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Current Transducer CAS series IPN = 6, 15, 25, 50 A
Ref: CAS 6-NP, CAS 15-NP, CAS 25-NP, CAS 50-NP
For the electronic measurement of current: DC, AC, pulsed..., with galvanic isolation
between the primary and the secondary circuit.
Features
● Closed loop (compensated) multi-range
current transducer
● Voltage output
● Single supply
● Isolated plastic case material recognized
according to UL 94-V0
● Compact design for PCB mounting.
Advantages
● Very low temperature coefcient of offset
●Very good dv/dt immunity
● LTS compatible footprint
● Reduced height.
Applications
● AC variable speed and servo motor drives
● Static converters for DC motor drives
● Battery supplied applications
● Uninterruptible Power Supplies (UPS)
● Switched Mode Power Supplies (SMPS)
● Power supplies for welding applications.
Standards
●EN 50178
●UL 508
● IEC 61010-1 (safety).
Application Domain
● Industrial.
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CAS series
Absolute maximum ratings
Stresses above these ratings may cause permanent damage. Exposure to absolute maximum ratings for extended periods may
degrade reliability.
Isolation characteristics
Parameter Symbol Unit Value Comment
RMS voltage for AC isolation test 50/60Hz/1 min VdkV 4.2
Impulse withstand voltage 1.2/50 µs VwkV 7.6
Partial discharge extinction voltage @ 10 pC (rms) VeV1000
Clearance distance (pri. - sec.) dCI mm 7.7 Shortest distance through
air
Creepage distance (pri. - sec.) dCp mm 7.7 Shortest path along device
body
Creepage distance (pri. .- sec.) -mm 6.3 When mounted on PCB
with recommended layout
Case material - - V0 according
to UL 94
Comparative tracking index CTI V600
Application example - - 300 V CAT III
PD2
Reinforced isolation, non
uniform eld according to
EN 50178, EN 61010
Application example - - 600 V CAT III
PD2
Simple isolation, non
uniform eld according to
EN 50178, EN 61010
According to UL 508:
primary potential involved in Volts RMS AC or DC -V600 For use in a pollution
degree 2 environment
Environmental and mechanical characteristics
Parameter Symbol Unit Min Typ Max Comment
Ambient operating temperature TA°C -40 85
Ambient storage temperature TS°C -55 105
Mass mg 9
Standards EN 50178, IEC 60950-1, IEC 61010-1, IEC 61326-1, UL 508
Parameter Symbol Unit Value
Supply voltage VCV 7
Primary conductor temperature °C 110
Maximum primary current IP max A20 x IPN
ESD rating, Human Body Model (HBM) kV 4
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CAS series
Electrical data CAS 6-NP
At TA = 25°C, VC = + 5 V, NP = 1 turn, RL = 10 kΩ, unless otherwise noted.
Parameter Symbol Unit Min Typ Max Comment
Primary nominal current rms IPN A 6
Primary current, measuring range IPM A-20 20
Number of primary turns NP-1,2,3
Supply voltage VCV4.75 55.25
Current consumption ICmA 15 + 20 + NS = 1731 turns
Output voltage VOUT V0.375 4.625
Output voltage @ IP = 0 A VOUT V2.5
Electrical offset voltage VOE mV -10.4 10.4 100% tested
VOUT - 2.5 V
Electrical offset current
referred to primary IOE A-0.1 0.1 100% tested
Temperature coefcient of VOUT
@ IP = 0 A TCVOUT ppm/K ±10 ±80 ppm/K of 2.5 V
- 40°C .. 85°C
Theoretical sensitivity Gth mV/A 104.2 625 mV/ IPN
Sensitivity error εG%-0.7 0.7 100% tested
Temperature coefcient of GTCG ppm/K ±40 - 40°C .. 85°C
Linearity error εL% of IPN -0.1 0.1
Magnetic offset current (10 x IPN)
referred to primary IOM A-0.1 0.1
Output current noise (spectral
density) rms 100 .. 100 kHz
referred to primary
ino µA/Hz½36 RL = 1 kΩ
Peak-peak output ripple at
oscillator frequency
f = 450 kHz (typ.)
