Document 445
Flyback Transformers
For National Semiconductor
LM5070 PoE Interface – 13 Watt
• Flyback transformers for 13 W PoE applications
• Designed to operate in continuous mode at 250 kHz with
an input of 36 – 72 Vdc
• 1500 Vrms isolation from primary and bias to secondary
Core material
Ferrite
Terminations
RoHS tin-silver over tin over nickel over phos
bronze. Other terminations available at additional cost.
Weight
6.15 g
Ambient temperature
–40°C to +85°C
Storage temperature
Component: –40°C to +85°C.
Packaging: –40°C to +80°C
Resistance to soldering heat
Max three 40 second reflows at
+260°C, parts cooled to room temperature between cycles
Moisture Sensitivity Level (MSL)
1 (unlimited floor life at <30°C /
85% relative humidity)
Failures in Time (FIT) / Mean Time Between Failures (MTBF)
38 per billion hours / 26,315,789 hours, calculated per Telcordia SR-332
Packaging
175 per 13″ reel Plastic tape: 32 mm wide, 0.5 mm
thick, 28 mm pocket spacing, 12.93 mm pocket depth
PCB washing
Only pure water or alcohol recommended
Inductance
Part
at 0 A
2
1
number
±10% (µH)
C1495-AL_
127
C1585-AL_
127
C1586-AL_
127
Inductance
at
Ipk
3
min (µH)
114.3
114.3
114.3
DCR max (Ohms)
4
pri
bias
sec
0.255
0.310 0.024
0.222
0.348 0.039
0.199
0.308 0.129
2.
3.
4.
5.
Leakage
inductance
max (µH)
5
1.25
0.950
0.650
Turns ratio
6
pri : sec pri : bias
1
:
0.166
1
:
0.50
1
:
0.25
1
:
0.50
1
:
0.50
1
:
0.50
Ipk
3
(A)
1.0
1.0
1.0
Output
7
3.3 V, 4.0 A
5.0 V, 2.6 A
12 V, 1.08 A
1. When ordering, please specify
packaging
code:
C1586-ALD
Packaging: D
= 13″ machine-ready reel. 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.
Dot above pin1
Inductance is for the primary, measured at 250 kHz, 0.2 Vrms, 0 Adc.
Ipk
is peak primary current drawn at minimum input voltage.
DCR for the secondary is per winding.
Leakage inductance measured between pins 3 and 4 with all other pins
shorted.
6. Turns ratio is with the secondary windings connected in parallel.
7. Output of the secondary is with the windings connected in parallel. Bias
winding output is 12 V, 20 mA.
8. Electrical specifications at 25°C.
Refer to Doc 362 “Soldering Surface Mount Components” before soldering.
0.500 max
12,70
0.039
1,00
0.004 /0,10
0.699 max
17,75
0.512
13,00
1
3
Pri
0.028
0,70
10
8
7
Sec
9
10
0.080
2,03
0.590
14,99
0.050
1,27
4
2
Bias
0.530 max
13,46
5
6
Recommended
Land Pattern
0.098
2,50
1
1
0.098
2,50
Secondary windings to be connected
in parallel on the PC board
Specifications subject to change without notice.
Please check our website for latest information.
Document 445
Revised 10/29/08
© Coilcraft, Inc. 2009
Embedded System
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