| 摘要 |
PURPOSE:To reduce the crosstalk between channels by providing P/N channel MOS transistors (TRs) among CMOS switches connected in series and parallel for two each and applying ON/OFF control in the reverse state as the CMOS switches to the TRs. CONSTITUTION:In giving an abnormal voltage below a ground potential (Vss)-Vf (diode forward voltage) to a channel CHphi, currents i1, i2 flow respectively from connecting points A, B. Although the relation of currents i1>i2 exists, the current (i) flowing to the channel CHphi is nearly equal to the current i1. Thus, the voltage drop from the Vss is slight at a point B, and the level at both points A, B is not below Vss-Vf and a parasitic NPN TR of the CMOS switches 132, 142 toward the NMOS is not turned on. Thus, the effect onto a common output line 12 is not caused at the L level state of the control signal. Moreover, when an abnormal voltage over Vdd+Vf is inputted to the channel CHphi, the current (i) flowing form the channel CHphi is nearly equal to the current i2, the level is not over Vdd+Vf at both the points A, B and the switches 132, 142 are not turned on.
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