Coilcraft Flyback Transformers
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Flyback Transformers for
12 Volt Nominal Input

  • Developed for applications with 10 – 14 V input
  • 1500 Vrms isolation from primary and bias to secondary;
    500 Vrms isolation from primary to bias, tested for one minute.
  • Bias winding provides power to the chipset
  • RoHS-compliant. 260°C compatible. Tin-silver (96.5/3.5) over tin over nickel over phos bronze terminations


Part number1
Click to get parts
at 0A2
±10% (µH)
at Ipk3
min (µH)
max (µH)
Turns ratio Ipk3
GA3430-BL_ 25.0 22.5 90 (pri)
15 (sec)
95 (bias)
0.685 5 : 1 : 1 2.1 10 – 14 5.0 V, 1.0 A
GA3431-BL_ 25.0 22.5 90 (pri)
5 (sec)
70 (bias)
0.945 7 : 1 : 1 2.1 10 – 14 3.3 V, 1.5 A
1 When ordering, please specify termination and packaging codes: e.g. GA3431-BLD
  Termination: L = RoHS compliant tin-silver over tin over nickel over phos bronze
Special order, added cost: T = RoHS tin-silver-copper (95.5/4/0.5) or
= non-RoHS tin-lead (63/37).
  Packaging: D = 13" reel, machine-ready 
EIA-481 embossed plastic tape (250 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 250 kHz, 0.3 Vrms, 0 Adc using an Agilent/HP 4263B impedance analyzer or equivalent.
3 Ipk: Peak primary current drawn at minimum input voltage.
4 DCR for the secondary is per winding. DCR measured at 25°C. For other operating temperatures, use this DCR at Temperature calculator.
5 Leakage inductance is for the primary winding with the secondary windings shorted.
6 Output is with the secondary windings connected in parallel.
Bias winding output:  5.0 V, 20 mA (GA3430); 3.3 V, 20 mA (GA3431).
7 Ambient temperature range: −40°C to +85°C
8 Storage temperature range: Component: −40°C to +85°C
Tape and reel packaging: −40°C to +80°C
9 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: April 16, 2018