-mV 40 160 RL = 1 kΩ
Reaction time @ 10 % of IPN tra µs 0.3 RL = 1 kΩ
di/dt = 18 A/µs
Response time @ 90 % of IPN trµs 0.3 RL = 1 kΩ
di/dt = 18 A/µs
Frequency bandwidth (± 1 dB) BW kHz 200 RL = 1 kΩ
Frequency bandwidth (± 3 dB) BW kHz 300 RL = 1 kΩ
Overall accuracy XG% of IPN 2.5
Overall accuracy @ TA = 85°C XG% of IPN 4.6
Accuracy X% of IPN 0.8
Accuracy @ TA = 85°C X% of IPN 3.0
IP (mA)
NS
IP (mA)
NS
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CAS series
Electrical data CAS 15-NP
At TA = 25°C, VC = + 5 V, NP = 1 turn, RL = 10 kΩ, unless otherwise noted.
Parameter Symbol Unit Min Typ Max Comment
Primary nominal current rms IPN A15
Primary current, measuring range IPM A-51 51
Number of primary turns NP-1,2,3
Supply voltage VCV4.75 55.25
Current consumption ICmA 15 + 20 + NS = 1731 turns
Output voltage VOUT V0.375 4.625
Output voltage @ IP = 0 A VOUT V2.5
Electrical offset voltage VOE mV -7.1 7.1 100% tested
VOUT - 2.5 V
Electrical offset current
referred to primary IOE A-0.17 0.17 100% tested
Temperature coefcient of VOUT
@ IP = 0 A TCVOUT ppm/K ±7.5 ±70 ppm/K of 2.5 V
- 40°C .. 85°C
Theoretical sensitivity Gth mV/A 41.67 625 mV/ IPN
Sensitivity error εG
%-0.7 0.7 100% tested
Temperature coefcient of GTCG ppm/K ±40 - 40°C .. 85°C
Linearity error εL% of IPN -0.1 0.1
Magnetic offset current (10 x IPN)
referred to primary IOM A-0.1 0.1
Output current noise (spectral
density) rms 100 Hz .. 100 kHz
referred to primary
ino µA/Hz½90 RL = 1 kΩ
Peak-peak output ripple at
oscillator frequency
f = 450 kHz (typ.)
-mV 15 60 RL = 1 kΩ
Reaction time @ 10 % of IPN tra µs 0.3 RL = 1 kΩ
di/dt = 44 A/µs
Response time @ 90 % of IPN trµs 0.3 RL = 1 kΩ
di/dt = 44 A/µs
Frequency bandwidth (± 1 dB) BW kHz 200 RL = 1 kΩ
Frequency bandwidth (± 3 dB) BW kHz 300 RL = 1 kΩ
Overall accuracy XG% of IPN 1.9
Overall accuracy @ TA = 85°C XG% of IPN 3.9
Accuracy X% of IPN 0.8
Accuracy @ TA = 85°C X% of IPN 2.7
IP (mA)
NS
IP (mA)
NS
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CAS series
Electrical data CAS 25-NP
At TA = 25°C, VC = + 5 V, NP = 1 turn, RL = 10 kΩ, unless otherwise noted.
Parameter Symbol Unit Min Typ Max Comment
Primary nominal current rms IPN A25
Primary current, measuring range IPM A-85 85
Number of primary turns NP-1,2,3
Supply voltage VCV4.75 55.25
Current consumption ICmA 15 + 20 + NS = 1731 turns
Output voltage VOUT V0.375 4.625
Output voltage @ IP = 0 A VOUT V2.5
Electrical offset voltage VOE mV -6.25 6.25 100% tested
VOUT - 2.5 V
Electrical offset current
referred to primary IOE A-0.25 0.25 100% tested
Temperature coefcient of VOUT
@ IP = 0 A TCVOUT ppm/K ±6.5 ±60 ppm/K of 2.5 V
- 40°C .. 85°C
Theoretical sensitivity Gth mV/A 25 625 mV/ IPN
Sensitivity error εG
%-0.7 0.7 100% tested
Temperature coefcient of GTCG ppm/K ±40 - 40°C .. 85°C
Linearity error εL% of IPN -0.1 0.1
Magnetic offset current (10 x IPN)
referred to primary IOM A-0.1 0.1
Output current noise (spectral
density) rms 100 Hz .. 100 kHz
referred to primary
ino µA/Hz½150 RL = 1 kΩ
Peak-peak output ripple at
oscillator frequency
f = 450 kHz (typ.)
