LODESTONE PACIFIC is both manufacturer and distributor of products and services for the magnetics segment of the electronics industry. The company is structured to offer the highest quality product and service at the lowest total cost, and is committed to substantial inventory that insures competitive advantage through quick shipments and tightly scheduled delivery.

Used in tuned radio frequency applications for over 25 years as RF Filter Inductors, Oscillators, and Narrow and Broad Band RF Transformers, these variable assemblies have been proven extremely reliable in military, aerospace, specialty and consumer electronic applications requiring high Q and durability with temperature and time.

PART NUMBERING SYSTEM

There are fourteen series of Lodestone Pacific shielded coil form assemblies; L20, L30, L32, L33, L335, L337, L39, L3901, L40, L41, L42, L43, L45 and L57. Each series consists of a base or header with terminals, a winding form, a tunable threaded core and a shielding cup both made from a magnetic material, and a metal shield can.

A typical part number consists of five groups of alpha-numeric codes.

Each series offers up to eight iron powder or ferrite material mixes engineered to optimize inductance and Q within a specific frequency range. The magnetic material that makes up the tuning core and cup core have a part number which includes the mix number that matches the mix number for an entire assembly part number.

L57-2-CT-B-4 is a L57 series assembly utilizing iron powder mix 2, which is suited for tuned circuit applications from 250 Khz to 10 Mhz.

ASSEMBLY CHARACTERISTICS

Base and Terminals: The plastic base is thermoset DAP which has a flammability rating of UL94-VO and will tolerate temperatures up to 750ºF, The high temperature resistance of the DAP material is ideal for using a solder pot and heat-stripping coated magnetic wire to form the winding lead to base termination. The exceptions are the L20, L30 and L41 series which are moulded in a cost effective glass filled nylon or polycarbonate which can tolerate 500ºF for a brief period. The terminals in all assemblies are half hard brass or copper wire plated to MIL-T-10727 and tested to MIL-STD 202, Method 208 for solderability.

Magnetic Materials: Iron Powder offers great repeatability and stability. The inductance tolerances of iron powder is ± 2% within a production lot and ± 5% from lot to lot. The ferrite materials listed are manufactured to ± 10% within a production lot and ± 20% from lot to lot. Click here for a description of the temperature characteristics for these materials.

The tuning cores of the variable assemblies have shallow threads and driver slots that conform to Metal Powder Industries Federation standards. Each threaded core is coated with Teflon to insure smooth reliable tuning with a torque of between . 5 to 2.5 inch/oz. Tuning Tool A or an equivalent is recommended to insure drive slot integrity.

Winding Forms: The coilforms and bobbins are designed to offer several winding options on materials selected for their durability and stability. A description of these winding forms is included on the data sheets for each Shielded Coil Form series.

Shield Can: All shield cans are copper for maximum shielding and Q performance. The exceptions are the L20, L30, L40 & L41 series which are made from a more cost effective brass. All shield cans are tin plated to MIL-T-10727 which specifies the plating composition and thickness. The grounding tabs on the shield cans meet MIL-STD 202 Method 208 for solderability.

Anti-vibration Pads: Lodestone Pacific offers an optional silicone rubber pad used in some assemblies to squeeze the components together when crimped into the shield can. These anti-vibration pads will improve the durability of the assemblies in extreme environments.

AVAILABILITY:

Lodestone Pacific sells entire assemblies or any of the individual components that are a part of an assembly. Individual components are traditionally in stock as are small quantities of completed assemblies. Samples of components or complete assemblies are available from stock. Ask us about configurations your don't see in this catalog.

QUALITY CONTROL:

Lodestone Pacific's internal quality control and inspection system follows guidelines found in MIL-I-45208A, ISO 9000 and MIL-STD-2000. Testing, inspection and research is done on a Hewlett Packard 4191A or 4277A LCZ meter for inductance and a Hewlett Packard 4342A and a Boonton 190A for Q.

Solderability of the base terminals and the shield can tabs meets or exceeds the solderability standards found in MIL-STD-202, Method 208. Storage and handling is in accordance with MIL-STD-2000.