| 摘要 |
PURPOSE:To form LSI of one chip and thereby miniaturize and simplify the device by preparing an output circuit for forming an analog signal by utilizing the process of preparation of CMOS. CONSTITUTION:When a P<-> well is diffused to form an N channel MOSFET on an N<-> substrate 6, a resistance 7 for a D/A convertion circuit 2, a resistance 8 connected with a P channel MOSFET 3 and a base layer 9 of an n-p-n transistor are prepared. An emitter layer 10 of an n-p-n element is formed simultaneously with the N diffusion of a source drain 11 in the P well. Consequently, each layer is connected with other layers in a prescribed manner, whereby the output circuit is formed monolithically in LSI. By this constitution, the LSI circuit applied, for instance, to a voice synthesizing system can be formed within one chip, whereby the device can be miniaturized and simplified and a speaker can be driven at once by an output signal from LSI. |
