56kBit Modem Transformers General The advent of high-speed 56kBit modems has necessitated the design of Line Isolation Transformers that are capable of providing extremely low distortion across a wide frequency range. OEP offers the user a number of different variants, with industry standard pin outs, from which to select a device to satisfy particular technical and commercial considerations. Construction With the exception of the SMD PC Card device, P/N PC3456 these transformers are designed for conventional PCB mounting. The epoxy resin encapsulation provides reinforced insulation to meet the requirements of EN60950 / EN41003 and BABT approvals. Double section bobbins are used except for the Z1656/4 and PC3456 versions which are concentrically wound on single section bobbins for closer coupling of the windings thus providing extremely low leakage inductance figures. Characteristics Through Hole Versions Type No. Size (mm) Return Loss (dB) 200-4kHz Insertion Loss (dB) @1kHz Frequency Response (dB) Isolation Leakage Volts Induct. 400Hz 600Hz (mH) (dB) typical (dB) typical RMS BABT Approved Number Harmonic Distortion Z1656 >20 18x18x13 encapsulated 0.80 100-4kHz +/- 0.1dB -100 -93 3750 19 CR/0125 Z1656/4 >20 18x18x13 encapsulated 0.80 100-4kHz +/- 0.1dB -88 -91 3750 2.8 CR/0126 Z1612E 18x18x13 >20 encapsulated 1.50 200-4kHz +/- 0.1dB -83 -93 3750 19.4 CR/0128 Z1256 19x15x11.2 >26 encapsulated 1.25 50-5kHz +/- 0.07dB -84 -93 3750 14.4 CR/0127 PC Card (SMD) Version PC3456 >31 23x16x4.5 including pins 4.00 100-5kHz +/- 0.05dB -97 -104 1500 1.3 Pending OXFORD ELECTRICAL PRODUCTS 15-17 Industrial Estate, Wroslyn Road, Freeland, Witney, Oxfordshire, OX8 8HZ England Tel: +44 (0) 1993 883214 Fax: +44 (0) 1993 882500 2/96