Document 729
For Microsemi
Flyback Transformer PoE PD Power Supply
• Developed for use with Microsemi UC3844 Current Mode
Controller and LX1752 Buck Regulator
• 1500 Vrms isolation from primary, auxiliary and reset to
secondary; 500 Vrms from primary and reset to auxiliary
• Designed for 36 V – 57 V input; 200 kHz
Core material Ferrite
Terminations RoHS tin-silver over tin over nickel over phos
bronze. Other terminations available at additional cost.
Weight 6.7 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)
Mean Time Between Failures (MTBF) 26,315,789 hours
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
Part
L at 0 A2
±10% (µH)
L at Ipk3
min (µH)
Input
voltage (V)
DCRmax
(Ohms)
LeakageL4
max (µH)
Turns
ratios
Ipk3
(A)
number1
Outputs5
HA3905-CL_
27.0
24.3
37 –57
0.170 (pri)
1.9
3.75:1 (pri:sec )
1.36:1 (pri:aux)
1:1 (pri:reset)
1.2
5 V, 2.5 A (sec)
12 V, 20 mA (aux)
0.015 (sec)
0.385(aux)
0.371 (reset)
1. When ordering, please specify packaging code:
HA3905-CLD
2. Inductance is for the primary, measured at 250 kHz, 0.1 Vrms, 0 Adc.
3. Ipk is peak primary current drawn at minimum input voltage.
4. Leakage inductance measured on the primary winding with all
secondary pins shorted.
5. Output of the seconday is with the windings connected in parallel.
6. Electrical specifications at 25°C.
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.
Refer to Doc 362 “Soldering Surface Mount Components” before soldering.
Dot above pin1
5
10
9
Pri
Sec
0.500
12,70
max
3
6
7
Reset
4
0.004/0,10
0.039
1,00
1
0.699
17,75
max
Aux
0.050
1,27
0.028
0,70
0.512
13,00
2
0.080
2,03
0.590
14,99
6
Secondary windings to be connected
in parallel on the PC board
5
1
0.530
13,46
Recommended
Land Pattern
max
1
0.098
2,50
0.098
2,50
10
inches
mm
Dimensions are in
These parts are preproduction products for electrical evaluation only.
Specification subject to change without notice.
Document729 Revised08/13/09
© Coilcraft, Inc. 2009