Reliable PCB Assembly of Land Grid Array Packages in Planar Phased Array Antennas

High frequency planar phased arrays often require a complexity from their beamforming ICs and transmit/receive (T/R) modules that force the devices into high pin-count land grid array (LGA) packages, so that all the RF circuits fit into a λ/2 lattice spacing. LGA packages have recessed pins located on their bottom side. As a result, PCB solder mask variation and solder volume invariance both contribute to difficult PCB assembly if the LGA footprint is not designed correctly. This article gives guidelines for proper LGA footprint design that leads to high yield PCB assembly and gives a practical LGA footprint design example using the large, high pin-count ADAR1000 beamformer IC.