772 Series www.murata-ps.com Pulse Transformers SELECTION GUIDE Primary Inductance (Min.) 1.0 1.0 1.0 1.0 4.0 4.0 4.0 RoHS compliant Primary Et Constant (Min.) 120 120 120 120 240 240 Inductance to 16.3mH Leakage Inductance (Max.) 2.0 3.0 3.5 3.5 5.0 Interwinding Capacitance (Max.) 50 40 30 30 0.25 0.25 0.24 0.23 0.22 - 0.28 PCB mounting UL 94 V-0 package materials Up to 4000Vrms isolation Backward compatible with Sn/Pb soldering systems DC Resistance (Max.) Primary winding DC Resistance (Max.) Secondary1 winding DC Resistance (Max.) Secondary2 winding Isolation voltage (flash tested for 1 second) DESCRIPTION The 772 series of pulse transformers are intended for medium power applications in switch mode power supplies and thyristor/triac firing (e.g. motor control applications). The standard turns ratios may be modified on any transformer with three windings by connecting any two windings in series. 2.5 77209C 77208C Units 1:1 1:1:1 2:1:1 4.0 16.3 16.3 16.3 mH 240 240 482 482 482 Vμs 11 11 11 18 40 40 μH 55 35 18 35 65 40 40 pF 0.24 0.86 0.90 0.90 0.84 3.50 3.60 3.50 0.12 0.12 0.83 0.76 0.76 0.38 3.40 3.10 1.60 0.15 0.15 - 1.10 1.10 0.50 - 4.20 2.00 4.0 1:1:1 1:1:1 2:1:1 77207C 77206C 77205SC 1:1 Up to 482 Vμs Et rating 1:1 77205C Turns ratio FEATURES ATURES 1:1:1 2:1:1 2:1:1 77204C 77203HVC 77203C 77202C Parameter 77201C Order Code 2.5 Ω kVrms ABSOLUTE MAXIMUM RATINGS Operating free air temperature range 0°C to 70°C Storage temperature range -60°C to 125°C Lead Temperature 1.5mm from case for 10 seconds 300°C SOLDERING INFORMATION1 Peak wave solder temperature 300˚C for 10 seconds Pin finish Matte tin with nickel pre-plate Specifications typical at TA = 25°C 1 For further information, please visit www.murata-ps.com/rohs For full details go to www.murata-ps.com/rohs www.murata-ps.com/support KMP_772C_B04 Page 1 of 3 772 Series Pulse Transformers PACKAGE SPECIFICATIONS MECHANICAL DIMENSIONS RECOMMENDED FOOTPRINT DETAILS 25.40 (1.00) 1 Ø1.20+0.15-0.00 (Ø0.472+0.006-0.000) 3 77202C YYWW 2 5 20.30 (0.799) 4 2.54 (0.1) 6 2.54 (0.1) 5.92 (0.233) 12.30 (0.484) Unless otherwise stated all dimensions in mm (inches) ± 0.25 (0.01). TUBE DIMENSIONS 0.66 (0.026) Max. 2.53 (0.100) 22.50 (0.886) 13.30 (0.524) 12.5 (0.492) 5.08 (0.2) 0.75±0.12 (0.030±0.005) 15.24 (0.6) 5.08 (0.2) 3.05 (0.120) 20.32 (0.8) 11.50 (0.453) All dimensions in mm (inches) XX.X±0.50(0.02), XX.XX±0.25(0.01). All pins on a 2.54 (0.1) pitch. Tube length: 530 (20.87) Max. Unless otherwise stated all dimensions in mm (inches) ± 0.25 (0.01). PIN CONNECTION STYLE - 8 PIN DIP (TOP VIEW) Screen* 1 3 Secondary 1 4 Primary 5 Secondary 2 2 6 * Only on 77205SC www.murata-ps.com/support KMP_772C_B04 Page 2 of 3 772 Series Pulse Transformers TECHNICAL NOTES ISOLATION VOLTAGE REPEATED HIGH-VOLTAGE ISOLATION TESTING ‘Hi Pot Test’, ‘Flash Tested’, ‘Withstand Voltage’, ‘Proof Voltage’, ‘Dielectric Withstand Voltage’ & ‘Isolation Test Voltage’ are all terms that relate to the same thing, a test voltage, applied for a specified time, across a component designed to provide electrical isolation, to verify the integrity of that isolation. It is well known that repeated high-voltage isolation testing of a barrier component can actually degrade isolation capability, to a lesser or greater degree depending on materials, construction and environment. This series has toroidal isolation transformers, with no additional insulation between primary and secondary windings of enameled wire. While parts can be expected to withstand several times the stated test voltage, the isolation capability does depend on the wire insulation. Any material, including this enamel (typically polyurethane) is susceptible to eventual chemical degradation when subject to very high applied voltages thus implying that the number of tests should be strictly limited. We therefore strongly advise against repeated high voltage isolation testing, but if it is absolutely required, that the voltage be reduced by 20% from specified test voltage. All products in this series are 100% production tested at their stated isolation voltage. A question commonly asked is, “What is the continuous voltage that can be applied across the part in normal operation?” For a part holding no specific agency approvals both input and output should normally be maintained within SELV limits i.e. less than 42.4V peak, or 60VDC. The isolation test voltage represents a measure of immunity to transient voltages and the part should never be used as an element of a safety isolation system. The part could be expected to function correctly with several hundred volts offset applied continuously across the isolation barrier; but then the circuitry on both sides of the barrier must be regarded as operating at an unsafe voltage and further isolation/insulation systems must form a barrier between these circuits and any user-accessible circuitry according to safety standard requirements. Murata Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. ISO 9001 and 14001 REGISTERED This consideration equally applies to agency recognized parts rated for better than functional isolation where the wire enamel insulation is always supplemented by a further insulation system of physical spacing or barriers. Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. © 2011 Murata Power Solutions, Inc. www.murata-ps.com/support KMP_772C_B04 Page 3 of 3