What is the difference between a QFN, a LGA, and a BGA package for RF components?

QFN (Quad Flat No-lead), LGA (Land Grid Array), and BGA (Ball Grid Array) are three SMT package types commonly used for RF components, each with distinct characteristics for thermal performance, RF grounding, frequency capability, and assembly. QFN uses flat copper leads on the package bottom edges plus a large exposed thermal/ground pad. It provides excellent thermal performance (direct die-to-pad heat path), low parasitic inductance (short, flat leads), and easy visual solder inspection. QFN is the most popular package for RF amplifiers, switches, and ICs below approximately 10 GHz. Typical sizes: 3x3 mm to 7x7 mm. LGA uses flat pads (lands) on the package bottom instead of solder balls, resulting in a profile even lower than BGA. LGA provides moderate I/O density, good thermal performance, and is reworkable (unlike BGA which requires reballing). LGA is common for RF front-end modules (combining PA, LNA, filter, switch). Typical sizes: 2x2 mm to 10x10 mm. BGA uses an array of solder balls on the package bottom for highest I/O density. BGA provides the most interconnections (hundreds to thousands), good self-alignment during reflow, and handles complex multi-function ICs with many signal and power connections. BGA is used for complex RF SoCs, transceivers, and multi-chip modules. Lead parasitic inductance is slightly higher than QFN due to longer internal routing.