DA conversion device and electron beam exposure system using the same

摘要

A DA conversion device (10) includes a current output type DA converter (11), a high-speed operational amplifier (12) operating at a low voltage and configured to generate a voltage corresponding to an output current from the DA converter (11), and a buffer amplifier (13) connected to an output terminal of the high-speed operational amplifier (12) and operating at a high voltage. The device (10) also includes positive and negative floating power supplies (14a, 14b) separated from a power supply system (18a, 18b) and provided as power supplies for driving the DA converter (11) and the high-speed operational amplifier (12). A midpoint (14c) between potentials at the floating power supplies (14a, 14b) is connected to an output terminal of the buffer amplifier (13) to cause the DA converter (11) and the high-speed operational amplifier (12) to operate mainly based on an output voltage from the buffer amplifier (13).