DIFFERENTIAL AMPLIFIER AND DIGITAL-ANALOG CONVERTER

摘要

PPROBLEM TO BE SOLVED: To provide a differential amplifier avoiding an effect by a power supply, signal noises and switch noises and being capable of arithmetically outputting a plurality of input reference voltages. PSOLUTION: The differential amplifier has input terminals (1, 2 and 3), an output terminal (4) and paired transistors (531, 532) and (533 and 534) as first and second differential pairs connecting their outputs to load circuits (537 and 538) in common. The differential amplifier has an amplifying stage (539) having an input end connected to one of connection points among the load circuits, and outputs from the first and second differential pairs and having an output end connected to the output terminal. A signal from the third input terminal and the output terminal are input to the second differential pair, and the differential amplifier has switches (SW1 and 2) among the inputs to the first differential pair and the input terminals (2 and 3). The differential amplifier has the input pair of the first differential pair and capacitors (C1 and C2) connected among each connecting point for the switches (SW1 and 2) and a reference voltage. The voltage may also be input serially while using input terminals (1, 2 and 3) as one terminal. PCOPYRIGHT: (C)2007,JPO&INPIT