Ferrites and accessories EFD 25/13/9 Core and accessories Series/Type: B66421, B66422 Date: June 2013 Data SheetData Sheet EPCOS AG 2015. Reproduction, publication and dissemination of this publication, enclosures hereto and the information contained therein without EPCOS prior express consent is prohibited. EPCOS AG is a TDK Group Company. 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.