National Semiconductor Corporation

Aaron Grant Simmons

Michael E Thomas

Jeffrey Robert Perry

Reda R Razouk

Robert Eric Fesler

Robert A Sabsowitz

Voltage regulators use capacitors to compensate the voltage regulator and provide stable performance. Capacitors have an inherent equivalent series resistance (ESR) that changes over various operating conditions including signal frequency, operating temperature as well as others. An apparatus and method compensates for the low ESR of capacitors to increase the total equivalent series resistance of the capacitor. By providing an &ldquo;on-chip&rdquo; resistance between the capacitor and the circuit ground potential, minimum total ESR can be provided such that stable load regulation is achieved with capacitors that would otherwise be undesirable for such use. Increasing the value of the output capacitor's equivalent series resistance allows wider ranging values of capacitance to be used. The increased range of capacitance values allows capacitors of different material types to be used. Additionally, other arrangements with multiple resistors that are arranged as series resistors between the compensation capacitor and one or more of the power supplies provide stable load regulation.

On-chip resistance to increase total equivalent series resistance

A process for preparing a light-sensitive integrated circuit (IC) for packaging that provides a reduced exposure of the light-sensitive IC to light. The process includes providing a semiconductor substrate (e.g., a silicon wafer) with a plurality of light-sensitive ICs formed in/on its upper surface. The lower surface is optionally coated with opaque material. Next, the semiconductor substrate is diced to form individual light-sensitive ICs, each of which has a semiconductor substrate lower surface and semiconductor substrate lateral edges. The semiconductor substrate lateral edges (and optionally backside) are then spray coated with an opaque material (e.g., opaque ink) to form an opaque layer covering the semiconductor substrate lateral edges. The opaque layer prevents light from entering the semiconductor substrate through the lateral edges and interfering with the operation of the light-sensitive IC. The inventive process is simple and inexpensive, employing, for example, piezoelectric injectors to spray coat opaque ink on the semiconductor substrate lateral edges as the individual ICs are conveyed through a pass-through. In addition, processes according to the present invention are independent of the techniques used to manufacture the light-sensitive ICs and, therefore, provide for increased packaging process flexibility and economy.

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San Jose, CA, United States of America

Aaron Grant Simmons