Document 736 Flyback Transformer For Linear Technology LT3751 Capacitor Charger Controller • Flyback transformer for the Linear Technology LT3751 Capacitor Charger Controller • 5 – 24 V input; 5 V, 3.6 A and ±15 V, 1.2A outputs • 1500 Vrms isolation from primary to secondary windings Core material Ferrite Terminations RoHS tin-silver over tin over nickel over phos bronze. Other terminations available at additional cost. Weight 25.0 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 24 per tray PCB washing Only pure water or alcohol recommended Part number HA3994-AL 1. 2. 3. 4. Inductance at 0 A1 ±10% (µH) 7.50 Inductance DCR max (Ohms)3 at Ipk2 min (µH) pri sec 1 sec 2 sec 3 6.75 0.018 0.020 0.031 0.031 Inductance is measured at 100 kHz, 0.1 Vrms. Peak primary current drawn at minimum input voltage. DCR for the primary is with the windings connected in parallel. Leakage inductance is for both windings of the primary with the secondary windings shorted. Leakage inductance4 Turns ratio5 max (µH) pri : sec 1 : sec 2 : sec 3 0.22 1 : 0.5 : 1.5 : 1.5 Volt-time Ipk2 product (A) typ (V µsec) 5.0 37.5 5. Turns ratios are with the primary windings connected in parallel. 6. Electrical specifications at 25°C. Refer to Doc 362 “Soldering Surface Mount Components” before soldering. Dot indicates pin 1 0.108 2,75 1 12 HA3994-AL CCIxxxx 0.039 1,00 0.148 3,75 1.053 max 26,75 0.148 3,75 1.10 28,2 1 1 2 12 Recommended Land Pattern Pri 5 – 24 V 11 12 4 Sec 1 5 V, 3.6 A 9 5 Sec 2 15 V, 1.2 A 0.079 2,00 8 6 Sec 3 –15 V, 1.2 A 7 Primary windings to be connected in parallel on PC board. 0.551 max 14,0 1.024 26,0 1.35 max 34,29 0.004 / 0,10 Dimensions are in inches mm Specifications subject to change without notice. Please check our website for latest information. © Coilcraft, Inc. 2009 Document 736 Revised 01/16/09