Because high operating frequencies of monolithic microwave integrated circuits (MMICs) and multilithic microsystem (MLMS) passive components are demanding higher performance from surface mount packages, RF MMICs and integrated transmit/receive modules supplier Endwave Corp. re-engineered conventional quad flat no-lead (QFN) surface-mount packages to more than double its usable frequency range.
Thus, increasing the upper-frequency limit of QFN housing to 50 GHz and higher.
A standard QFN package is a micro-lead-frame-type surface-mount-technology (SMT) housing designed to provide protection for MMICs and other semiconductors, while also simplifying their attachment to printed-circuit boards (PCBs).
By their design, QFNs allow solder connections directly to PCB traces, without the complexity of fabricating plated through holes (PTHs) in the circuit board. Standard lower-cost plastic-molded QFN packages operate to about 3 GHz, while conventional higher-performance air-cavity QFNs can be used to about 25 GHz.
In this re-engineering, for instance, the lengths of bond wires within the package, used to connect device bond pads to package ports, are minimized wherever possible with the aid of custom laminate sections and a double-reverse-bonding technique.
According to the developer, this results in reduced parasitic circuit elements and higher frequency operation of plastic QFN packages, with lower insertion loss and minimal phase distortion through 50 GHz.
Endwave (News - Alert) characterizes the electrical performance of their enhanced QFN packages by means of calibrated vector network analyzers (VNAs) with millimeter-wave frequency capability. Using specially designed test fixtures to minimize the impact of the test setup on the behavior of the package, the housings are evaluated with and without attached die to optimize package performance for each of Endwave’s MMIC product lines, including its single-function and multifunction MMICs, frequency upconverters and downconverters, amplifiers, and voltage-controlled oscillators (VCOs).