-mV 10 40 RL = 1 kΩ
Reaction time @ 10 % of IPN tra µs 0.3 RL = 1 kΩ
di/dt = 68 A/µs
Response time @ 90 % of IPN trµs 0.3 RL = 1 kΩ
di/dt = 68 A/µs
Frequency bandwidth (± 1 dB) BW kHz 200 RL = 1 kΩ
Frequency bandwidth (± 3 dB) BW kHz 300 RL = 1 kΩ
Overall accuracy XG% of IPN 1.8
Overall accuracy @ TA = 85°C XG% of IPN 3.5
Accuracy X% of IPN 0.8
Accuracy @ TA = 85°C X% of IPN 2.5
IP (mA)
NS
IP (mA)
NS
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CAS series
Electrical data CAS 50-NP
At TA = 25°C, VC = + 5 V, NP = 1 turn, RL = 10 kΩ, unless otherwise noted.
Parameter Symbol Unit Min Typ Max Comment
Primary nominal current rms IPN A50
Primary current, measuring range IPM A-150 150
Number of primary turns NP-1,2,3
Supply voltage VCV4.75 55.25
Current consumption ICmA 15 + 20 + NS = 966 turns
Output voltage VOUT V0.375 4.625
Output voltage @ IP = 0 A VOUT V2.5
Electrical offset voltage VOE mV -5.8 5.8 100% tested
VOUT - 2.5 V
Electrical offset current
referred to primary
IOE A-0.46 0.46 100% tested
Temperature coefcient of VOUT
@ IP = 0 A TCVOUT ppm/K ±6 ±60 ppm/K of 2.5 V
- 40°C .. 85°C
Theoretical sensitivity Gth mV/A 12.5 625 mV/ IPN
Sensitivity error εG
%-0.7 0.7 100% tested
Temperature coefcient of GTCG ppm/K ±40 - 40°C .. 85°C
Linearity error εL% of IPN -0.1 0.1
Magnetic offset current (10 x IPN)
referred to primary IOM A-0.1 0.1
Output current noise (spectral
density) rms 100 Hz .. 100 kHz
referred to primary
ino µA/Hz½300 RL = 1 kΩ
Peak-peak output ripple at
oscillator frequency
f = 450 kHz (typ.)
-mV 520 RL = 1 kΩ
Reaction time @ 10 % of IPN tra µs 0.3 RL = 1 kΩ
di/dt = 100 A/µs
Response time @ 90 % of IPN trµs 0.3 RL = 1 kΩ
di/dt = 100 A/µs
Frequency bandwidth (± 1 dB) BW kHz 200 RL = 1 kΩ
Frequency bandwidth (± 3 dB) BW kHz 300 RL = 1 kΩ
Overall accuracy XG% of IPN 1.7
Overall accuracy @ TA = 85°C XG% of IPN 3.4
Accuracy X% of IPN 0.8
Accuracy @ TA = 85°C X% of IPN 2.5
IP (mA)
NS
IP (mA)
NS
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CAS series
Typical performance characteristics CAS 6-NP
Figure 1: Linearity error Figure 2: Frequency response
Figure 3: Step response Figure 4: Step response
Figure 5: Input referred noise Figure 6: dv/dt
-0.1
-0.05
0
0.05
0.1
-6 0 6
IP (A)
Linearity error (% of I
PN)
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
100 1000 10000 100000 1000000
Frequency (Hz)
Relative Sensitivity (dB)
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
Phase (°)
Relative
Sensitivity
Phase
-1
0
1
2
3
4
5
6
7
-0.5 00.5 11.5 2
t (µs)
IP (A)
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
VOUT (V)
IP
VOU T
IP = 6 A
-800
-600
-400
-200
0
200
400
600
800
-1 01234 5
t (µs)
Primary Voltage VP (V)
2.4
2.6
2.8
3.0
3.2
3.4
3.6
VOUT (V)
VP
VOU T
20 kV/μs
-1
0
1
2
3
4
5
6
7
-2 0 2 4 6 8 10
t (µs)
IP (A)
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
VOUT (V)
IP
VOU T
IP = 6 A
1
10
100
1000
10000
1. E+1 1. E+2 1 .E+3 1. E+4 1. E+5 1 .E+6 1 .E+7
Frequency (Hz)
ino (μA/Hz
½)
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CAS series
Typical performance characteristics CAS 15-NP
