Document 729 Flyback Transformer For Microsemi 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 number1 HA3905-CL_ L at Ipk3 min (µH) 24.3 L at 0 A2 ±10% (µH) 27.0 Input voltage (V) 37 –57 DCR max (Ohms) 0.170 (pri) 0.015 (sec) 0.385 (aux) 0.371 (reset) 1. When ordering, please specify packaging code: HA3905-CLD 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. Leakage L4 Turns max (µH) ratios 1.9 3.75 : 1 (pri : sec ) 1.36 : 1 (pri : aux) 1 : 1 (pri : reset) Ipk3 (A) 1.2 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. Refer to Doc 362 “Soldering Surface Mount Components” before soldering. 5 Dot above pin1 10 9 Pri Sec 0.500 max 12,70 3 Reset 4 0.004 /0,10 0.039 1,00 Aux 0.028 0,70 0.512 13,00 6 5 0.080 2,03 0.590 14,99 0.050 1,27 2 Secondary windings to be connected in parallel on the PC board 1 Recommended Land Pattern 0.530 max 13,46 1 10 0.098 2,50 0.098 2,50 inches mm These parts are preproduction products for electrical evaluation only. Specification subject to change without notice. © Coilcraft, Inc. 2009 6 7 1 0.699 max 17,75 Dimensions are in Outputs5 5 V, 2.5 A (sec) 12 V, 20 mA (aux) Document 729 Revised 08/13/09