Small-Sized Current Sensor
CQ-121E, CQ-131E
■Small-sized open loop current transducer using Linear Hall
Effect IC
■Simple structure and few parts
■The primary conductor and the Hall Effect IC are isolated
electrically
■The amplifier is unnecessary.It is possible to connect to
micro-computer or AD converter directly.
■Small-size 8（D）×20（W）×19（H）
■Supply voltage range 3〜5.5V
■Ratiometric analog output
■Quick response Typ.3μs
■Supply current Typ.9mA
■Operating Temperature Range −30〜80℃
■In accordance with IEC standards
Features
Principles and Configration of Current Transducer
Others
1:Vcc
3:Out
2:Gnd
●Generating the magnetic flux
density outside the primary
conductor,when the current is
biased in the primary conductor.
●Generating the parallel
magnetic field inside the
core.
Generating the
magnetic flux
density inside
GAP,which is
proportionate
to current.
●Inserting Linear Hall Effect IC
into GAP.
Principles of current sensing
Configration of CQ-121E,131E Functional Block Diagram
Linear Hall Effect IC
Core
Primary Conductor
Sensed Current
Generating the
voltage which is
proportionate to
magnetic flux
density.
◆Frequently Asked Questions
Q1: How much is sensed current resolution?
A1: CQ-121E is about 100mA, CQ-131E is about 250mA.
Q2: How much is maximum current?
A2: "Maximum DC continuous current is 30A.
Linearity error ±1% of CQ-121E is guaranteed between -25 and 25A.
And that of CQ-131E is between -50 and 50A."
◆Absolute Maximum Ratings（Ta=25℃）
CQ-121E, 131E
Item Symbol Limit Unit
Maximum Input Voltage
Maximum Output Current
Operating Temp Range
Storage Temp Range
Vccmax
Iomax
Topr
Tstg
6
±1.2
−30 〜 80
−30 〜 85
V
mA
℃
℃
Sensitivity
rank
Color of
label
Typical
sensitivity
（mV/A）
Variation
(%)
Sensitivity range（mV/A）
B
C
D
Green
Blue
Yellow
55.0
59.9
65.3
60.7
66.1
72.0
57.85
63.00
68.65
±4.9
±4.9
±4.9
◆Recommended operating condition（Ta= 25℃）
CQ-121E, 131E
Item Min Max Unit
Supply voltage
Output current
3.0
−1
Symbol
Vcc
Io
Typ
5.0 5. 5
1
V
mA
◆
Electrical specifications for current sensing
（Ta=25℃, Vcc=5V）
CQ-121E
Item
Symbol
Min Typ
Sensitivity
Linearity error
Imax
Iin
Ins
Vh
ρ
−30
−25
−30
55
−1
63.5
Max
30
25
30
72
1
Unit
A
A
A
mV/A
%F.S.
Remarks
CQ-131E
Item
Symbol
Min Typ
Imax
Iin
Ins
Vh
ρ
−30
−50
−60
24
−1
27
Max
30
50
60
30
1
Unit
A
A
A
mV/A
%F.S.
Remarks
◆Electrical specifications（Ta=25℃, Vcc=5.0V）
CQ-121E, 131E
Item
Symbol
Min Typ
Supply current
Offset voltage
Note1）
Response time
Note2）
Frequency responseNote2）
Isolation voltage
Icc
Vof
Trr
f
Vhd
Vofd
2.35
50
−5
−0.5
1.5
500
9
2.5
3
100
Max
12
2.65
5
5
0.5
Unit
mA
V
μsec
kHz
%
mV/℃
kV
MΩ
Remarks
Without load
Iin=0
Iin=0
500V（DC）
Min Max
CQ-131E
B
C
D
Green
Blue
Yellow
24.0
25.7
27.7
26.3
28.3
30.3
25.15
27.00
28.85
±4.6
±4.8
±4.0
Electrical specifications of CQ-121E, 131E
Dimensions CQ-121E, CQ-131E
Note1）Design target
Note2）Slope in approximate straight line
Note3）Maximum differnce between approximate straight line and measured output voltage divided
by maximum rated current
Note1）Output voltage at 0（A）in approximate straight line
Note2）Design target
Note3）For reference only
CQ-121E
◆Sensitivity rank
8
±0.3
Primary conductor
φ1.6
±0.05
6.9
±0.15
1.27
±0.5
1.27
±0.5
6.9
±0.15
3.0
1.6
±0.5
0.25
3.4
±0.5
16.7
±0.3
6.15
±1.0
0.25
2.2
123
N P
Max.19
6.3
±0.2
4.4
±0.2
3.0
±0.2
20
±0.3
4.6
±0.5
2.2
±0.5
4.6
±0.5
0.2
±0.2
1.5
±1.0
Vcc
Label specifications
Label（White）
Resin fixed part
for primary conductor
Lot No
Color label for
sensitivity selection
Gnd
Out
Unit : mm
1
2
3
D
7
5
0.4
Maximum DC
sensed current
Rated sensed
current
Maximum sensed
current
Sensitivity
Linearity error
Maximum DC
sensed current
Rated sensed
current
Maximum sensed
current
Linearity error
guarantee range
Output unsaturation
rangeNote1）
Hysteresis is
includedNote3）
Note2）
Linearity error
guarantee range
Output unsaturation
rangeNote1）
Hysteresis is
includedNote3）
Note2）
Temperature drift
Note3）
Temperature coefficient
of Vof
Note3）
10%Decrease
point
The maximum error from
room temperature
60sec
（Commercial cycle）
Sensitivity
rank
Color of
label
Typical
sensitivity
（mV/A）
Variation
(%)
Sensitivity range（mV/A）
Min Max
Isolation
resistance
Note2）
◆Primary Sensed Current versus Output Voltage
CQ-121E CQ-131E
Characteristics of Current Transducer CQ-121E, CQ-131E（For reference only）
Step Response（CQ-121E, 131E）
◆Sensitivity versus Ambient Temparature ◆OA Output Voltage versus Ambient Temparature
◆
Supply Current versus Ambient Tenparature（CQ-121E, 131E）
◆Frequency Response
ASAHI KASEI MICRODEVICES CORPORATION
Headquarters
1-105 Kanda Jinbocho, Chiyoda-ku, Tokyo 101-8101, Japan
TEL : +81-3-3296-3961 FAX : +81-3-3296-3962
http://www.akm.com
5.1kΩ1000pF
March 2012
10
0
−10
−20
−30
−40
−50
0.01 0.1 1 10
Frequency（kHz）
Output change ratio（%）
100 1000−40 −20 0 20
Ambient Temparature（℃）
40 1008060
12
10
8
6
4
2
0
Supply Current（mA）
−60 −40 −20 0
Ambient Temparature（℃）
20 1008040 60
70
60
50
40
30
20
10
0
Sensitivity（mV/A）
−50 −40 −30 −20
Primary Sensed Current（A）
−10 503010 200 40
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
Output Voltage（V）
−40 −20 0 20
Ambient Temparature（℃）
40 10060 80
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Output Voltage（V）
−100−80 −60 −40
Primary Sensed Current（A）
−20 1006020 400 80
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
Output Voltage（V）
CQ-121E
CQ-131E
5μsec/div 5μsec/div
Primary sensed
Current
Output Voltage
（1V/div）
Primary
sensed
Current
Output
Voltage
（1V/div）
Vcc=5V
Vcc=4V
Vcc=3V
Vcc=5V
Vcc=4V
Vcc=3V
Vcc=5V
Vcc=4V
Vcc=3V
Vcc=5V
Vcc=4V
Vcc=3V
Vcc=5V
Vcc=4V
Vcc=3V
