11
—
1.5
µA
µA
—
—
40-400
400-2000
—
—
HZ
—
50
—
ppm/℃
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ES51981
3 1/2 AUTO DMM
Note:
1.Full Scale
Function Description
1. Operating Modes
1.1 Voltage Measurement
A reconfigurable 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
VR3
VR5
Full Scale Range
200.0mV
2.000V
20.00V
200.0V
2000V
Divider Ratio
1
1/10
1/100
1/1000
1/10000
Resister Connection
R2 / (R1+R2)
R3 / (R1+R3)
R4 / (R1+R4)
R5 / (R1+R5)
1.
200.0mV range only exists in manual mode.
2.
In the 2000V range, if the digit numbers is larger than 1000V, LCD will display
“OL”.
The measurement of true RMS using ES636
If ES636 (or other true RMS-to-DC converter chip) is used for true RMS measurement,
the suggested application circuit is shown below. When ES636 is used for true RMS,
ADO and ADI pin short together, TEST5 pin keeps floating, and ACVL pin connects to
SGND. And the OVSG pin shorts to AGND through a switch.
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ES51981
3 1/2 AUTO DMM
2.2u
+
-Vs
14
13
12
11
10 150
9
8
ES636
4.7u
1
2
3
4
5
6
7
100
1K
10K
101K
1.111M
+Vs
OVSG
OR1
VR5
VR4
VR3
VR2
ES51981
ACV
TEST5
ACVL
ACVH
10K +Vs
500K
2.2u
+
-Vs
ADI
ADO
AGND
1k
22k
1.2 Resistance Measurement
A reconfigurable 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
200.0Ω
2.000KΩ
20.00KΩ
200.0KΩ
2.000MΩ
20.00MΩ
Divider Ratio
R6
R5
R4
R1‖R3
R1‖R2
R1
Resister Connection
100Ω
1KΩ
10KΩ
100KΩ
1MΩ
10MΩ
1.3 Current measurement
Current measurement has three modes. The following table summarizes the full scale
range of each mode.
Mode
Automatic Mode 1
Automatic Mode 2
Automatic Mode 3
Manual Mode
Range Selection
µA
mA
A
A
7
Full Scale
200.0µA / 2000µA
20.00mA / 200.0mA
20.00A/2.000A
20.00A
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ES51981
3 1/2 AUTO DMM
1.4 Continuity Check
Continuity check shares the same configuration with 200.0Ω manual resistance
measurement mode, but with buzzer output to indicate continuity. The buzzer generates a
2KHz sound whenever the digit number less than 25Ω. Because the cycle time of
measurement is only 50ms, the least significant digit will not display.
1.5 Diode Measurement
Diode measurement mode shares the same configuration with 2.000V manual voltage
measurement mode. 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”. The
buzzer generates a 2KHz sound whenever the digit number is less than 0.25V. Because
the cycle time of measurement is only 50ms, the least significant digit will not display.
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1.6 Auto power off
ES51981 has a default auto power off function. If the meter idles for more than 10
minutes, the chip automatically turns the power off. When this happens, the state of the
meter is saved. In order to disable auto power off function, power on the meter when
any of the push function, except for HOLD, is pressed down. In addition, when RS232
output is active, the auto power-off function is also disabled. The APO sign on the LCD
panel indicates whether the auto power-off is enabled or not.
Note: Powering on the meter while pressing HOLD turns on all LCD segment until
HOLD is pressed again.
1.7 Sleep
The meter enters sleep mode after auto power off. The SLEEP pin asserts low (-3V) in
the sleep mode, and asserts high (+3V, not 0V) after re-power on.
1.8 Re-power on
After auto power-off, pushing any of the push function or changing the rotary mode can
turn on the meter again. If the meter is re-powered on by changing the rotary mode, 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.
2. Measurement Mode Switching
Measurement mode depends on the logic level of FC1, FC2, FC3, FC4, FC5, and KEY.
