FA2805 FA2924 FA2925 PoE Transformer for Silicon Laboratories Si3402 | Coilcraft
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SMT Flyback Transformers for
Silicon Laboratories Si3402

  • Specified by Silicon Laboratories for Si3402 PD Controller up to 15W output
  • Designed for IEEE 802.3af-compliant PoE applications
  • 36 – 72 V input. Versions for 12 V,  5 V and 3.3 V output
  • 200 kHz operating frequency
  • 1500 Vrms, one minute isolation between primary and secondary
  • Power inductor DO5010H-333 also specified for the circuit.
  • RoHS-compliant. 260°C compatible. Tin-silver over tin over nickel over phos bronze terminations.


Part number1
Click to get parts
L at 0 A2
L at Ipk3
min (µH)
DCR max (Ohms)4 Leakage
L max5
Turns ratio6
pri : sec
pri sec
FA2924-AL_ 40.0 36.0 0.100 0.025 0.666 : 0.3 2.0 3.3 V, 4.5 A
FA2805-CL_ 40.0 36.0 0.108 0.040 0.621 : 0.4 2.0 5.0 V, 3.0 A
FA2925-AL_ 40.0 36.0 0.100 0.155 0.566 : 1 2.0 12.0 V, 1.25 A
1 When ordering, please specify packaging code: e.g. FA2925-ALD
Packaging: D = 13" reel, machine-ready 
EIA-481 embossed plastic tape (175 parts per full reel).
B = Less than full reel
In tape, but not machine-ready. To have a leader and trailer added ($25 charge), use code letter D instead.
2 Inductance is for the primary, measured at 200 kHz, 0.2 Vrms, 0 Adc.
3 Ipk is peak primary current drawn at minimum input voltage.
4 DCR for the secondary is per winding measured at 25°C. For other operating temperatures, use this DCR at Temperature calculator.
5 Leakage inductance is measured across the primary with all other windings shorted.
6 Turns ratio is with the secondary windings connected in parallel.
7 Output is with the secondary windings connected in parallel.
8 Ambient temperature range: −40°C to +85°C
9 Storage temperature range: Component: −40°C to +85°C
Tape and reel packaging: −40°C to +80°C
10 Resistance to soldering heat: Three reflows at >217°C for 90 seconds (+260°C ±5°C for 20 – 40 seconds), allowing parts to cool to room temperature between.
11 Electrical specifications at 25°C.
Refer to Soldering Coilcraft Components before soldering.
PCB washing: Tested to MIL-STD-202 Method 215 plus an additional aqueous wash. More info

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Updated: July 19, 2019