Patent ID: 7352241

Claim:
A variable gain amplifier, comprising: a first cascode amplifier which comprises a first common source transistor, a first common gate transistor, and a third common gate transistor; a second cascode amplifier which forms a differential pair with the first cascode amplifier and comprises a second common source transistor, a second common gate transistor, and a fourth common gate transistor; a first gain adjustment unit having a side coupled to a drain of the first common source transistor and a source of the first common gate transistor and another side coupled to a drain of the second common source transistor and a source of the second common gate transistor; and a second gain adjustment unit having a side coupled to a drain of the first common gate transistor and a source of the third common gate transistor and another side coupled to a drain of the second common gate transistor and a source of the fourth common gate transistor.