When FC5 is HIGH, the measurement modes are listed in the following table.
SLACDC
0
0
0
0
0
1
1
1
1
1
X
X
X
X
X
FC1
1
1
1
1
0
1
1
1
1
0
0
0
0
0
0
FC2
0
1
1
0
0
0
1
1
0
0
0
1
0
1
1
FC3
1
0
1
0
0
1
0
1
0
0
1
0
0
1
0
FC4
1
1
1
1
0
1
1
1
1
0
1
1
1
1
0
Mode
Function of KEY
Voltage Measurement
DCV(initial) ↔ACV
Current Measurement(µA)
DCA(initial) ↔ACA
Current Measurement(mA)
DCA(initial) ↔ ACA
Manual Current Measurement(A) DCA (initial) ↔ACA
Auto Current Measurement(A)
DCA(initial)
Voltage Measurement
ACV (initial) ↔DCV
Current Measurement(µA)
ACA(initial) ↔DCA
Current Measurement(mA)
ACA (initial) ↔DCA
Manual Current Measurement(A) ACA (initial) ↔DCA
Auto Current Measurement(A)
ACA (initial)
Resistance Measurement
Ω ↔ Continuity
Resistance Measurement
Ω ↔ Diode
Continuity Check
Continuity Diode
Resistance Measurement
Ω ↔ Continuity ↔Diode
—
Temperature(℃)
Ps. X means “don’t care”
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3 1/2 AUTO DMM
When FC5 is LOW, KEY is disable. The corresponding measurement modes are list
below
SLACDC
0
0
0
0
0
1
1
1
1
1
X
X
X
X
X
FC1
1
1
1
1
0
1
1
1
1
0
0
0
0
0
0
FC2
0
1
1
0
0
0
1
1
0
0
0
1
0
1
1
FC3
1
0
1
0
0
1
0
1
0
0
1
0
0
1
0
FC4
Mode
1
AC Voltage Measurement
1
AC Current Measurement(µA)
1
AC Current Measurement(mA)
1
Manual AC Current Measurement(A)
0 Auto AC Current Measurement(A)
1
DC Voltage Measurement
1
DC Current Measurement(µA)
1
DC Current Measurement(mA)
1
Manual DC Current Measurement(A)
0
Auto DC Current Measurement(A)
1
Resistance Measurement
1
Resistance Measurement
1
Continuity Check
1
diode Measurement
0
Temperature(℉)
Ps. X means “don’t care”
The other combinations of FC1, FC2, FC3, and FC4 are for ADP modes. In ADP modes
, if FC5 is LOW, the minus sign on the LCD panel will not be displayed. And if KEY pin
is floating, the buzzer beeps when the input signal is overflow. The ADP mode function is
summarized below.
FC1
1
1
1
1
FC2
1
1
0
0
FC3
1
0
0
1
FC4
0
0
0
0
Mode
ADP0
ADP1
ADP2
ADP3
Note: Temperature measurement mode takes input signal from ADP pin. In temperature
measurement mode, VBAR pin is used to control the right most digit point on the
LCD panel. When VBAR is LOW, this digit point is displayed.
3. Push function
3.1 HOLD
HOLD mode makes the meter stop updating the LCD panel. This mode can be nested in
most of the special modes. Enabling HOLD function in automatic mode makes the
meter switch to manual mode, but the full scale range remains the same. HOLD function
can be cancelled by changing the measurement mode, pressing RANGE, or push HOLD
again.
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3 1/2 AUTO DMM
3.2 Range
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.
