Current Transducer CASR series
IPN = 6, 15, 25, 50 A
Ref: CASR 6-NP, CASR 15-NP, CASR 25-NP, CASR 50-NP
For the electronic measurement of current: DC, AC, pulsed..., with galvanic isolation
between the primary and the secondary circuit.
Features
Applications
●● Closed loop (compensated) multi-range
●● AC variable speed and servo motor drives
current transducer
●● Static converters for DC motor drives
●● Voltage output
●● Battery supplied applications
●● Single supply
●● Uninterruptible Power Supplies (UPS)
●● Isolated plastic case material recognized
●● Switched Mode Power Supplies (SMPS)
according to UL 94-V0
●● Power supplies for welding applications
●● Compact design for PCB mounting.
●● Solar inverters.
Advantages
Standards
●● Very low temperature coefficient of offset
●● EN 50178
●● Very good dv/dt immunity
●● UL 508
●● LTSR compatible footprint
●● IEC 61010-1 (safety).
●● Reduced height
●● Reference pin with two modes: Ref IN and Ref OUT
●● Extended measuring range for unipolar measurement.
Application Domain
●● Industrial.
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CASR series
Absolute maximum ratings
Parameter
Symbol
Unit
Value
VC
V
7
°C
110
A
20 x IPN
kV
4
Supply voltage
Primary conductor temperature
Maximum primary current
IP max
ESD rating, Human Body Model (HBM)
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
RMS voltage for AC isolation test 50/60Hz/1 min
Vd
kV
4.1
Impulse withstand voltage 1.2/50 µs
Vw
kV
7.5
Partial discharge extinction voltage @ 10 pC (rms)
Ve
V
1000
Clearance distance (pri. - sec.)
dCI
mm
7.5
Shortest distance through
air
Creepage distance (pri. - sec.)
dCp
mm
7.5
Shortest path along device
body
Creepage distance (pri. .- sec.)
dCp
mm
6.2
When mounted on PCB
with recommended layout
-
-
V0 according
to UL 94
CTI
V
600
Application example
-
-
Reinforced isolation, non
300 V CAT III
uniform field according to
PD2
EN 50178, EN 61010
Application example
-
-
Simple isolation, non
600 V CAT III
uniform field according to
PD2
EN 50178, EN 61010
According to UL 508:
primary potential involved in Volts RMS AC or DC
-
V
Symbol
Unit
Min
Ambient operating temperature
TA
°C
-40
85
Ambient storage temperature
TS
°C
-55
105
Mass
m
g
Case material
Comparative tracking index
Comment
For use in a pollution
degree 2 environment
600
Environmental and mechanical characteristics
Parameter
Standards
Typ
Max
Comment
9
EN 50178, IEC 60950-1, IEC 61010-1, IEC 61326-1, UL 508
Page 2/18
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CASR series
Electrical data CASR 6-NP
At TA = 25°C, VC = + 5 V, NP = 1 turn, RL = 10 kΩ, internal reference, unless otherwise noted.
Parameter
Max
Comment
Unit
Primary nominal current rms
IPN
A
Primary current, measuring range
IPM
A
Number of primary turns
NP
-
Supply voltage
VC
V
Current consumption
IC
mA
Reference voltage @ IP = 0 A
VREF
V
2.495
External reference voltage
VREF
V
0
4
Output voltage
VOUT
V
0.375
4.625
Output voltage @ IP = 0 A
VOUT
V
Electrical offset voltage
VOE
mV
-5.3
5.3
100% tested
VOUT - VREF
Electrical offset current referred to
primary
IOE
mA
-51
51
100% tested
Temperature coefficient of VREF
TCVREF
ppm/K
±5
±50
Internal reference
Temperature coefficient of VOUT
@ IP = 0 A
TCVOUT
ppm/K
±6
±14
ppm/K of 2.5 V
- 40°C .. 85°C
Theoretical sensitivity
Gth
mV/A
104.2
Sensitivity error
εG
%
TCG
ppm/K
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/Hz½
20
Peak-peak output ripple at oscillator
frequency f = 450 kHz (typ.)
