Lsi Logic Corporation

Lsi Corporation

Lihui Cao

Weidan Li

Maad A Al-Dabagh

Prasad Subbarao

David Gradin

Peng Rong

A fast active DCAP cell which has a short turn-on time, achieves a high capacitance density, and which minimizes leakage overhead during its normal operation mode is disclosed. The DCAP cell has a pair of PMOS transistors that have their drains connected to a gate of a PMOS transistor and their sources connected to the VDD rail. The drain and source of the PMOS transistor are connected to the VSS rail. Likewise, the DCAP cell has a pair of NMOS transistors that have their drains connected to a gate of an PMOS transistor and their sources connected to the VSS rail. The drain and source of the PMOS transistor are connected to the VDD rail. None of the gates of the transistors is connected to the VDD or VSS rail. This protects the gate oxide from being damaged by ESD surge currents.

Fast turn on active DCAP cell

A method for estimating decoupling capacitance during an ASIC design flow is disclosed. The method includes precharacterizing a set of power grid structures to model their respective noise behaviors, and storing the respective noise behaviors as noise factors in a table. During the ASIC design flow for a current design that includes at least one of the precharacterized power grid structures, the corresponding noise factor from the table is used to calculate decoupling capacitance for the current design.

Decoupling capacitance estimation and insertion flow for ASIC designs

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Lihui Cao