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© Coilcraft Inc. 2013
This product may not be used in medical or high
risk applications without prior Coilcraft appr
oval.
Specification subject to change without notice.
Please check web site for latest infor
mation.
Flyback Transformers
Document 458
Document 458 Revised 04/01/13
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-ALD
Packaging: D = 13″ machine-ready reel. EIA-481 embossed plastic
tape.
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
45
18
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.
Tape and reel 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
PCB washing Tested with pure water or alcohol only. For other solvents,
see Doc787_PCB_Washing.pdf
• 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
28
6
5
Bias
Pri Sec
7
Secondary windings to be connected
in parallel on the PC board
Dimensions are in inches
mm
Packaging:
C1587-AL 250 per 13″ reel Plastic tape: 32 mm wide,
0.5 mm thick, 20 mm pocket spacing, 11.2 mm pocket depth
C1588 / C1589-AL 200 per 13″ reel Plastic tape: 32 mm wide,
0.5 mm thick, 24 mm pocket spacing, 11.2 mm pocket depth