-
mV
40
Reaction time @ 10 % of IPN
tra
Response time @ 90 % of IPN
Temperature coefficient of G
Min
Typ
Symbol
6
-20
20
1,2,3
4.75
5
15 +
IP (mA)
NS
2.5
5.25
20 +
IP (mA)
NS
2.505
NS = 1731 turns
Internal reference
VREF
-0.7
625 mV/ IPN
0.7
100% tested
±40
- 40°C .. 85°C
RL = 1 kΩ
160
RL = 1 kΩ
µs
0.3
RL = 1 kΩ
di/dt = 18 A/µs
tr
µs
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
1.7
Overall accuracy @ TA = 85°C
XG
% of IPN
2.2
Accuracy
X
% of IPN
0.8
Accuracy @ TA = 85°C
X
% of IPN
1.4
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CASR series
Electrical data CASR 15-NP
At TA = 25°C, VC = + 5 V, NP = 1 turn, RL = 10 kΩ, internal reference, unless otherwise noted.
Parameter
Max
Comment
Unit
Primary nominal current rms
IPN
A
Primary current, measuring range
IPM
A
Number of primary turns
NP
-
Supply voltage
VC
V
Current consumption
IC
mA
Reference voltage @ IP = 0 A
VREF
V
2.495
External reference voltage
VREF
V
0
4
Output voltage
VOUT
V
0.375
4.625
Output voltage @ IP = 0 A
VOUT
V
Electrical offset voltage
VOE
mV
-2.21
2.21
100% tested
VOUT - VREF
Electrical offset current referred to
primary
IOE
mA
-53
53
100% tested
Temperature coefficient of VREF
TCVREF
ppm/K
±5
±50
Internal reference
Temperature coefficient of VOUT
@ IP = 0 A
TCVOUT
ppm/K
±2.3
±6
ppm/K of 2.5 V
- 40°C .. 85°C
Theoretical sensitivity
Gth
mV/A
41.67
Sensitivity error
εG
%
TCG
ppm/K
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/Hz½
20
Peak-peak output ripple at oscillator
frequency f = 450 kHz (typ.)
-
mV
15
Reaction time @ 10 % of IPN
tra
Response time @ 90 % of IPN
Temperature coefficient of G
Min
Typ
Symbol
15
-51
51
1,2,3
4.75
5
15 +
IP (mA)
NS
2.5
5.25
20 +
IP (mA)
NS
2.505
NS = 1731 turns
Internal reference
VREF
-0.7
625 mV/ IPN
0.7
100% tested
±40
- 40°C .. 85°C
RL = 1 kΩ
60
RL = 1 kΩ
µs
0.3
RL = 1 kΩ
di/dt = 44 A/µs
tr
µs
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
1.2
Overall accuracy @ TA = 85°C
XG
% of IPN
1.5
Accuracy
X
% of IPN
0.8
Accuracy @ TA = 85°C
X
% of IPN
1.2
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CASR series
Electrical data CASR 25-NP
At TA = 25°C, VC = + 5 V, NP = 1 turn, RL = 10 kΩ, internal reference, unless otherwise noted.
Parameter
Max
Comment
Unit
Primary nominal current rms
IPN
A
Primary current, measuring range
IPM
A
Number of primary turns
NP
-
Supply voltage
VC
V
Current consumption
IC
mA
Reference voltage @ IP = 0 A
VREF
V
2.495
External reference voltage
VREF
V
0
4
Output voltage
VOUT
V
0.375
4.625
Output voltage @ IP = 0 A
VOUT
V
Electrical offset voltage
VOE
mV
-1.35
1.35
100% tested
VOUT - VREF
Electrical offset current referred to
primary
IOE
mA
-54
54
100% tested
Temperature coefficient of VREF
TCVREF
ppm/K
±5
±50
Internal reference
Temperature coefficient of VOUT
@ IP = 0 A
TCVOUT
ppm/K
±1.4
±4
ppm/K of 2.5 V
- 40°C .. 85°C
Theoretical sensitivity
Gth
mV/A
25
Sensitivity error
εG
%
TCG
ppm/K
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/Hz½
20
Peak-peak output ripple at oscillator
frequency f = 450 kHz (typ.)
