© Coilcraft, Inc. 2009
Specifications subject to change without notice.
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Flyback Transformers
Document 458
Document 458
Revised 10/29/08
For National Semiconductor
LM5070 PoE Interface – 7 Watt
Inductance
Inductance
Leakage
Part
at 0 A2
at Ipk3
DCR max (Ohms)4
inductance
Turns ratio6
Ipk3
number1
±10% (µH)
min (µH)
pri
bias
sec
max (µH)5
pri : sec
pri : bias
(A)
Output7
C1587-AL_
155
139.5
0.414
0.822
0.036
4.00
1 : 0.19
1 : 0.667
0.65 3.3 V, 2.12 A
C1588-AL_
155
139.5
0.414
0.822
0.060
3.60
1 : 0.262
1 : 0.667
0.65
5.0 V, 1.4 A
C1589-AL_
155
139.5
0.414
0.822
0.343
3.25
1 : 0.667
1 : 0.667
0.65
12 V, 0.6 A
1. When ordering, please specify packaging code:
C1589-AL
D
Packaging: D =13
″ machine-ready reel. EIA-481 embossed plastic
tape (200 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 10 kHz, 0.1 Vrms, 0 Adc.
3.
Ipk is peak primary current drawn at minimum input voltage.
4. DCR for the secondary is per winding.
5. 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.
0.080
2,03
1
0.433
11,00
0.50
12,7
0.041
1,05
0.413
10,50
0.600
15,24
max
0.460
11,68
0.024
0,60
0.050
1,27
0.098
2,50
0.098
2,50
max
max
4
5
1
8
Recommended
Land Pattern
Dot above pin1
0.004 /0,10
Core material Ferrite
Terminations RoHS tin-silver over tin over nickel over phos
bronze. Other terminations available at additional cost.
Weight 3.85 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 200 per 13
″ reel Plastic tape: 32 mm wide, 0.5 mm
thick, 24 mm pocket spacing, 11.2 mm pocket depth
PCB washing Only pure water or alcohol recommended
• Flyback transformers for 7 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
4
1
3
2
8
6
5
Bias
Pri
Sec
7
Secondary windings to be connected
in parallel on the PC board
Dimensions are in
inches
mm
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