| 摘要 |
PURPOSE:To directly operate a loudspeaker by an output signal of a 1-chip LSI circuit by a method wherein a bipolar transistor circuit is integratedly formed in the LSI in which MOS circuit for the sound data precessing is formed. CONSTITUTION:An N<-> type semiconductor substrate 5 is formed with a resistor 7 for D/A converting circuit and a base region 8 of an NPN-transistor by the same process as that of diffusing a P<->-well 6 for forming an N-channnel MOS transistor. An emitter region 9 of the NPN-transistor is formed simultaneously with an N type impurity diffusion process for a source and drain 10 in the P<->-well. The resistor is allowed to be formed at the same time as the formation of a P-channel transistor. A circuit from which a large current analog signal is fed can integratedly be formed by utilizing the process of CMOS. |
