Document 423
PoE Transformer
For National Semiconductor
LM5070 PoE Interface
This surface mount flyback transformer was developed
specifically for the National Semiconductor LM5070
Powered Devices Interface in 13 Watt Power over
Ethernet (PoE) applications.
It is designed to operate at frequencies up to 1 MHz
with an with an input voltage of 36 – 72 Volts. Output
with the secondary windings connected in parallel is
3.3 V, 4.5 A. Isolation is 1500 Vrms from the primary
and auxiliary windings to the secondary.
Coilcraft can design custom transformers with volt-
age, inductance and DCR values to meet your specific
requirements.
For free evaluation samples, contact Coilcraft or order
them on-line at
www.coilcraft.com.
DCR max (Ohms)
4
Part
L at 0 A
2
L at
Ipk
3
number
1
±10% (µH) ±10% (µH) pri
aux
sec
C1023-AL_
110
99.0
0.139 0.656 0.016
1. When ordering, please specify a
packaging
code:
C1023-ALD
Packaging: D
= 13″ machine ready reel. EIA-481 embossed plastic
tape (175 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 10 kHz, 0.1 Vrms, 0 Adc.
Leakage
L (µH)
5
1.40
Turns ratio
6
pri : sec pri : aux
1
:
0.19 1
:
0.69
Capacitance
7
Ipk
3
Isolation
8
(pF)
(A)
(Vrms)
70
1.5
1500
3.
Ipk
is the peak current drawn at minimum input voltage.
4. DCR for the secondary is per winding.
5. Leakage inductance is for the primary winding with all other pins
shorted.
6. Turns ratio is with the secondary windings connected in parallel.
7. Capacitance measured between pins 3 and 4 with other pins shorted.
8. Isolation is measured from the primary and aux to the secondary.
9. Operating temperature range –40°C to +85°C.
10. Electrical specifications at 25°C.
12
11
10
Dot indicates pin 1
1
12
0.028
0,711
0.130
3,30
1
0.930
23,62
0.050
1,27
4
Pri
C1023-AL
Sec
9
8
7
0.810
max
20,57
6
Recommended
Land Pattern
7
6
1
1.181 max
30,00
0.118
3,0
0.118
3,0
Aux
3
Secondary windings to be connected
in parallel on PC board.
0.450
max
11,43
0.827
21,00
0.969
24,60
0.004 /0,10
Weight:
Terminations:
Tape and reel:
0.080
2,03
12.4 g
Tin-silver over tin over nickel over phos bronze
175/13″ reel, 44 mm tape width
Specifications subject to change without notice.
Please check our website for latest information.
Document 423
Revised 10/25/06
© Coilcraft, Inc. 2008
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