-
mV
10
Reaction time @ 10 % of IPN
tra
Response time @ 90 % of IPN
Temperature coefficient of G
Min
Typ
Symbol
25
-85
85
1,2,3
4.75
5
15 +
5.25
IP (mA)
I (mA)
20 + P
NS
NS
2.5
2.505
NS = 1731 turns
Internal reference
VREF
-0.7
625 mV/ IPN
0.7
100% tested
±40
- 40°C .. 85°C
RL = 1 kΩ
40
RL = 1 kΩ
µs
0.3
RL = 1 kΩ
di/dt = 68 A/µs
tr
µs
0.3
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
Overall accuracy @ TA = 85°C
XG
% of IPN
1.35
Accuracy
X
% of IPN
0.8
Accuracy @ TA = 85°C
X
% of IPN
1.15
RL = 1 kΩ
di/dt = 68 A/µs
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CASR series
Electrical data CASR 50-NP
At TA = 25°C, VC = + 5 V, NP = 1 turn, RL = 10 kΩ, internal reference, unless otherwise noted.
Parameter
Max
Comment
Unit
Primary nominal current rms
IPN
A
Primary current, measuring range
IPM
A
Number of primary turns
NP
-
Supply voltage
VC
V
Current consumption
IC
mA
Reference voltage @ IP = 0 A
VREF
V
2.495
External reference voltage
VREF
V
0
4
Output voltage
VOUT
V
0.375
4.625
Output voltage @ IP = 0 A
VOUT
V
Electrical offset voltage
VOE
mV
-0.725
0.725
100% tested
VOUT - VREF
Electrical offset current referred to
primary
IOE
mA
-58
58
100% tested
Temperature coefficient of VREF
TCVREF
ppm/K
±5
±50
Internal reference
Temperature coefficient of VOUT
@ IP = 0 A
TCVOUT
ppm/K
±0.7
±3
ppm/K of 2.5 V
- 40°C .. 85°C
Theoretical sensitivity
Gth
mV/A
12.5
Sensitivity error
εG
%
TCG
ppm/K
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/Hz½
20
Peak-peak output ripple at oscillator
frequency f = 450 kHz (Typ.)
-
mV
5
Reaction time @ 10 % of IPN
tra
Response time @ 90 % of IPN
Temperature coefficient of G
Min
Typ
Symbol
50
-150
150
1,2,3
4.75
5
15 +
5.25
IP (mA)
I (mA)
20 + P
NS
NS
2.5
2.505
NS = 966 turns
Internal reference
VREF
-0.7
625 mV/ IPN
0.7
100% tested
±40
- 40°C .. 85°C
RL = 1 kΩ
20
RL = 1 kΩ
µs
0.3
RL = 1 kΩ
di/dt = 100 A/µs
tr
µs
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
0.9
Overall accuracy @ TA = 85°C
XG
% of IPN
1.2
Accuracy
X
% of IPN
0.8
Accuracy @ TA = 85°C
X
% of IPN
1.1
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CASR series
0
-0.05
-0.1
-6
0
IP (A)
Figure 1: Linearity error
1000
10000 100000 1000000
Frequency (Hz)
Figure 2: Frequency response
3.2
7
3.2
6
3.1
6
3.1
3.0
5
3.0
2.9
4
IP = 6 A
3
2.8
IP (A)
4
VOUT (V)
7
5
IP (A)
Relative
Sensitivity
Phase
100
6
3
2.8
IP
2.7
2.6
1
VOUT
2.6
0
2.5
0
-1
2.4
-1
VOUT
-0.5
0
0.5
1
1.5
2.5
2.4
-2
2
0
2
4
6
8
10
t (µs)
t (µs)
Figure 3: Step response
Figure 4: Step response
10000
Primary Voltage VP (V)
800
1000
100
10
3.6
600
3.4
400
3.2
200
0
-200
VP
VOUT
VREF
-400
1
3.0
20 kV/μs
2.8
2.6
-600
-800
0.1
1.E+1 1.E+2 1.E+3 1.E+4 1.E+5 1.E+6 1.E+7
Frequency (Hz)
Figure 5: Input referred noise VOUT (V)
2.7
IP
1
½
2.9
IP = 6 A
2
2
ino (μA/Hz )
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
IP = 6 A
VOUT (V)
0.05
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
Phase (°)
0.1
Relative Sensitivity (dB)
Linearity error (% of IPN)
Typical performance characteristics CASR 6-NP
2.4
-1
0
1
2
3
4
5
t (µs)
Figure 6: dv/dt
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CASR series
Relative Sensitivity (dB)
0
-0.05
-0.1
-15
0
IP (A)
Relative
Sensitivity
Phase
100
15
Figure 7: Linearity error
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
