Data Sheet

© 2009 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN7621 • Rev. 1.0.3 14
FAN7621 — PFM Controller for Half-Bridge Resonant Converters
Typical Application Circuit (Continued)
Usually, LLC resonant converters require large leakage inductance value. To obtain a large leakage inductance,
sectional winding method is used.
 Core: EC35 (Ae=106 mm
2
)
 Bobbin: EC35 (Horizontal)
 Transformer Model Number: SNX-2468-1
EC35
N
p
2
6
9
12
10
N
s2
13
N
s1
Figure 30. Transformer Construction
Pins (S → F) Wire Turns Note
N
p
6 → 2 0.08φ×88 (Litz Wire) 36
N
s1
12 → 9 0.08φ×234 (Litz Wire) 4 Bifilar Winding
N
s2
10 → 13 0.08φ×234 (Litz Wire) 4 Bifilar Winding
Pins Specifications Remark
Primary-Side Inductance (L
p
) 2－6
550
μH ± 10%
100kHz, 1V
Primary-Side Effective Leakage (L
r
) 2－6
110
μH ± 10%
Short one of the secondary windings
For more detailed information regarding the transformer, visit http://www.santronics-usa.com/documents.html
or
contact [e-mail]
or [phone] (Sunnyvale, California USA).