AN3212 Datasheet, PDF (34/36 Pages) STMicroelectronics – The driving idea behind this application note is to exploit the possibility

7 W transformer specifications
AN3212
7.2
Electrical specifications
1. BOBBIN: EE16 (4 +4 pin)
2. CORE: EE16 AL:1140 +/-25%nH/N*N (TDK PC40 MATERIAL or equivalent)
3. Primary inductance (P1 - P2): 1.5 mH +/- 10% (at 100 kHz, 1 V)
4. Leakage inductance (P1 - P2): < 50 µH (at 100 kHz, 1 V) with other pins shorted
Figure 59. Transformer electrical drawing
Winding
N1
N2
N3
N4
N5
N6
Pins
P2----A
P4
FLY1
----
FLY2
P4
A----P1
P3----P4
!-V
Table 4. Transformer winding data
Wire type
Wire size
# turns
2UEW
Copper foil
Φ 0.15 mm * 2
54T 2Layer
0.025 mmT * 7 mmW
Triple insulation winding wire
Totoku TIW-3 UL FILE no. E66483
Φ 0.55 mm
10T
or equivalent
Copper foil
0.025 mmT * 7 mmW
2UEW
2UEW
Φ 0.15 mm * 2
Φ 0.22 mm
54T 2Layer
14T
Note: 1 HIPOT: 3 KV_AC primary to secondary 1 min. 10 mA
2 Start winding from the pin marked “·” (especially for N5 and point A)
3 Cut off pin 5, 6, 7, 8
4 Attach a copper foil 3M #1245 tape (4 mm width*10 mm length) to the Core,
5 Make sure the foil maintains good contact with the ferrite core, and solder a UL xpvc wire to
pin 4 as short as possible.
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