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      Design


             What can be embedded?



























        Design Criteria


             The designer should try and keep the "pull-ups" and "pull-down" resistor values as low as possible.
                       • 10K pull down >>> 1K
                       • 10K pull ups >>> 4.7K, 3.3K, 2.2.K
             To reduce cell size.
             Mostly to be used in digital designs
             For precise values (1%) trimming is required
             Better functionality as we lower the inductance from:
                       • 0.9 nH in a1206 SMT resistor, to:
                       • 0.4 nH for an embedded resistor
             Because of its thin film 0.1-0.4 micron, it can be buried within layers without increasing the PCB thickness
             The estimated failure rate is less than 0.001 resistor elements per 1 million operating hours
             The cost benefit starts once the resistors density is 3-4 resistors/square inch of a board


        Schematic


             During the design phase of the schematic capture, the typical electrical engineer will not see any flow change
             You place the buried resistor in the schematic like any part
             If you maintain the "PCB footprint" column, there you will insert a different resistor shape

 

 

 

 









        BOM

             Purchase will get a BOM of all passives
             Manufacturer will get a list of all embedded resistors, reference designators, value, material, layer and location

        CAD Libraries

             The Librarian will create embedded components that typically include a material property and a fabrication technique property
             The geometries will be created in different layers for different materials
             The geometries will indicate that the component is embedded
             It is important to generate a library scheme so that unique cells are not needed for every specific value
             Silk screen outline is not required
             Placement and route obstructs are required

        PCB Footprint example:

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