Low noise amplifier and differential amplifier

摘要

In a double-loop negative feedback low noise amplifier having double negative feedback paths by a feedback transformer (23) and a feedback resistor (44) added to a cascode amplifier comprising transistors (24, 27) and a resistor (30), a phase compensation circuit comprising a capacitor (42) and a resistor (45) is added between the output terminal of the double-loop negative feedback low noise amplifier and the input terminal of the cascode amplifier, i.e., the input terminal of the input transistor (24), and a phase compensation circuit comprising a capacitor (43) and a resistor (28) is added to the upper-stage transistor of the cascode amplifier, i.e., the input terminal of the upper-stage transistor (27). Those phase compensation circuits enable a low noise negative feedback amplifier which maintains a high feedback loop gain to a high frequency band, has a wider bandwidth than a conventional one, and has a high dynamic range.