Figure 7: Linearity error Figure 8: Frequency response
Figure 9: Step response Figure 10: Step response
Figure 11: Input referred noise Figure 12: dv/dt
-0.1
-0.05
0
0.05
0.1
-15 015
IP (A)
Linearity error (% of I
PN)
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
100 1000 10000 100000 1000000
Frequency (Hz)
Relative Sensitivity (dB)
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
Phase (°)
Relative
Sensitivity
Phase
-800
-600
-400
-200
0
200
400
600
800
-1 01234 5
t (µs)
Primary Voltage VP (V)
2.4
2.6
2.8
3.0
3.2
3.4
3.6
VOUT (V)
VP
VOU T
20 kV/μs
-2.5
0
2.5
5
7.5
10
12.5
15
17.5
-0.5 00.5 11.5 2
t (µs)
IP (A)
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
VOUT (V)
IP
VOU T
IP = 15 A
-2.5
0
2.5
5
7.5
10
12.5
15
17.5
-2 0 2 4 6 8 10
t (µs)
IP (A)
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
VOUT (V)
IP
VOU T
IP = 15 A
1
10
100
1000
10000
1. E+1 1. E+2 1. E+3 1. E+4 1 .E+5 1. E+6 1 .E+7
Frequency (Hz)
ino (μA/Hz
½)
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CAS series
Typical performance characteristics CAS 25-NP
Figure 13: Linearity error Figure 14: Frequency response
Figure 15: Step response Figure 16: Step response
Figure 17: Input referred noise Figure 18: dv/dt
-0.1
-0.05
0
0.05
0.1
-25 025
IP (A)
Linearity error (% of I
PN)
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
100 1000 10000 100000 1000000
Frequency (Hz)
Relative Sensitivity (dB)
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
Phase (°)
Relative
Sensitivity
Phase
IP = 25 A
-800
-600
-400
-200
0
200
400
600
800
-1 01234 5
t (µs)
Primary Voltage VP (V)
2.4
2.6
2.8
3.0
3.2
3.4
3.6
VOUT (V)
VP
VOU T
20 kV/μs
-4.2
0.0
4.2
8.3
12.5
16.7
20.8
25.0
29.2
-0.5 00.5 11.5 2
t (µs)
IP (A)
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
VOUT (V)
IP
VOU T
IP = 25 A
-4.2
0.0
4.2
8.3
12.5
16.7
20.8
25.0
29.2
-2 0246810
t (µs)
IP (A)
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
VOUT (V)
IP
VOU T
IP = 25 A
1
10
100
1000
10000
1. E+1 1. E+2 1. E+3 1. E+4 1 .E+5 1. E+6 1 .E+7
Frequency (Hz)
ino (μA/Hz
½)
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CAS series
Typical performance characteristics CAS 50-NP
Figure 19: Linearity error Figure 20: Frequency response
Figure 21: Step response Figure 22: Step response
Figure 23: Input referred noise Figure 24: dv/dt
-0.1
-0.05
0
0.05
0.1
-50 050
IP (A)
Linearity error (% of I
PN)
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
100 1000 10000 100000 1000000
Frequency (Hz)
Relative Sensitivity (dB)
-9
-8
-7
-6
-5
-4
-3
-2
-1
0
1
Phase (°)
Relative
Sensitivity
Phase
IP = 50 A
-800
-600
-400
-200
0
200
400
600
800
-1 01234 5
t (µs)
Primary Voltage VP (V)
2.4
2.6
2.8
3.0
3.2
3.4
3.6
VOUT (V)
VP
VOU T
20 kV/μs
-8.3
0.0
8.3
16.7
25.0
33.3
41.7
50.0
58.3
-0.5 00.5 11.5 2
t (µs)
IP (A)
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
VOUT (V)
IP
VOU T
IP = 50 A
-8.3
0.0
8.3
16.7
25.0
33.3
41.7
50.0
58.3
-2 0 2 4 6 8 10
t (µs)
IP (A)
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
VOUT (V)
IP
VOU T
IP = 50 A
1
10
100
1000
10000
1. E+1 1. E+2 1. E+3 1. E+4 1. E+5 1. E+6 1. E+7
