A 300-MHz quadrature direct digital synthesizer/mixer in 0.25-μm CMOS

A 300-MHz quadrature direct digital frequency synthesizer/complex mixer (QDDSM) chip is presented. With a 32-bit input frequency control word, the tuning resolution is 0.07 Hz at the operating frequency of 300 MHz. The 12-bit I and Q inputs and 13-bit I and Q outputs offer a spurious-free dynamic range of 90.3 dB. The tuning latency is 13 clock cycles, which corresponds to 43 ns at 300 MHz. The tuning bandwidth (half the operating frequency) is 150 MHz. The IC is realized in 0.25- mu m TSMC CMOS technology with 4180 standard library cells and occupies a core area of 0.36 mm super(2). At 300 MHz, the power dissipation is less than 400 mW. A key feature of the design is the creation of conditionally negating multipliers.