The ADG738 and ADG739 are CMOS analog matrix switches with a serially-controlled 3-wire interface. The ADG738 is an 8-channel matrix switch， while the ADG739 is a dual 4-channel matrix switch. On resistance is closely matched between switches and very flat over the full signal range. FUNCTIONAL BLOCK DIAGRAMS Figure 1. Figure 2. The ADG738 and ADG739 utilize a 3-wire serial interface that is compatible with SPI?， QSPI?， MICROWIRE?， and some DSP interface standards. The output of the input shift register， DOUT， enables a number of these parts to be daisy-chained. On power-up， the internal input shift register contains all zeros and all switches are in the off state. Each switch conducts equally well in both directions when on， making these parts suitable for both multiplexing and demultiplexing applications. As each switch is turned on or off by a separate bit， these parts can also be configured as a type of switch array， where any， all， or none of the eight switches may be closed at any time. The input signal range extends to the supply rails.