Surface Mount Coils: HF-Q3 Series

Source: Coil-Q Corporation
Industry Standard Replacements
At Coil-Q we can custom design any coil. We find solutions for the hard to find, complex, discontinued, retrofit utilizing industry standard forms.

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Specifications: Q3SMT-Series HF Coils
Mechanical Drawing: Q3VSMT-Series VHF - UHF Coils

Our coils and transformers are designed to suppress parasitics (IP3, distributed capacitance,cross talk,etc.)while maintaining High Reliability, High Q and a Low Temperature Constant. This is the best place to start when designing Filter and Precise circuits for RF.


  • Rugged surface mount
  • Customizable
  • Mil Quality at a Commercial Price
  • Highest Q for its size without the use of ferrites
  • Seated in epoxy for moisture protection
  • Magnetic and electrostatic shielding
  • Very low TC<35 PPM / ° C
  • Very low distributed capacitance (high Fo)
  • Designed to meet Mil-C-15305 C, Grade 1
  • Available in two sizes
  • Compatible with high temperature soldering and all cleaning processes


  • Pins are tin plated.
  • Coil base is made of temperature resistant DAP.
  • Coil form is made of gloss woven polyester.
  • The core structure of the coil consists of cup core and a threaded center core which combine to give good magnetic shield.
  • Both core elements are made of powdered iron, to minimize performance variation with temperature.
  • Electrostatic shield consists of a copper can, tin plated.


The Q3SMT Series inductors are available in the standard .445in high, (tuneable +/- 10%), or the flat top .42in high, (tuneable +/- 7%). Please specify the package height when ordering.

The inductance adjustment range of Q3 type coils was deliberately stated below the attainable values by mechanically adjusting capability, in order to keep Q variations below 7%. Of course a larger adjustment range is possible if Q variation is not of great importance to the circuit.

Inductance and Q of the HF coils were measured on the HP 4323A Q meter. Data was obtained by the use of soldered leads, in order to avoid errors due to contact resistance.

Please note that the VHF-UHF coil inductance is indicated in nanohenires. The HF portion of the listing is stated in microhenries.

Coil Q products are RoHS compliant.

Made in the USA since 1968.

Click here to download product specifications for Coil-Q Corp.'s complete line of Q3SMT-Series HF coils.