Frequency (Hz)
ino (μA/Hz
½)
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CAS series
Maximum continuous DC primary current
Figure 25: IP vs TA for CAS 6-NP Figure 26: IP vs TA for CAS 15-NP
Figure 27: IP vs TA for CAS 25-NP Figure 28: IP vs TA for CAS 50-NP
The maximum continuous DC primary current plot shows the boundary of the area for which all the following conditions are
true:
-IP < IPM
- Junction temperature Tj < 125 °C
- Primary conductor temperature < 110 °C
- Resistor power dissipation < 0.5 x rated power
Frequency derating
Figure 29: Maximum RMS AC primary current / maximum DC primary current vs frequency
CAS 6-NP
0
5
10
15
20
25
30
35
40
020 40 60 80 100 120
TA (°C)
IP (A)
CAS 15-NP
0
10
20
30
40
50
60
70
80
90
020 40 60 80 100 120
TA (°C)
IP (A)
CAS 25-NP
0
10
20
30
40
50
60
70
80
90
020 40 60 80 100 120
TA (°C)
IP (A)
CAS 50-NP
0
20
40
60
80
100
120
140
160
020 40 60 80 100 120
TA (°C)
IP (A)
AC Derating
10
100
1M
1k
10k
100k
0
0.25
0.5
0.75
1
1.25
f (Hz)
max RMS AC current /
max DC current
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CAS series
Ampere-turns and amperes
The transducer is sensitive to the primary current linkage
QP (also called ampere-turns).
 Q
P=NPIP(At)
Where NPIP the number of primary turn (1, 2 or 3
depending on the connection of the primary
jumpers)
Caution: As most applications will use the transducer with
only one single primary turn (NP = 1), much of this datasheet
is written in terms of primary current instead of current
linkages. However, the ampere-turns (A-t) unit is used to
emphasis that current linkages are intended and applicable.
Transducer simplied model
The static model of the transducer at temperature TA is:
VOUT = G QP + error
In which error =
VOE + VOT (TA) + εG ·QP·G + εL(QPmax)·QPmax·G + TCG·(TA-25)·QP·G
With: QP = NPIP :the input ampere-turns (At)
Please read above warning.
QPmax :the maxi input ampere-turns that have
been applied to the transducer (At)
VOUT :the secondary voltage (V)
TA :the ambient temperature (°C)
VOE :the electrical offset voltage (V)
VOT(TA) :the temperature variation of VO at
temperature TA (V)
G :the sensitivity of the transducer (V/At)
ε
G :the sensitivity error
ε
L (QPmax) :the linearity error for QPmax
This model is valid for primary ampere-turns QP between
-QPmax and +QPmax only.
Performance parameters denition
Sensitivity and linearity
To measure sensitivity and linearity, the primary current (DC)
is cycled from 0 to IP, then to -IP and back to 0 (equally spaced
IP/10 steps).
The sensitivity G is dened as the slope of the linear
regression line for a cycle between ± IPN.
The linearity error εL is the maximum positive or negative
difference between the measured points and the linear
regression line, expressed in % of IPN.
Magnetic offset
The magnetic offset current IOM is the consequence of a
current on the primary side (“memory effect” of the
transducer’s ferro-magnetic parts). It is included in the
linearity gure but can be measured individually.
It is measured using the following primary current cycle.
