High-performance PQFP

The design of a high-performance plastic quad flat back (PQFP) is described. It is a multilayer package designed to provide a high level of electrical and thermal performance. The design maintains the JEDEC standard package outline; the changes are internal to the plastic body of the PQFP. A pair of parallel metal planes is added to serve as the power and ground paths for the device. By replacing a substantial portion of the highly inductive leads by the plane and shorting all V/sub cc/ or V/sub ss/ leads through their respective planes the power-group loop inductance is reduced significantly. The planes increase the power-ground capacitance by approximately 500% while lowering the capacitive coupling between leads. The planes spread the heat generated by the IC chip over the total area of the package, reducing the package thermal resistance and eliminating the need for internal heats conductors.<>