Automatic
Mode
1 push < 1 sec
Manual
Mode
1 push > 1 sec
Range up
1 push < 1 sec
Measurement Mode
Auto
Manual
V(DC/AC)
VR2 – VR5 VRi
→
VRi
+
1,
VR5 → VR1
µA(DC/AC)
R1 – R2
R1 → R2,
R2 → R1
mA
R1－R2
R1 → R2
(AC/DC)
R2 → R1
Auto A(DC/AC)
R1 – R2
R1 → R2,
R2 → R1
A(DC/AC)
fixed
fixed
ORi
→
Ω
OR1- OR6 ORi + 1,
OR6 → OR1
Continuity
fixed
fixed
Diode
Fixed
fixed
Control Range
Initial Range
200.0mV – 2000V
2.000V
200.0µA - 2000µA
200.0µA
20.00mA –
200.0mA
20.00mA
2.000A – 20.00A
2.000A
20.00A
20.00A
200.0Ω – 20.00MΩ
200.0Ω
200.0Ω
2.000V
200.0Ω
2.000V
Note: Pushing RANGE resets all existing special modes.
3.3 KEY
See Section “Measurement Mode Switching” for the function of this pin.
4. Serial Data Output
The serial data sent to SDO pin twice every A/D conversion cycle. The data format
complies with JIS 7Bits transmission code with a baud rate of 19230. The host can use
RS232 interface to read the data. A single data packet includes a start bit (always 0), 7
data bits, an odd parity check bit, and a stop bit (always 1). The high and low voltage
levels correspond to DGND and V- respectively. SDO remains at 1 (high) when it is
inactive. Hence the start bit (0) could be used as the triggering signal to begin the
reading process. The following figure shows the data format of a single packet. The
LSB is sent first and the MSB is sent last.
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3 1/2 AUTO DMM
single package
0V
-3V
0
D0 ~D6
LSB
p 1
P
MSB
One data block consists of 11 packets, or 110 bits. The following figure shows the
format of a data block. The range packet indicates the full scale range of the meter.
Digit 3 through digit 0 are just the digits on the LCD panel. The function packet
indicates the measurement mode of the meter. Status, option 1 and option 2 give the
status of the meter. CR and LF are delimiters used to separate the blocks.
All
package
p 1 0
0
range
p 1 0
digit3
p 1 0
0
digit1
digit0
p 1 0
p 1 0
CR
p 1
function
p 1
option2
option1
status
0
digit2
p 1 0
p 1 0
0
p 1
p 1
LF
The meter always outputs the current input value to the serial port in spite of HOLD
mode. Each block is repeated twice in one conversion cycle. The detailed data format of
each packet is listed below.
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4.1 FUNCTUON
This packet indicates the measurement mode of the meter. The following table
summarizes the transmitted code for each mode. Note that the encoding of this packet is
different from the encoding of FC1-FC4 switch.
Code
0111011
0111101
0111111
0110000
0111001
0110011
0110101
0110001
0110100
0111110
0111100
0111000
0111010
Measurement Mode
Voltage
µA Current
mA Current
Auto A current
Manual A Current
Ω
Continuity
Diode
1*Temperature
ADP0
ADP1
ADP2
ADP3
Note: 1*.The judge bit in the Status packet determines whether the unit is Celcius or
Fahrenheit.
4.2 RANGE
This packet indicates the full scale range of the meter. When the meter operates in
continuity mode, diode mode, or current (A) mode, this packet is always 0110000 since
the full scale range in these modes are fixed. The following table lists the code for each
range in each measurement mode.
Code
0110000
0110001
0110010
0110011
0110100
0110101
0110110
V
2.000V
20.00V
200.0V
2000V
200.0mV
mA
20.00mA
200.0mA
µA
200.0µA
2000µA
Auto A
2.000 A
20.00 A
Ω
200.0Ω
2.000KΩ
20.00KΩ
200.0KΩ
2.000MΩ
20.00MΩ
4.3 DIGIT 3 – DIGIT 0
Digit 3 is the most significant digit on the LCD panel, and digit 0 is the least significant
digit. When the LCD panel shows OL, the serial port outputs 2000.
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Digit
0
1
2
3
4
5
6
7
8
9
Code
0110000
0110001
0110010
0110011
0110100
0110101
0110110
0110111
0111000
0111001
Because the cycle time of measurement for continuity/diode mode is only 50ms, the
least significant digit may not be accurate.
