MQME-270-P
Current: 2A
Technical Specification
BASICꢀOPERATIONꢀANDꢀFEATURES
TheꢀMQME-270-Pꢀisꢀaꢀmulti-stageꢀdifferential-modeꢀandꢀcommon- Whenꢀ usedꢀ withꢀ SynQor’sꢀ DC/DCꢀ converters,ꢀ theꢀ MQME-270-Pꢀ
mode passive EMI filter designed to interface a power source with EMIꢀfilterꢀisꢀdesignedꢀtoꢀpassꢀallꢀofꢀtheꢀrelevantꢀMIL-STD-461C/D/Eꢀ
one or more SynQor DC/DC converters (or other loads that create requirementsꢀ toꢀ theirꢀ mostꢀ stringentꢀ limits.ꢀ ꢀ Theꢀ MIL-STD-461ꢀ
EMI).ꢀꢀEachꢀstageꢀofꢀthisꢀfilterꢀisꢀwellꢀdampedꢀtoꢀavoidꢀresonancesꢀ ComplianceꢀMatrixꢀTableꢀonꢀPageꢀ7ꢀlistsꢀtheseꢀrequirementsꢀandꢀ
andꢀoscillations,ꢀandꢀonlyꢀX7Rꢀmulti-layerꢀceramicꢀcapacitorsꢀareꢀ describesꢀtheꢀsetupꢀusedꢀtoꢀpassꢀthem.ꢀꢀFiguresꢀ3ꢀ-ꢀ6ꢀshowꢀresultsꢀ
used.ꢀꢀFigureꢀ1ꢀshowsꢀtheꢀtypicalꢀdifferentialꢀandꢀcommon-modeꢀ from selected conductive and radiated emissions tests.
attenuation provided by this filter when the source impedance is
The filter is also designed to pass the waveform types and
applicationsꢀ specifiedꢀ inꢀ RTCA/DO-160Eꢀ Sectionꢀ 22ꢀ (Lightningꢀ
50Ω to chassis ground on each input line.
TheꢀMQME-270-PꢀEMIꢀfilterꢀincludesꢀaꢀlargeꢀbulkꢀcapacitorꢀ(alsoꢀ Inducedꢀ Transientꢀ Susceptibility)ꢀ toꢀ Levelꢀ 4ꢀ (someꢀ waveforms/
X7R)ꢀwithꢀaꢀseriesꢀdampingꢀresistorꢀtoꢀcorrectꢀforꢀtheꢀunstabilizingꢀ applicationsꢀ requireꢀ theꢀ MQME-270-Tꢀ filterꢀ and/orꢀ externalꢀ
effect of a converter’s negative input resistance. A white paper transientꢀsuppressionꢀcircuitry).ꢀꢀTheꢀSectionꢀ22ꢀComplianceꢀMatrixꢀ
discussing this negative input resistance and the need for corrective Tableꢀ onꢀ Pageꢀ 9ꢀ listsꢀ theseꢀ waveformsꢀ andꢀ applicationsꢀ andꢀ
damping can be found on the SynQor website (see Input System describes the setup used to pass them.
Instabilityꢀapplicationꢀnote).ꢀFigureꢀ2ꢀshowsꢀtheꢀmagnitudeꢀofꢀtheꢀ
filter’s output impedance when the filter input is connected to a stiff
voltage source.
A typical application would place the MQME filter close to the
input of the DC/DC converter, with the cases of the filter and the
converterꢀconnectedꢀtogetherꢀthroughꢀaꢀgroundꢀplane.ꢀꢀBothꢀcasesꢀ
The input voltage surge and spike compliance matrix shown on are electrically conductive, so connection to the cases can be made
Pageꢀ 8ꢀ displaysꢀ theꢀ worstꢀ caseꢀ requirementsꢀ listedꢀ inꢀ variousꢀ with the fasteners used to secure the device.
270VꢀMilitaryꢀ(VehicleꢀandꢀAircraft)ꢀandꢀCivilꢀAircraftꢀstandards.ꢀ
Doꢀ notꢀ connectꢀ theꢀ outputsꢀ ofꢀ multipleꢀ MQME-270-Pꢀ filtersꢀ inꢀ
parallel. Connecting filters in this manner may result in slightly
unequalꢀcurrentsꢀtoꢀflowꢀinꢀtheꢀpositiveꢀandꢀreturnꢀpathsꢀofꢀeachꢀ
filter.ꢀ Theseꢀ unequalꢀ currentsꢀ mayꢀ causeꢀ theꢀ internalꢀ common-
mode chokes to saturate and thus cause degraded common-mode
rejection performance.
TheꢀMQME-270-PꢀEMIꢀfilterꢀisꢀdesignedꢀtoꢀhandleꢀallꢀofꢀtheꢀshortꢀ
durationꢀvoltageꢀspikeꢀrequirementsꢀofꢀtheseꢀstandardsꢀ(withꢀcertainꢀ
assumptionsꢀregardingꢀDEF-STANꢀ61-5).ꢀSomeꢀofꢀtheꢀlongꢀdurationꢀ
voltageꢀ surgeꢀ requirementsꢀ remainꢀ withinꢀ theꢀ 50Vꢀ maximumꢀ
transientꢀ ratingꢀ ofꢀ aꢀ SynQorꢀ MQFL-270ꢀ DC/DCꢀ converter.ꢀ Theꢀ
othersꢀrequireꢀtheꢀtransientꢀsuppressionꢀcircuitryꢀofꢀanꢀMQME-270-Tꢀ
EMI filter to protect the converter from an over-voltage condition. If
MQFL-270EꢀorꢀMQFL-270VEꢀconvertersꢀareꢀused,ꢀvoltageꢀsurgesꢀ
asꢀhighꢀasꢀ80Vꢀcanꢀbeꢀtoleratedꢀwithoutꢀtheꢀneedꢀforꢀthisꢀtransientꢀ
suppression circuitry.
Product # MQME-270-P
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-2ME027P Rev. 2
03/16/09
Page 6
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