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Document 385-1

Current Sense Transformers CST1, CST2AEC• Designed for up to 1 MHz and above• AEC-Q200 Grade 1 (–40°C to +125°C)• Two pinouts to meet the requirements of different applications.
• Low primary DC resistance• 500 Vrms, one minute isolation (hipot) between windings.

Q200 +125°C

Designer’s Kit C389 contains 2 each of each partCore material Ferrite
Terminations RoHS compliant tin-silver over tin over nickel over phosbronze (pins 1 – 6); RoHS compliant matte tin over nickel over copper(pins 7 – 8)
Weight 0.4 g
Ambient temperature –40°C to +125°C
Maximum part temperature 165°C (ambient + temp rise)
Storage temperature Component: –40°C to +165°C.
Tape and reel packaging: –40°C to +80°C
Resistance to soldering heat Max three 40 second reflows at+260°C, parts cooled to room temperature between cycles
Moisture Sensitivity Level (MSL) 1 (unlimited floor life at <30°C /85% relative humidity)
Packaging 250/7″reel;1000/13″ reel; Plastic tape: 16 mm wide,
0.35 mm thick, 12 mm pocket spacing, 5.6 mm pocket depth
PCB washing Tested to MIL-STD-202 Method 215 plus an additionalaqueous wash. See Doc787_PCB_Washing.pdf.

Part number1
CST1    CST2CST1-020L_ CST2-020L_
CST1-030L_ CST2-030L_
CST1-040L_ CST2-040L_
CST1-050L_ CST2-050L_
CST1-060L_ CST2-060L_
CST1-070L_ CST2-070L_
CST1-100L_ CST2-100L_
CST1-125L_ CST2-125L_

Turns		 DCR (Ohms)(N)
Inductance2Pri   Secpri : secmin (µH)
ref   max
1 : 20810.0007 0.400
1 : 301800.0007 0.870
1 : 40320
0.0007 1.14
1 : 50500
0.0007 1.50
1 : 60730
0.0007 1.98
1 : 70980
0.0007 4.75
1 : 100
2000
0.0007 5.50
1 : 1253000
0.0007 6.50

1. When ordering, please specify termination and packaging codes:
CSTX-125LC
Termination: L = RoHS compliant tin-silver over tin over nickel over phosbronze (pins 1 – 6); RoHS compliant matte tin overnickel over copper (pins 7 – 8)Special order: S = non-RoHS tin-lead (63/37) over tinover nickel over phos bronze (pins 1 – 6); non-RoHS
tin-lead over gold over nickel over copper (pins 7 – 8).
Packaging: C = 7″ machine-ready reel. EIA-481 embossed plastic
tape (250 parts per full reel). Quantities less than full
reel available: in tape (not machine ready) or withleader and trailer ($25 charge).
D = 13″ machine-ready reel. EIA-481 embossed plastic
tape. Factory order only, not stocked (1000 parts perfull reel).
B = Less than full reel. In an effort to simplify our partnumbering system, Coilcraft is eliminating the needfor multiple packaging codes. When ordering, simply
change the last letter of your part number from B to C.
2. Inductance measured between secondary pins at 100 kHz, 0.1 Vrms.
3. For specific questions regarding frequency range, please contact us at
cst@coilcraft.com.
4. Volt-time product is for the secondary, between pin 6 and 4 for CST1
and between pin 1 and 3 for CST2.
5. Primary current of 20 A causes approximately 40°C temperature risefrom 25°C ambient. Higher current causes a greater temperature rise(see Temperature Rise vs Current curve).

Frequencyrange3(kHz)46 – >1000
31 – >1000
23 – >1000
19 – >1000
15 – >1000
13 – >1000
9 – >1000
7 – >1000

Volt-time
SensedTerminatingproduct4 current Iin5 resistance RT6 Color(V-µsec)max (A)(Ohms)
dot
10.8
20
1.0
Red
16.2
20
1.5
Orange21.6
20
2.0
Yellow
27.0
20
2.5
Green
32.4
20
3.0
Blue
37.8
20
3.5
Violet
54.0
20
5.0
Gray
67.5
20
6.3
Black

6. Terminating resistance (RT) value is based on 1 Volt output with
20 Amps flowing through the primary. Varying terminating resistanceincreases or decreases output Voltage/Ampere according to the following equation: RT (Ohms) = Vout × Nsec / Iin.
7. Electrical specifications at 25°C.
Refer to Doc 362 “Soldering Surface Mount Components” before soldering.

CST18I inPri(1 turn)

6

SecI(N turns) out+

RTVout74–

8

1+CST2I inPri(1 turn)

7Specificationssales@coilcraft.com
subject to change without notice.
US +1-847-639-6400
Please check ourwebsite for latest information.
UK +44-1236-730595
sales@coilcraft-europe.com
Taiwan +886-2-2264 3646 sales@coilcraft.com.tw
China +86-21-6218 8074 sales@coilcraft.com.cn
Singapore + 65-6484 8412 sales@coilcraft.com.sg

SecI(N turns) out

3

Document 385-1

RTVout–Revised 06/08/21© Coilcraft Inc. 2021
This product may not be used in medical or highrisk applications without prior Coilcraft approval.
Specification subject to change without notice.
Please check web site for latest information.

Document 385-2

CST Series Current Sense Transformers
AEC

Q200 +125°C

Temperature rise (from 25°C)

Temperature Rise vs Current

Pinouts40

CST1

CST235873034341616252015105002468101214161878

Bottom View

Bottom View

20Current (A rms)

Dimensions

Recommended Land Pattern

Dimensions are ininches
mmUS +1-847-639-6400 sales@coilcraft.com
UK +44-1236-730595 sales@coilcraft-europe.com
Taiwan +886-2-2264 3646 sales@coilcraft.com.tw
China +86-21-6218 8074 sales@coilcraft.com.cn
Singapore + 65-6484 8412 sales@coilcraft.com.sg

Document 385-2

Revised 06/08/21© Coilcraft Inc. 2021
This product may not be used in medical or highrisk applications without prior Coilcraft approval.
Specification subject to change without notice.
Please check web site for latest information.