Ferrites and accessories EFD 25/13/9 Core and accessories Series/Type: B66421, B66422 Date: June 2013 Data SheetData Sheet EPCOS AG 2013. Reproduction, publication and dissemination of this data sheet and the information contained therein without EPCOS prior express consent is prohibited.EFD 25/13/9 Core B66421 E core with flattened, lower center leg for especially flat transformer design For DC/DC converters Delivery mode: single units Magnetic characteristics (per set) 1 l/A = 0.98 mm l = 57 mm e 2 A = 58 mm e 2 A = 57 mm min 3 V = 3310 mm e Approx. weight 16.6 g/set Ungapped Material A value P Ordering code L e V nH W/set N87 2000 +30/20% 1560 < 1.8 (200 mT, 100 kHz, 100 C) B66421G0000X187 N97 2100 +30/20% 1640 < 1.5 (200 mT, 100 kHz, 100 C) B66421G0000X197 Gapped Material A value g Ordering code L e nH approx. mm N87 160 10% 125 0.55 B66421U0160K187 250 10% 195 0.30 B66421U0250K187 315 10% 246 0.22 B66421U0315K187 The A value in the table applies to a core set comprising one ungapped core (dimension g = 0) and L one gapped core (dimension g > 0). Calculation factors (for formulas, see E cores: general information ) Material Relationship between Calculation of saturation current air gap A value L K1 (25 C) K2 (25 C) K3 (25 C) K4 (25 C) K3 (100 C) K4 (100 C) N87 103 0.734 154 0.796 138 0.873 Validity range: K1, K2: 0.10 mm < s < 1.40 mm K3, K4: 50 nH < A < 410 nH L Please read Cautions and warnings and 2 06/13 Important notes at the end of this document.