LARGE VALUE X2Y® IN DC-DC CONVERTERS

All commonly deployed DC-DC converter topologies: Buck, boost, flyback, SEPIC (Cuk topology is rare)

have at least one switched port. Parasitic capacitance across filter inductors passes

high frequency switching noise to filtered ports HF noise propagation through filtered and switched

ports is proportional to filter capacitor mounted ESL at each.

The unique construction of X2Y® capacitors results in essentially constant mounted ESL in larger body parts such as 1206, as in smaller body parts such as 0603.

Enables massive improvement in filter performance w/o extra magnetics

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LARGE BODY X2Y® IN DC-DC CONVERTERS

Example 1206 body part

uStrip configuration, mounted ESL < 40pH

> 25:1 HF noise attenuation versus well-mounted 1206 MLCC @ 1nH

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X2Y 1206 sizeon microstrip

|S21| Transfer Impedance, 1206 Size X2Y®

10uF RatedCapacitive Line

Microstrip Filter Performance

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1- X2Y 2-X2Ys

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DC-DC Converters

X2Y® Low ESL attenuates HF spikes at both input and output nodes for all common topologies: Buck Boost Flyback SEPIC

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DC-DC Converters

Filter parasitics pass HF noise often 200MHz or more to output

Solutions: Add series filters

Cost Space DC drop

Reduce filter capacitor inductance

Conventional 1206 caps > 1nH ESL

X2Y® 1206 caps, very low mounted ESL: 35-120pH

10X – 25X+ better than conventional 1206

Value depends on mounting configuration

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DC-DC Converters

X2Y® low ESL shunts HF noise:

Noise “Brick Wall” Reduced EMI from

converter into application PCB

Reduced EMI from application PCB conducted back through converter

No extra magnetics Reduces cost for

performance Saves space No extra DC drop

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Example Buck DC-DC Converters Input Filter

X2Y® Location

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DC-DC Radiated Emissions from DC Feed

DC-DC Converters

Design Assistance

X2Y provides design assistance: Application specific support Whole product circuit recommendations

for IC bypass / EMI filtering, to maximize component reduction and performance

Models, simulations, documentation

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