Optimized High Voltage Analog Switch IC using Low Breakdown SOI Technology

Low ON-resistance high voltage analog switch ICs are mainly used for ultra sound imaging system. Recently, high voltage analog switch is widely applied to inkjet printer driver and electrical control systems. In previous works using bulk process, gate oxide thickness should be thicken to guarantee breakdown voltage to operate switch over 250V. In this paper, Conventional SOI process Lateral High voltage MOSFET (LDMOS) with low Gate-Oxide breakdown is used for low ON-resistance analog switch. For the isolated bi-directional analog switch, Solid State Relay (SSR) structure was adopted and the level shifting includes the circuits to clamp the gate voltage. In addition, using HV-CMOS technology, analog switch combines high voltage bilateral DMOS switches and low power CMOS logic to provide efficient control of high voltage analog signals. We adopt high voltage BCD-SOI process to produce very efficient isolation characteristic and it can be high channel density for greater performance in less space.