Frequency mixer with a frequency doubler for integrated circuits

We have developed a bipolar LSI, including a frequency mixer and a local oscillator frequency doubler. The local oscillator frequency doubler consists of two identical unbalanced emitter-coupled pairs with a different emitter area ratio, whose input terminals are connected cross-coupled and whose output terminals are connected in parallel, and is coupled with the frequency mixer directly in the LSI. The fabricated LSI operates on supply voltage as low as 2.7, and has been put into practical use for a cordless telephone system.>