Lid Attach


APPLICATION NOTE: Plastic Cap Lid Attachment

StratEdge lids are provided with an attached epoxy preform. Store lids in a clean, dry environment. Lids have a shelf life of 6 months if stored at room temperature and a shelf life of 12 months if stored at +5°C or lower (refrigerated). Cap lids are installed as follows:

1. Preheat oven to 155-160°C.
2. Allow cap lids to warm to room temperature before proceeding.
3. Handle using tweezers or finger cots in a clean area to avoid contamination.
4. Position cover on the package and secure with a spring clip. Based upon the external perimeter of lids with .020" walls, for perimeter up to 1.4", use 1 lb. spring clip, and for perimeter up to 2.8", use 2 lb. spring clip.
5. Cure clamped parts for 1 hr.
6. Remove the assembly from the oven and remove the clips.

Cleaning of cap lids before assembly is not recommended!

For further assistance, contact Applications Engineering @ 858-569-5000, or by e-mail at Applications@StratEdge.com

Mounting LPAs On Circuit Boards

APPLICATION NOTE:
Mounting assembled Leaded Power Amplifier (LPA) Packages onto circuit boards.


Special design considerations allow the LPA Packages to operate at high frequency. LPA packages feature leads attached to an alumina ceramic body with one of the strongest ceramic to metal joints available. One element required for operation at high frequency is the use of fine geometry leads. Fine geometry leads are not as robust, and it is possible to exceed the yield or tensile strength even with small hand tools. Even though firmly attached, EXTRA care in handling is essential.

"Do"s

Check all fixtures used for assembly, for lead form, and for test to be sure that parts are not subjected to unnecessary physical stress.

Check that fixtures allow for proper tolerance accumulation.

Check that test sockets are easy to load, and not likely to torque or twist the leads.

For packages that mount with screws, be sure that the package is attached to a flat surface.

"Don't"s

Do not over-torque mounting screws.

Do not use conductive gaskets or shims under the package.

Do not use test fixtures or sockets that may produce a sharp lifting force to lift the lead directly adjacent to the package.

If packages must be removed after solder attach, do not pry the leads up so that the force lifting the lead from the board is also lifting the lead from the package. Use a probe to press down on the lead-to-package joint, and lift the lead when the solder is fluid.

Package Assembly

APPLICATION NOTE: Leaded Power Amplifier (LPA) Packages - Plastic Cap Configuration

Wire/Ribbon Bonding and Test: StratEdge LPA packages feature Nickel - Gold plated metallization, and are designed to match with a raised plastic cap using an epoxy preform. Conventional wedge bonding is recommended for optimal chip performance, and soldering is recommended for the lead attachment. Typical leads are .010" wide X .005" thick. Extra care in handling is advised, especially if your facility is accustomed to larger leads. Terminate unused RF I/Os to the base to minimize coupling.

Cleaning: Although all packages are thoroughly cleaned before shipment, if additional cleaning is desired, the recommended procedure is the use of a commercial organic degreaser followed by acetone and isopropyl alcohol.

Rework: If components need to be removed from the package, the package should not be heated above 400°C.

For further assistance, contact Applications Engineering @ 858-569-5000, or by e-mail at Applications@StratEdge.com

Screws for Mounting LPA Packages

Product Name Length, min Length, min Thread Pitch Thread Tolerance Material Torque, in-oz
Socket Head Cap Screw, English 1/8" 0 80 Class 3A Type 316 Stainless Steel 1.0
Socket Head Cap Screw, English 1/8" 2 56 Class 3A Type 316 Stainless Steel 2.0
Socket Head Cap Screw, English 6 mm M1.6 0.35 mm 4g6g Type 316 Stainless Steel 1.0
Socket Head Cap Screw, English 6 mm M2.5 0.45 mm 4g6g Type 316 Stainless Steel 2.0

1. Mounting surface should be tapped for close tolerance fit of inner to external thread.
2. Mounting surface must be flat.
3. Any bending or deformation of the package during mounting is likely to damage the ceramic. To avoid this:
3.1. Insert all mounting screws for a given package and tighten all finger tight.
3.2. Begin tightening screws on opposite corners of the package to 1/3 torque
3.3. Tighten following same screw position pattern to 2/3 torque
3.4. Tighten following same screw position pattern to full torque
4. The use of ground or thermal pads under the package is NOT recommended.
5. The use of low tack, ductile adhesives to improve grounding and thermal performance has not been investigated by StratEdge. Customers considering this mounting should consider a package design with a thicker, stiffer base.