Document 385-1
SMT Current Sensors
–
CST Series
The CST surface mount current sensing transformers
are designed for use from 50 kHz to nearly 1 MHz to
sense continuous currents to 10 Amps and greater.
The CST1 and CST2 differ in pinout numbering and layout
in order to meet the requirements of different applications.
These transformers feature extremely low primary DC
resistance and 500 V isolation between windings. They
are available in eight different turns ratios to meet a
wide variety of requirements. They are ideal for use in
switching power supply applications.
Coilcraft Designer’sKitC389containssamplesofeach
of the standard parts shown. To order, contact Coilcraft
or visit http://order.coilcraft.com.
Sensed Terminating Volt-time
Part number1
DCR max (Ohms)
Turns (N) Inductance2
current3 resistance RT product5
Color
dot
4
CST1
CST2
pri : sec
min (µH)
Primary Secondary Iin (A)
(Ohms)
(V-µsec)
CST1-020L_
CST1-030L_
CST1-040L_
CST1-050L_
CST1-060L_
CST2-020L_
CST2-030L_
CST2-040L_
CST2-050L_
CST2-060L_
1:20
1:30
1:40
1:50
1:60
81
180
320
500
730
0.0007
0.0007
0.0007
0.0007
0.0007
0.400
0.870
1.14
1.50
1.98
10
10
10
10
10
2.0
3.0
4.0
5.0
6.0
16
24
32
41
49
Red
Orange
Yellow
Green
Blue
CST1-070L_
CST1-100L_
CST1-125L_
CST2-070L_
CST2-100L_
CST2-125L_
1:70
1:100
1:125
980
2000
3000
0.0007
0.0007
0.0007
4.75
5.50
6.50
10
10
10
7.0
10.0
12.5
57
81
101
Violet
Gray
Black
1. When ordering, please specify termination and packaging codes:
Typical Circuits
CSTX-125LC
Termination: L = RoHS compliant matte tin over nickel over phos bronze
Special order:
CST1
8
6
T = RoHS tin-silver-copper (95.5/4/0.5) or
S = non-RoHS tin-lead (63/37).
Packaging: C =7″ machine-ready reel. EIA-481 embossed plastic
Pri
(1 turn)
Sec
(N turns)
tape (250 parts per full reel).
Iin
R
T
Vout
B = Less than full reel. In tape, but not machine ready.
To have a leader and trailer added ($25 charge), use
code letter C instead.
7
4
1
D =13″ machine-ready reel. EIA-481 embossed plastic
tape (1000 parts per full reel).
2. Inductance measured between secondary pins at 100 kHz, 0.1 Vrms.
3. Primary current of 10 A causes approximately 25°C temperature rise
above 25°C ambient. Higher current causes a greater temperature
rise (see Temperature Rise vs Current curve).
CST2
8
4. Terminating resistance (R ) value is based on 1 Volt output with
T
10 Amps flowing through the primary. Varying terminating resistance
increases or decreases output Voltage/Ampere according to the
Pri
(1 turn)
Sec
(N turns)
Iin
R
T
Vout
following equation: R (Ohms) = V
× N /I
T
out
sec in.
5. Maximum volt-time product for the secondary.
6. Storage and operating temperature range -40°C to +125°C.
7. Electrical specifications at 25°C.
7
3
Specifications subject to change without notice.
Please check our website for latest information.
Document385-1 Revised06/11/09
© Coilcraft, Inc. 2009