IP = 15 A
1000
10000 100000 1000000
Frequency (Hz)
Figure 8: Frequency response
3.2
15
3.1
15
3.1
12.5
3.0
12.5
3.0
10
2.9
10
IP = 15 A
7.5
5
2.5
2.8
IP
2.7
VOUT
2.6
IP (A)
17.5
VOUT (V)
3.2
IP (A)
17.5
7.5
5
2.5
2.8
IP
2.7
VOUT
2.6
0
2.5
0
2.5
-2.5
2.4
-2.5
2.4
-0.5
0
0.5
1
1.5
2
-2
0
2
t (µs)
Figure 9: Step response
4
6
8
10
t (µs)
Figure 10: Step response
800
Primary Voltage VP (V)
10000
1000
ino (μA/Hz½)
2.9
IP = 15 A
100
10
3.6
600
3.4
400
3.2
200
0
3.0
20 kV/μs
-200
VP
VOUT
VREF
-400
1
2.8
2.6
-600
-800
0.1
1.E+1 1.E+2 1.E+3 1.E+4 1.E+5 1.E+6 1.E+7
2.4
-1
0
Frequency (Hz)
Figure 11: Input referred noise VOUT (V)
0.05
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
VOUT (V)
Linearity error (% of IPN)
0.1
Phase (°)
Typical performance characteristics CASR 15-NP
1
2
3
4
5
t (µs)
Figure 12: dv/dt
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CASR series
Typical performance characteristics CASR 25-NP
Relative Sensitivity (dB)
-0.05
-0.1
-25
0
25
Relative
Sensitivity
Phase
100
1000
10000 100000 1000000
Frequency (Hz)
IP (A)
Figure 13: Linearity error
Figure 14: Frequency response
3.2
29.2
3.2
25.0
3.1
25.0
3.1
20.8
3.0
20.8
16.7
2.9
3.0
16.7
2.8
12.5
IP
2.7
VOUT
8.3
2.6
IP
2.7
4.2
4.2
VOUT
0.0
2.5
2.6
-4.2
2.4
0.0
0
0.5
1
1.5
2.5
-4.2
2
2.4
-2
0
2
t (µs)
4
6
8
10
t (µs)
Figure 15: Step response
Figure 16: Step response
800
Primary Voltage VP (V)
10000
1000
½
2.8
8.3
-0.5
ino (μA/Hz )
2.9
IP = 25 A
IP (A)
IP (A)
IP = 25 A
12.5
VOUT (V)
29.2
100
10
3.6
600
3.4
400
3.2
200
0
3.0
20 kV/μs
-200
VP
VOUT
VREF
-400
1
2.8
2.6
-600
-800
0.1
1.E+1 1.E+2 1.E+3 1.E+4 1.E+5 1.E+6 1.E+7
Frequency (Hz)
Figure 17: Input referred noise VOUT (V)
0
VOUT (V)
Linearity error (% of IPN)
0.05
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
IP = 25 A
Phase (°)
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
0.1
2.4
-1
0
Figure 18: dv/dt
1
2
3
4
5
t (µs)
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CASR series
Typical performance characteristics CASR 50-NP
Relative Sensitivity (dB)
0
-0.05
-0.1
-50
0
Relative
Sensitivity
Phase
100
50
1000
10000 100000 1000000
Frequency (Hz)
IP (A)
Figure 19: Linearity error
Figure 20: Frequency response
3.2
58.3
3.2
50.0
3.1
50.0
3.1
41.7
3.0
41.7
3.0
2.9
33.3
25.0
16.7
8.3
2.8
2.6
8.3
2.5
0.0
2.4
-8.3
-8.3
-0.5
0
0.5
1
16.7
2.7
VOUT
0.0
1.5
IP = 50 A
25.0
IP
2
4
10000
800
Primary Voltage VP (V)
Figure 22: Step response
ino (μA/Hz½)
10
2.6
6
8
10
3.6
600
3.4
400
3.2
200
0
3.0
20 kV/μs
-200
VP
VOUT
VREF
-400
1
2.7
VOUT
t (µs)
Figure 21: Step response
100
IP
2.4
0
t (µs)
1000
2.8
2.5
-2
2
2.9
VOUT (V)
IP (A)
IP = 50 A
IP (A)
33.3
VOUT (V)
58.3
2.8
2.6
-600
-800
0.1
1.E+1 1.E+2 1.E+3 1.E+4 1.E+5 1.E+6 1.E+7
2.4
-1
0
1
2
3
4
5
t (µs)
Frequency (Hz)
Figure 23: Input referred noise VOUT (V)
Linearity error (% of IPN)
0.05
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
IP = 50 A
Phase (°)
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
0.1
Figure 24: dv/dt
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CASR series
Maximum continuous DC primary current
40
35
90
80
CASR 6-NP
25
IP (A)
IP (A)
30
20
15
10
CASR 15-NP
70
60
50
40
30
20
5
10
0
0
0
20
40
60
80
100
120
0
20
40
100
120
Figure 26: IP vs TA for CASR 15-NP
90
160
80
70
140
CASR 50-NP