IOM depends on the current value IP1.
Figure 30: Current cycle used to measure magnetic and
electrical offset (transducer supplied)
IP (DC)
-IP1
IP1
0 A
t1 t
t Ip(3)
t2
Ip(
3)
Gth
tVtV
IOUTOUT
OM
1
2
)()( 21 ⋅
−
=
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CAS series
Response and reaction times
The response time tr and the reaction time tra are shown in
gure 31.
Both depend on the primary current di/dt. They are measured
at nominal ampere-turns.
Figure 31: Response time tr and reaction time tra
Figure 32: Test connection
Electrical offset
The electrical offset voltage VOE can either be measured when
the ferro-magnetic parts of the transducer are:
● completely demagnetized, which is difcult to realize,
● or in a known magnetization state, like in the current cycle
shown in gure 30.
Using the current cycle shown in gure 30, the electrical offset
is:
The temperature variation VOT of the electrical offset voltage
VOE is the variation of the electrical offset from 25°C to the
considered temperature:
Note: the transducer has to be demagnetized prior to the
application of the current cycle (for example with a
demagnetization tunnel).
Overall accuracy
The overall accuracy at 25°C XG is the error in the - IPN .. + IPN
range, relative to the rated value IPN.
It includes:
● the electrical offset VOE
●the sensitivity error εG
● the linearity error εL (to IPN)
The magnetic offset is part of the overall accuracy. It is
taken into account in the linearity error gure provided the
transducer has not been magnetized by a current higher than
IPN.
Performance parameters denition (continued)
2
)()( 21 tVtV
VOUTOUT
OE
+
=
)25()()( CVTVTV
OEOEOT
°−=
t
ra
V
OUT
t
r
90 %
10 %
t
100 %
I
p
I
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8March2012/version 7 LEM reserves the right to carry out modications on its transducers, in order to improve them, without prior notice www.lem.com
CAS series
Output VOUT
The output VOUT has a very low output impedance of
typically 2 Ohms; it can drive 100 pF directly. Adding series
Rf = 100 Ohms allows much larger capacitive loads. Empirical
evaluation may be necessary to obtain optimum results.
The minimum load resistance on VOUT is 1 kOhm.
Filtering and decoupling
Supply voltage VC
The uxgate oscillator draws current pulses of up to 30 mA
at a rate of ca. 900 kHz. Signicant 900 kHz voltage ripple
on VC can indicate a power supply with high impedance. At
these frequencies the power supply rejection ratio is low, and
the ripple may appear on the transducer output VOUT and
reference VREF. The transducer has internal decoupling
capacitors, but in the case of a power supply with high
impedance, it is advised to provide local decoupling (100 nF
or more, located close to the transducer).
Total Primary Resistance
The primary resistance is 0.72 mΩ per conductor
In the following table, examples of primary resistance
according to the number of primary turns.
Number of
primary turns
Primary
resistance
RP [ mW ]
Recommended
connections
10.24
10 9 8 OUT
IN 1 2 3
21.08
10 9 8 OUT
IN 1 2 3
3 2.16
10 9 8 OUT
IN 1 2 3
Application information
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CAS series
CAS Series, PCB footprint
Assembly on PCB
● Recommended PCB hole diameter 1.3 mm for primary pin
0.8 mm for secondary pin
● Maximum PCB thickness 2.4 mm
● Wave soldering prole maximum 260°C for 10 s
No clean process only.
Safety
This transducer must be used in limited-energy secondary circuits
according to IEC 61010-1.
This transducer must be used in electric/electronic equipment
with respect to applicable standards and safety requirements in
accordance with the manufacturer’s operating instructions.
Caution, risk of electrical shock
When operating the transducer, certain parts of the module can carry
hazardous voltage (eg. primary busbar, power supply).
Ignoring this warning can lead to injury and/or cause serious damage.
This transducer is a build-in device, whose conducting parts must be
inaccessible after installation.
A protective housing or additional shield could be used.
Main supply must be able to be disconnected.
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CAS series
Dimensions CAS Series (in mm. General linear tolerance ± 0.25 mm)
Connection