A frequency-reconfigurable multi-standard 65nm CMOS digital transmitter with LTCC interposers

This paper demonstrates a CMOS digital polar transmitter with flip-chip interconnection to low-temperature co-fired ceramic (LTCC) interposers. The LTCC interposers contain the PA output balun targeting different operating frequency bands, and the reconfiguration in the carrier frequency is achieved by selecting an appropriate LTCC interposer. The same CMOS core transmitter is reused for different frequency bands. In this design, an output power higher than 22 dBm from 0.6 to 2.4 GHz is demonstrated, with peak power of 27.1 dBm and peak efficiency of 52%. The polar transmitter includes 9-bit phase interpolation and 8-bit amplitude modulation, suitable and verified as a multi-standard universal digital modulator.