120
CASR 25-NP
IP (A)
IP (A)
80
TA (°C)
TA (°C)
Figure 25: IP vs TA for CASR 6-NP
60
50
40
30
60
100
80
60
40
20
10
0
20
0
0
20
40
60
80
100
120
0
20
40
TA (°C)
60
80
100
120
TA (°C)
Figure 27: IP vs TA for CASR 25-NP
Figure 28: IP vs TA for CASR 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
AC Derating
max RMS AC current /
max DC current
1.25
1
0.75
0.5
0.25
0
10
100
1k
10k
100k
1M
f (Hz)
Figure 29: Maximum RMS AC primary current / maximum DC primary current vs frequency
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CASR series
Performance parameters definition
Ampere-turns and amperes
Sensitivity and linearity
The transducer is sensitive to the primary current linkage
QP (also called ampere-turns).
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 defined as the slope of the linear regression line for a cycle between ± IPN.
QP=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 simplified model
The static model of the transducer at temperature TA is:
VOUT = G QP + error
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 figure but
can be measured individually.
It is measured using the following primary current cycle.
IOM depends on the current value IP1.
I
In which error =
VOE + VOT (TA) + εG ·QP·G + εL(QPmax)·QPmax·G + TCG·(TA-25)·QP·G
With:
QP = NPIP
QPmax
VOUT
TA
VOE
VOT(TA)
G
εG
εL (QPmax)
:the input ampere-turns (At)
Please read above warning.
:the maxi input ampere-turns that have
been applied to the transducer (At)
:the secondary voltage (V)
:the ambient temperature (°C)
:the electrical offset voltage (V)
:the temperature variation of VO at
temperature TA (V)
:the sensitivity of the transducer (V/At)
:the sensitivity error
:the linearity error for QPmax
This model is valid for primary ampere-turns QP between
-QPmax and +QPmax only.
OM
=
V (t ) − V (t ) 1
⋅
2
Gth
OUT
1
OUT
2
IP (DC)
IP1
0A
-IP1
t
t1
Ip(3)
t2
Ip(t
3)
Figure 30:Current cycle used to measure magnetic and
electrical offset (transducer supplied)
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CASR series
Performance parameters definition (continued)
Electrical offset
Overall accuracy
The electrical offset voltage VOE can either be measured when
the ferro-magnetic parts of the transducer are:
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 eG
●● the linearity error eL (to IPN)
The magnetic offset is part of the overall accuracy. It is taken
into account in the linearity error figure provided the
transducer has not been magnetized by a current higher than
IPN.
●● completely demagnetized, which is difficult to realize,
●● or in a known magnetization state, like in the current cycle
shown in figure 30.
Using the current cycle shown in figure 30, the electrical offset
is:
V =
OE
V (t ) + V (t )
2
OUT
1
OUT
2
The temperature variation VOT of the electrical offset voltage
VOE is the variation of the electrical offset from 25°C to the
considered temperature:
V (T ) = V (T ) − V (25°C )
OT
OE
OE
Note: the transducer has to be demagnetized prior to the
application of the current cycle (for example with a
demagnetization tunnel).
Response and reaction times
The response time tr and the reaction time tra are shown in
figure 31.
Both depend on the primary current di/dt. They are measured
at nominal ampere-turns.
