1. The simple functional diagram of Analog Devices’ ADRF5046 SP4T switch, which operates to 44 GHz, doesn’t show critical design-in issues such as parasitics and S-parameters.
The reflective switch design features insertion loss of 1.5, 2.5, and 3.0 dB at 18, 40 , and 44 dB, respectively, along with isolation of 46, 33, and 31 dB at those frequencies. Linearity is also a critical parameter; typical values for the ADRF5046 are 27.5 dBm (P0.1dB) and IP3 of 50 dBm. The switch handles RF power levels to 27 dBm for both through-path and hot-switching modes.
The five RF ports (common plus four switched) are dc-coupled to 0 V, so no dc blocking is required at the RF ports when the RF line potential is equal to 0 V. Furthermore, the RF ports are internally matched to 50 Ω, limiting the need for external matching networks.
The integrated drivers implement logic functions and offer a simple CMOS/LVTTL-compatible control interface where two digital-control inputs establish the RF path. The switch design is bidirectional with equal power-handling capabilities. At these frequencies, size matters, as smaller size minimizes parasitics and interconnect issues that will always be present. However, its 20-terminal, 3- × 3-mm LGA package should help here.