Browse Prior Art Database

Thermal Simulation Module - SMT Resistor Ladder Network

IP.com Disclosure Number: IPCOM000104782D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 1 page(s) / 38K

Publishing Venue

IBM

Related People

Cain, JF: AUTHOR [+3]

Abstract

Disclosed is a module that develops 1.25 watts @ 5 Vdd. This device will be housed in a 144 lead Plastic Flat Pack (PFP) if thermal profiles of the card permit its use. Ceramic packaging or heat sinks will be necessary if the thermal dissipation for the plastic package is not adequate. The procedure and process used to accomplish this task are described.

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Thermal Simulation Module - SMT Resistor Ladder Network

      Disclosed is a module that develops 1.25 watts @ 5 Vdd.  This
device will be housed in a 144 lead Plastic Flat Pack (PFP) if
thermal profiles of the card permit its use.  Ceramic packaging or
heat sinks will be necessary if the thermal dissipation for the
plastic package is not adequate.  The procedure and process used to
accomplish this task are described.

      Create a thermal simulation of the power using a resistor
ladder network that can reside in proximity of the location of the
device.  The use of surface mount technology resistor components was
feasible.  Five one hundred ohm units, in parallel, will generate
1.25 watts of power at 5 Volts (DC).  The following process was
developed that satisfactorily built the thermal modules.

o   Deprocess an existing 144 PFP using a micro milling machine to
    create a cavity.

o   Mill the plastic encapsulation to above the leads.

o   Expose the leads by removing the remaining plastic with fuming
    nitric acid.

o   Mechanically remove the device and header.

o   Place the five SMT resistor diagonally across the cavity.

o   Secure the five SMT resistors with a suitable adhesive.

o   Wedge bond the end cap of each resistor to an appropriate
    interior lead.

o   Refill the cavity with 70% Alumina Filler with Hysol 3028 resin
    and 3416 hardener.

o   Grind the excess "refill" material to arrive at the original
    dime...