Digital/analog (D/A) converting device with unit current generating circuit having differential switching and reference voltage generating circuits

摘要

The D/A converting device disclosed includes a decoder (1), and a plurality of unit current generating circuits (2A-2G) each having a differential switching circuit (15) and a reference voltage generating circuit (18). The decoder (1) receives a digital input value of n bits and outputs a plurality of complementary pairs of digital signals corresponding to the n bits of the digital input value. Each unit current generating circuit (2A-2G) receives a complementary pair of digital signals from the decoder. The differential switching circuit (15) has two complementary current output terminals (8A,8B), a bias voltage input (10B) and a reference voltage input (11'). The two complementary current output terminals of the differential switching circuit are interconnected between corresponding ones of the unit current generating circuits with the interconnected points being made two complementary analog output terminals (4,5). Each of the analog output terminals and a power source terminal (6) are connected to a load circuit (RL), whereby analog output voltages corresponding to the digital signals inputted to digital input terminals (3A-3C) of the n bits are obtained at the analog output terminals. This enables the speeding up of a settling time by reducing overshoot and undershoot when the analog output full-swings.