4.4 STATUS
The format of this shown below. The Judge field is meaningful only when the Function
packet indicates Temperature mode. In Temperature mode, judge is 1 if the unit is ℃
and is 0 of the unit is ℉ . Sign field indicates whether the minus sign on the LCD
panel is on or off. BATT field is one of battery low condition is true. OL indicates input
overflow.
0
BIT 6
1
BIT 5
1
BIT 4
Judge
BIT 3
Sign
BIT 2
BATT
BIT1
OL
BIT 0
1
BIT 4
HOLD
BIT 3
0
BIT 2
0
BIT1
0
BIT 0
4.5 OPTION 1
This packet is not used.
0
BIT 6
1
BIT 5
If Hold field is 1, Hold function is active. Hold function will not influence Digital 3~0
which is related to current measured value.
4.6 OPTION 2
This packet contains information on the operation mode of the meter. The format is
shown below. The DC field indicates that the meter operates in DC measurement mode,
either voltage or current. The AC field indicates that the meter operates in AC
measurement mode, either voltage or current. The AUTO field is set to one if the meter
operates in automatic mode, and is set to zero when the meter operates in manual mode.
0
BIT 6
1
BIT 5
1
BIT 4
DC
BIT 3
14
AC
BIT 2
AUTO
BIT1
0
BIT 0
11/01/05
ES51981
3 1/2 AUTO DMM
4.7 CR
Carrage return. The transmitted code is 0001101.
4.8 LF
Line feed. The transmitted code is 0001010.
5. Miscellaneous
The conditions which the meter turns on the buzzer include:
(1) Changing measurement mode generates one beep.
(2) Pressing any of the push junctions 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 25Ω(0.25V)
(6) Auto power off generates a 2KHz beep which lasts for 1.5 seconds.
The following figures shows 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
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ES51981
3 1/2 AUTO DMM
5.1 LCD Panel
1
BATT AUTO MANU
DC
AC
HOLD
℃ ℉
µ2 m2 V A
APO
MKΩ
RS232
SEG01 SEG02 SEG03 SEG04 SEG05 SEG06 SEG07 SEG08
BP1
BATT
DC
AUTO MANU
A3
B3
HOLD
A2
BP2
AC
F4
A4
B4
F3
G3
F2
B2
BP3
APO
—
G4
C4
E3
C3
E2
G2
BP4
RS232
E4
D4
P3
D3
P2
D2
C2
SEG09 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15
BP1
V
A
m2
u2
℃
BP2
F1
A1
B1
M
×
×
℉
BP3
E1
G1
C1
×
×
×
×
BP4
P1
D1
K
Ω
×
×
×
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ES51981
3 1/2 AUTO DMM
5.2 LCD Backplane Waveform
V- +3.1
VV- +3.1
VV- +3.1
VV- +3.1
VV- +3.1
V-
5.3 LCD display on condition
LCD Annunciator
V
Condition
In voltage measurement mode, and diode measurement mode.
A
In current measurement mode.
Ω
In resistance measurement mode, and continuity mode.
In continuity check mode.
In diode mode.
DC
In DC voltage or DC current mode.
AC
In AC voltage or AC current mode.
AUTO
When automatic full scale range selection is enabled.
MANU
In manual mode.
HOLD
When HOLD function is enabled.
m2
In voltage or current measurement mode and the full scale range is in the order of 10-3.
u2
In current measurement mode and the full scale range id in the order of uA.
M
In resistance measurement mode and the full scale range is in the order of MΩ
K
In resistance measurement mode and the full scale range is in the order of KΩ
℃
In temperature measurement mode and when the unit is ℃
℉
In temperature measurement mode and when the unit is ℉
APO
-
When auto power off function is enabled.
In voltage or current measurement mode and when the input is negative.
