77 GHz CMOS Built-In Self-Test with 72 dB C/N and less than 1 ppm frequency tolerance for a multi-channel radar application

A built-in self-test (BIST) system with 72 dB C/N and less than 1 ppm frequency tolerance of down-converted BIST tone for a multi-channel radar application is presented. The BIST consists of a frequency doubler, an up-conversion mixer, a variable gain amplifier, a phase shifter, 8-way splitter and an RF GSG PAD coupler for BIST signal distribution. The proposed up-conversion mixer can operate from 76 to 77 GHz, mixing with arbitrary offset frequencies from 600 kHz to 42.7 MHz generated by a fully-synchronized PLL. The proposed mixer can cope with a through mode for testability and flexibility improvements as well. Measured relative phase among all of 8 channels were less than 2 degrees from –25°C to 150°C through on-chip 12-bit ADCs. The proposed BIST was fabricated in a 40 nm CMOS process and assembled with a wafer level chip sized package (WLCSP).