100 %
90 %
10 9 8
I
VOUT
Ip
tr
10 %
tra
1 2 3
Figure 31: Test connection
t
Figure 32: Response time tr and reaction time tra
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CASR series
Application information
Filtering and decoupling
Supply voltage VC
Reference VREF
The fluxgate oscillator draws current pulses of up to 30 mA at
a rate of ca. 900 kHz. Significant 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)
Ripple present on the reference output can be filtered with a
low value of capacitance because of the internal 680 Ohm
series resistance. The maximum filter capacitance value is
1 µF.Application information
10 9 8
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.
1 2 3
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]
1
0.24
Recommended
connections
IN
2
9
8
OUT
1
10
2
9
3
8
OUT
1
10
2
9
3
8
OUT
1
2
3
1.08
IN
3
10
2.16
IN
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CASR series
Application information (continued)
External reference voltage
If the Ref pin of the transducer is not used it could be either left unconnected or filtered according to the previous paragraph
“Reference VREF”.
The Ref pin has two modes Ref IN and Ref OUT:
●● In the Ref OUT mode the 2.5 V internal precision reference is used by the transducer as the reference point for bipolar
measurements; this internal reference is connected to the Ref pin of the transducer through a 680 Ohms resistor. it tolerates
sink or source currents up to ± 5 mA, but the 680 Ohms resistor prevents this current to exceed these limits.
●● In the Ref IN mode, an external reference voltage is connected to the Ref pin; this voltage is specified in the range 0 to 4 V
and is directly used by the transducer as the reference point for measurements.
The external reference voltage Vref must be able:
- either to source a typical current of
- or to sink a typical current of
Vref − 2.5
, the maximum value will be 2.2 mA typ. when Vref = 4 V.
680
2.5 − Vref
680
, the maximum value will be 3.68 mA typ. when Vref = 0 V.
50
40
30
20
10
0
-10
-20
-30
-40
-50
I P (A)
I P (A)
The following graphs show how the measuring range of each transducer version depends on the external reference voltage
value Vref.
CASR 6
0
1
2
VREF (V)
3
Upper limit : IP = -9.6 * Vref + 44.4 (Vref = 0 .. 4 V)
Lower limit : IP = -9.6 * Vref + 3.6 (Vref = 0 .. 4 V)
4
100
80
60
40
20
0
-20
-40
-60
-80
-100
CASR 15
0
1
2
VREF (V)
Upper limit : IP = -24 * Vref + 111
Upper limit : IP = 80
Lower limit : IP = -24 * Vref + 9
Lower limit : IP = -80
3
4
(Vref = 1.29 .. 4 V)
(Vref = 0 .. 1.29 V)
(Vref = 0 .. 3.7 V)
(Vref = 3.7 .. 4 V)
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CASR series
200
100
80
60
40
20
0
-20
-40
-60
-80
-100
150
100
I P (A)
I P (A)
External reference voltage (continued)
50
0
-50
-100
-150
CASR 25
0
CASR 50
-200
1
2
VREF (V)
Upper limit : IP = -40 * Vref + 185
Upper limit : IP = 85
Lower limit : IP = -40 * Vref + 15
Lower limit : IP = -85
3
4
(Vref = 2.5 .. 4 V)
(Vref = 0 .. 2.5 V)
(Vref = 0 .. 2.5 V)
(Vref = 2.5 .. 4 V)
0
1
2
VREF (V)
Upper limit : IP = -80 * Vref + 370
Upper limit : IP = 150
Lower limit : IP = -80 * Vref + 30
Lower limit : IP = -150
3
4
(Vref = 2.75 .. 4 V)
(Vref = 0 .. 2.75 V)
(Vref = 0 .. 2.25 V)
(Vref = 2.25 .. 4 V)
Example with VREF = 1.65 V:
●●
●●
●●
●●
The 6 A version has a measuring range from - 12.24 A to + 28.5 A
The 15 A version has a measuring range from - 30.6 A to + 71.4 A
The 25 A version has a measuring range from - 51 A to + 85 A
The 50 A version has a measuring range from - 102 A to + 150 A
Example with VREF = 0 V:
●●
●●
●●
●●
The 6 A version has a measuring range from + 3.6 A to + 44.4 A
The 15 A version has a measuring range from + 9 A to + 80 A
The 25 A version has a measuring range from + 15 A to + 85 A
The 50 A version has a measuring range from + 30 A to + 150 A
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CASR series
CASR 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 profile
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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CASR series
Dimensions CASR Series (in mm. General linear tolerance ± 0.25 mm)
Connection
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