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ES51981
3 1/2 AUTO DMM
5.4 Operating Timing
ES51981 incorporates a dual slope ADC with four phases: ZI, AZ, INT and DINT.
The timing of each phase is listed below.
*Voltage /ohm/ADP measurement:
Phase
ZI
AZ
INT
DINT
Time
100ms
100ms
100ms
200ms
Ps. In the voltage and ohm measurement with auto mode, if the range is changed,
the internal clock rate will increase ten times and the new measurement cycle
becomes 1/10 times of the original cycle until the range is stable.
*Current mode
Phase
ZI
AZ
INT
DINT
Time
100ms
100ms
100ms
100ms
*Continuity/diode measurement
Phase
ZI
AZ
INT
DINT
Time
10ms
10ms
10ms
20ms
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ES51981
3 1/2 AUTO DMM
6.Test circuit
1. Voltage test
4.Current test
AGND
OVSG
100
1K
10K
101K
1.11M
D2
D1 1.0u
0.47u
1.0u
OR1
VR5
VR4
VR3
VR2
ADO
88M
ADI
ACVL
ACVH
TEST5
0.1u
15K
10K
15K
5K
0.005
20A
0.045
0.45
2A
mA
4.5
A
V
R
1
V
R
mA
45
mA
uA
AGND
SGND
100K
uA
uA
IVSH
100K
IVSL
450
10M
-100mV
Voltage input
5.ADP test
2.Resistor test
VA+
OVX
Z1
6V
Z2
100
100
1K
10K
101K
1.11M
100K
ADPin-
OVH
OVSG
VAADP
-100mV
ADPin+
PTC
1.5K
SGND
AGND
OR1
VR5
VR4
VR3
VR2
SGND
AGND
3.Diode test
6. Low battery
AGND
Z1
6V
Z2
100
9V
OVH
BA
PTC
1.5K
10M
1.11M
680K
TT
VR1
270K
LBAT9
0.1u AGND
V-
0V
VR2
OVSG
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11/01/05
ES51981
3 1/2 AUTO DMM
7.Application circuit
7.5V
5.6V ZI
0.1u
+
450
uA
uA
mA
10u
+
0.1u
-3V
0.1u
HOLD
RANGE
SLACDC
KEY
FC5
FC4
FC3
FC2
FC1
NC
C+
CNC
SDO
LBAT9
VVDGND
AGND
AGND
uA
4.7u
3V
10M
100K
-3V
-3V
Note: In order to prevent IC from damaging by inappropriate operation, the Zener
diodes MUST be required as protection.
20
11/01/05
-3V
Display
20K
(50)SEG13
SEG14
NC
SEG15
BKLIT
RS232
NC
NC
SLEEP
NC+
(40)NCNC
NC
VBAR
NC
VR1
SGND
ADP
VAVA+
+
4MHz
LCD
NC
BKOUT
NC
XTAL
NC
OSC1
OSC2
NC
BUZOUT
BUZIN
NC
ANNUNC
BP1
BP2
BP3
BP4
SEG01
SEG02
SEG03
SEG04
SEG05
SEG06
SEG07
SEG08
SEG09
SEG10
SEG11
SEG12
NC
NC
NC
V+
V+
4.5 mA
NC
mA
CL+
0.1u
CLA
0.45 2A
0.22u
CIL
0.1u
0.045 20A
100K CAZL
BUFL
0.005
IVSH(10)
100K
IVSL
SGND
100K
110pF
100 OVX
100K
OVH
1.5K
OVSG
R
PTC
NC
100
OR1
1K
Zener 6V
VR5
10K
101K VR4
VR3
1.11M
VR2(20)
10K
TEST5
ACVL
5K
ACVH
NC
15K
15K 0.1u
ADI
1u
1u
NC
88M
D1
D2 0.47u
ADO
NC
91K
VRH
1u
VR(30)
45
ES51981
3 1/2 AUTO DMM
Package
1
100 Pin QFP Package
2
Dimension Paramenters
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11/01/05