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EMI Filter Installation Guidelines

Threaded Style EMI Filters

 
  • Exceeding recommended mounting torque may cause damage to the capacitor within the filter because of possible twisting or elongation of the case.

  • For products without hex surfaces, do not hold the filter with pliers or other gripping tools. Pressure exerted on the filter case may crack the ceramic capacitor element.

  • Proper use of filters requires that the filter case be adequately grounded to form an effective path for the interference.

 

Solder-in Style EMI Filters

  • A controlled temperature profile not exceeding 6°F (3°C) per second is recommended when soldering filters.

  • When soldering to terminals of a filter, a heat sink should always be used adjacent to the body of the filter.

  • 60-40 solder is recommended for installation of the filter into the chassis and soldering to the terminals. If a filter style without an eyelet is being soldered into a chassis, iron processes should be avoided and the recommended solder alloy is 60-38-2.

  • Installation hole size for a solder-in filter should be 0.003-0.005” over the maximum tolerance of the minor diameter of the mounting portion of the eyelet with a ±0.002” tolerance.

  • Machine/oven soldering 385-415°F (195-210°C) using a dwell and cycle time fast enough to reflow the solder and ramped to maintain less than 6°F/sec rate of change.

 

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  • For iron soldering to filter body, preheat components at 250-300°F (120-150°C), solder iron is recommended to be set at 500-550°F (260-290°C). The dwell on the solder joint should be less than 5 seconds. The time depends on the heat sinking provided by the chassis, so a longer preheat may be required.

 

Soldering to EMI Filter Terminals

  • Use a temperature controlled soldering iron with tip temperature of 525 ± 10°F (275 ± 5°C).

  • Use an SN 63 RMA flux core solder.

  • Make mechanical wire connection.

  • Use heat sink next to filter body where possible.

  • Clean soldering iron tip.

  • Clip end of solder (remove 0.5”) to expose flux for soldering.

  • Apply soldering iron to wire/flag junction at wetted solder tip region of iron (Wetted Bridge Method). Immediately apply solder. Dwell time for soldering iron tip on product should be 3-5 seconds maximum.

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