Amplifier suitable for use in a radiotelephone

摘要

The amplifier (201) uses transistors (401,403) such as MOSFET transistors in a current mirror configuration. The transistors (401,403) are easy to package as surface mount devices. The drain port of the first transistor is coupled to an output signal (207) and a bias input signal (VB+). A gate port of the first transistor is coupled to a bias control input (117) and the signal input (115). The source of the first transistor and the source of the second transistor are coupled to an electrical ground (409). A first end of a resistive device (411) is coupled to the gate port and the drain port of the second transistor and a second end of the resistive device (411) is coupled the signal input (115) and the bias control input (117). This amplifier (201) has low sensitivity to the variations of the bias current to the control signal threshold, making the amplifier ideal for use in a radiotelephone (103).