Browse Prior Art Database

Guardbanding Card Assemblies Within the Manufacturing Line

IP.com Disclosure Number: IPCOM000122654D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Bowen, SO: AUTHOR [+2]

Abstract

Disclosed is a method of monitoring a product's operational performance during a normal manufacturing test. By monitoring this performance beyond product specifications, marginal products with a high probability of failure can be identified and statistically understood before shipment. The impact of engineering changes, component second sources, and process variabilities can be analyzed.

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Guardbanding Card Assemblies Within the Manufacturing Line

      Disclosed is a method of monitoring a product's
operational performance during a normal manufacturing test.  By
monitoring this performance beyond product specifications, marginal
products with a high probability of failure can be identified and
statistically understood before shipment. The impact of engineering
changes, component second sources, and process variabilities can be
analyzed.

      The data acquisition equipment, A of the figure, preconditions
the assembly to a predetermined temperature. The card assembly is
then functionally tested while maintaining the assembly at that
temperature.  The assembly is then preconditioned at temperature two
and tested again. The preconditioning temperatures are typically set
outside both operating limits of the product, i.e., +70 Celsius and 0
Celsius, and the test software for the Guardband data is the same
test software as used for the specification limits.

      Referencing B of the figure, the card assembly is tested at a
randomly selected voltage above the specification voltage at the high
temperature. This random test voltage is chosen between the upper
specification limit and the upper Guardband limit which is
established by previous Guardband tests.  The upper Guardband limit
is below any destructive voltages that may cause damage to the
product under test.  Once the Guardband data point has been acquired
the product is then tested at the u...