Document 733 Flyback Transformers For Linear Technology LT3573 Isolated Flyback Converter • Designed for the LT3573 Isolated Flyback Converter • 1500 Vrms isolation from primary and bias to secondary; 500 Vrms isolation from primary to bias • The bias winding provides power to the chipset Core material Ferrite Terminations RoHS tin-silver over tin over nickel over phos bronze. Other terminations available at additional cost. Weight 3.9 to 4.1 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 250 per 13″ reel Plastic tape: 32 mm wide, 0.5 mm thick, 20 mm pocket spacing, 11.2 mm pocket depth PCB washing Only pure water or alcohol recommended Inductance Part at 0 A2 1 number ±10% (µH) GA3429-BL_ 24.0 GA3430-BL_ 25.0 GA3431-BL_ 25.0 Inductance at Ipk3 min (µH) 21.6 22.5 22.5 DCR max (mOhms)4 pri sec bias 95 7.5 123 90 15 95 90 5.0 70 Leakage inductance Turns ratio6 max (µH)5 pri : sec : bias 0.566 4:1:1 0.685 5:1:1 0.945 7:1:1 1. When ordering, please specify packaging code: Pri 4 2 6 5 Sec 7 8 Output7 3.3 V, 1.5 A 5.0 V, 1.0 A 3.3 V, 1.5 A Dot above pin1 GA3431-BLD Packaging: D = 13″ machine-ready reel. EIA-481 embossed plastic tape (250 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 250 kHz, 0.3 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 secondary pins shorted. 6. Turns ratio is with the secondary windings connected in parallel. 7. Output is with the secondary windings connected in parallel. Bias winding output: 3.3 V, 20 mA (GA3429 and GA3431); 5.0 V, 20 mA (GA3430). 8. Electrical specifications at 25°C. Refer to Doc 362 “Soldering Surface Mount Components” before soldering. 3 Input voltage (V) 20 – 28 10 – 14 10 – 14 Ipk3 (A) 2.1 2.1 2.1 0.450 max 11,43 0.004 /0,10 0.041 1,05 0.600 max 15,24 0.413 10,50 0.024 0,60 8 1 0.080 2,03 0.460 11,68 0.050 1,27 0.50 max 12,7 1 4 5 0.098 2,50 Dimensions are in inches mm Recommended 0.098 2,50 Land Pattern Bias 1 Secondary windings to be connected in parallel on PC board Specifications subject to change without notice. Please check our website for latest information. © Coilcraft, Inc. 2009 Document 733 Revised 04/13/09