| 摘要 |
An improved passive double balanced mixer with reduced capacitor voltage mismatch is described. A passive double balanced mixer includes two sets of mixer circuits, each comprised of switches. Each switch is separately divided into a first portion and a second portion of unequal number of fingers. A first and second LO AC coupling capacitors associated with a given switch are coupled at one end to an LO signal. The outputs of the first LO AC coupling capacitors are coupled to the first portion of the first switch and the second portion of the second switch, respectively, while the outputs of the second LO AC coupling capacitors are coupled to the second portion of the first switch and the first portion of the second switch, respectively. In one embodiment, the unequal number of fingers is defined by an n−1 and an n+1 number of fingers, respectively. In an alternate embodiment, the mixer is an ADB mixer with a transconductance amplifier and two sets of mixer circuits as above. |
