Document 1591-1

Ethernet Isolation Transformers
HalogenFree• Complies with IEEE 802.3 Standards• Chip-style in a compact SMT package: 4.7 x 3.1 x 3.1 mm• Fully automated for cost reduction and reliability• AEC-Q200 qualified

AEC

Core material Ferrite
Terminations RoHS compliant matte tin over nickel over silver-platinum-

Q200 +125°C

glass frit

Weight 120 – 130 mg
Ambient temperature –40°C to +125°C with Irms current
Max part temperature +140°C(ambient + temp rise)
Storage temperature Component: –40°C to +125°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 600/7″ reel; 2200/13″ reel Plastic tape: 12 mm wide,
0.25 mm thick, 8 mm pocket spacing, 3.25 mm pocket depth
PCB washing Tested to MIL-STD-202 Method 215 plus an additionalaqueous wash. See Doc787_PCBt_Washing.pdf.

PartInductance2
number1min (µH)
1812TRX-S124R_120
1812TRX-S254R_250Imp. ratio
pri : sec
1CT : 1CT
1CT : 1CT

DCR max(Ohms)
2.5
3.8

Isolation3(Vrms)
1500
1500

Insertion lossmax (dB)
0.15
0.35

Bandwidth(MHz)0.1 – 1100
0.1 – 820

IDC4max (mA)
430
350

1. When ordering, please specify packaging code:
1812TRX-S254RC
C = 7″ machine-ready reel. EIA-481 embossed plastic
tape (600 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 (2200 parts perfull reel).
2. Inductance is per winding, measured at 100 kHz, 0.1 Vrms, 0 Adc using
an Agilent/HP 4263B LCR meter and a Coilcraft CCF 1113 fixture.
3. 1500 Vrms, one minute isolation (hipot) between primary to secondary.
4. IDC max per the center tap is the current required to increase the parttemperature 15°C from ambient 25°C.
5. Electrical specifications at 25°C. Measurements are referenced to50 Ohms.
Refer to Doc 362 “Soldering Surface Mount Components” before soldering.
Packaging:US +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 1591-1

Revised 09/13/24© Coilcraft Inc. 2024
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 1591-2

Ethernet Isolation Transformers – 1812TRX
Return Loss0HalogenFree50.122
max3,10+150.130max
3,310.185 max
4,70

20
25
300.016 typ
0,40

35

0.071
1,80



0.071
1,80

1-S124-S254

45
50

0.1

10.022 typ
0,55

10100

Frequency (MHz)

S x2

L x6
M x2

0.0280,700.035 typ
0,90

1000

Insertion Loss

0.052
1,325

0.028
0,70

40

T x2

4

350

Attenuation (dB)

AEC
Q200 125°C

Attenuation (dB)

100.5

2

1.0

1
P

1.5

N x4

R x2
6
P

Recommended
Land Pattern

2.0

Dimensions are ininches
mm2.5

L
0.039
1,03.03.5M
0.028
0,70N
0.022
0,55P
0.071
1,80R
0.052
1,325ST
0.028 0.028
0,70 0,70inches
mm

4.0-S124-S254

4.5
5.00.11101001000

Frequency (MHz)US +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 1591-2

Revised 09/13/24© Coilcraft Inc. 2024
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.