78250 Series www.murata-ps.com MAX250/MAX251 Compatible Converter Transformers CHARACTERISTICS 78250C/78250MC Parameter Conditions Min. Typ. Max. Units Primary Inductance, L 10kHz, 100mV 1.0 2.0 2.5 mH P Leakage Inductance, L 100kHz, 100mV 2.0 3.0 H L Interwinding Capacitance, C 100kHz, 100mV 69 90 pF WW Primary D.C. Resistance, R <0.1VDC 1.0 2.0 DC Volt-time Product, Et Pins1/2 or 2/3 50 Vs FEATURES CHARACTERISTICS 78250VC/78250MVC Parameter Conditions Min. Typ. Max. Units n RoHS compliant Primary Inductance, L 10kHz, 100mV 1.0 2.0 2.5 mH P n Maxim MAX250/MAX251 compatible Leakage Inductance, L 100kHz, 100mV 35 40 H L Interwinding Capacitance, C 100kHz, 100mV 9 12 pF n Isolation to 4kVrms WW Primary D.C. Resistance, R <0.1VDC 1.4 1.8 DC n Industry-standard pinout Volt-time Product, Et Pins1/2 or 2/3 50 Vs n Surface mount option ORDER CODE DETAILS n UL 94 V-0 package materials Order Code Package Type Packaging Type Quantity n Low profile 78250C / 78250VC 6 Pin DIL Tube 50 78250MC / 78250MVC 6 Pin SM Tube 50 n Toroidal construction 78250MC-R / 78250MVC-R 6 Pin SM Tape & Reel 500 n Fully encapsulated ABSOLUTE MAXIMUM RATINGS n Industrial temperature range Operating free air temperature range -40C to 85C Storage temperature range -50C to 125C DESCRIPTION Lead temperature 1.5mm from case for 10 seconds 300C Peak current, I 300mA The 78250 series of converter transformers PK Isolation voltage 78250(M)C (flash tested for 1 second) 1.5kVrms are specifically designed for use with Maxim 4.0kVrms Isolation voltage 78250(M)VC (flash tested for 1 second) chipsets to provide isolated RS232 interfaces. Carefully controlled turns ratios ensure consistent All specifications typical at T =25C A performance whilst a toroidal construction TECHNICAL NOTES minimises EMI. ISOLATION VOLTAGE REPEATED HIGH-VOLTAGE ISOLATION TESTING Hi Pot Test, Flash Tested, Withstand Voltage, Proof Volt- It is well known that repeated high-voltage isolation Surface-mount parts age, Dielectric Withstand Voltage & Isolation Test Voltage testing of a barrier component can actually degrade are all terms that relate to the same thing, a test voltage, isolation capability, to a lesser or greater degree The surface-mount (M suffix) products are not applied for a specified time, across a component designed depending on materials, construction and environ- recommended for new designs. For existing designs, to provide electrical isolation, to verify the integrity of that ment. This series has toroidal isolation transformers, however, Murata Power Solutions will continue to isolation. with no additional insulation between primary and manufacture and fully support these parts. secondary windings of enameled wire. While parts All products in this series are 100% production tested at For recommended alternatives please refer to the can be expected to withstand several times the their stated isolation voltage. stated test voltage, the isolation capability does de- 78250J Series datasheet. A question commonly asked is, What is the continuous pend on the wire insulation. Any material, including voltage that can be applied across the part in normal opera- this enamel (typically polyurethane) is susceptible tion to eventual chemical degradation when subject to For a part holding no specific agency approvals both input very high applied voltages thus implying that the and output should normally be maintained within SELV limits number of tests should be strictly limited. We there- i.e. less than 42.4V peak, or 60VDC. The isolation test volt- fore strongly advise against repeated high voltage age represents a measure of immunity to transient voltages isolation testing, but if it is absolutely required, that and the part should never be used as an element of a safety the voltage be reduced by 20% from specified test isolation system. The part could be expected to function cor- voltage. rectly with several hundred volts offset applied continuously This consideration equally applies to agency recog- across the isolation barrier but then the circuitry on both nized parts rated for better than functional isolation sides of the barrier must be regarded as operating at an where the wire enamel insulation is always supple- unsafe voltage and further isolation/insulation systems must mented by a further insulation system of physical For full details go to form a barrier between these circuits and any user-acces- For full details go towww.cd4power.com/rohs spacing or barriers. www.murata-ps.com/rohs sible circuitry according to safety standard requirements. www.murata-ps.com/support KMP 78250C C07 Page 1 of 378250 Series MAX250/MAX251 Compatible Converter Transformers PACKAGE SPECIFICATIONS MECHANICAL DIMENSIONS 0.5 6 Pin DIL 6 Pin SM (12.70) 0.375 0.375 (9.52) MAX (9.52) Max. Primary Secondary Primary Secondary 1 6 1 6 0.354 0.354 2 2 5* (9.0) Max. (9.0) Max. 78250MC 78250C 3 4 3 4 XYYWW XYYWW 0.25 0.25 (6.35) (6.35) 0.1350.02 0.0120.30 0.025 (0.63) (3.440.50) (0.0080.20) 0.035 (0.90) 0.021 (0.53) 0.1 (2.54) 0.025 (0.63) 0.012(0.30) 0.021 (0.53) 0.008(0.20) 0.40 0.1 (10.16) (2.54) Unless otherwise stated all dimensions in inches (mm) 0.01 (0.25). All pins on a 0.1 (2.54) pitch and within 0.01 (0.25) of true position. * Pin 5 is connected to secondary center tap. Package Weight 1.0g TYP. RECOMMENDED FOOTPRINT DETAILS 6 Pin DIL 6 Pin SM 0.10 (2.54) 0.10 (2.54) 0.06 (1.60) 0.06 (1.60) 0.10 (2.54) 0.10 (2.54) 0.10 (2.54) 0.10 (2.54) +0.006 (0.15)+0.006 (0.15) 0.05 (1.20) 0.05 (1.20) -0.000 (0.00)-0.000 (0.00) 0.04 0.04 (1.00) (1.00) 0.45 0.45 (11.50) (11.50) Unless otherwise stated all dimensions in inches (mm) 0.01 (0.25). All pins on a 0.1 (2.54) pitch and within 0.01 (0.25) of true position. 1 TUBE OUTLINE DIMENSIONS SOLDERING INFORMATION 0.43 Pin finish Matte tin (10.95) Peak wave solder temperature 300C for 10 seconds Unless otherwise stated all 0.16 (4.00) 2 dimensions in inches (mm) Peak reflow temperature 220C 0.01 (0.25). 1 For further information, please visit www.murata-ps.com/rohs 0.0230.005 0.51 Tube length: 18.30.08 (4652). 2 For high temperature reflow parts see 78250J Series. (0.600.15) (12.95) Tube material: Antistatic coated clear pvc. 0.22 (5.50) 0.15 (3.80) 0.62 (15.70) www.murata-ps.com/support KMP 78250C C07 Page 2 of 3