| 摘要 |
A low noise differential amplifier includes a differential stage and first and second unbalanced differential feedback amplifiers. The differential stage includes first (13) and second (14) load devices coupled to first (11) and second (12) conductors, respectively, a resistor (RS), a first input transistor (Q1) having a first electrode coupled to the first conductor and a second electrode coupled by a third conductor (16) to a first terminal of the resistor (RS), and a second input transistor (Q2) having a first electrode coupled to the second conductor (12) and a second electrode coupled by a fourth conductor (17) to a second terminal of the resistor (RS). The first feedback amplifier (18) includes a third input transistor (Q5) coupled between the third conductor (16) and the first current source transistor (Q3) and having a gate electrode coupled to receive a first input signal (VIN+). The first feedback amplifier (18) drives the control electrode of the first input transistor (Q1). The second feedback amplifier (19) is identical to the first, and receives a second input signal (VIN-), and drives to control electrode of the second input transistor (Q2), the second feedback amplifier (19) producing a second signal (25) on the control electrode of the second input transistor (Q2). A first current source produces a first bias current through the first load device (13), the first input transistor (Q1), and the third input transistor (Q5). A second current source similarly produces a second bias current flowing through the second load device (14), the second input transistor (Q2), and the second feedback amplifier.
|
