A divider used to provide six local oscillator signals for harmonic rejection mixer

In this paper, by analysing the requirement of input LO signals sending to a harmonic rejection mixer (HRM), a divider is designed for HRM, which is used to supply six LO quadrature signals with a phase shift of 45° to cancel the 3th and 5th order harmonics. The divider consists of four D flip-flops which is constructed by two master-slave latches, and the highest operating frequency is inversely proportional to the maximum delay path. And it can operate well over a wide range of 800MHz-1.6GHz. This kind of divider can provide output signals with better stability and improve the match characteristic so that the phase error is less than 1°. Because of the small phase error, harmonic rejection 3th and 5th are better than -50dBc. The divider draws a current of 1.2 mA under 1.8-V supply voltage, fabricated in a 0.18-μm CMOS process with a layout area of 0.0273mm2.