AN207

Each AN207 device has four independently controlled switches. The DG611 and DG612 respond to opposite control logic. The DG611 has a normally closed (NC) function while the DG612 is a normally open (NO) device.

The AN207 offers a complementary function. It contains two NO and two NC switches. This versatile device can be configured as two single-pole single-throw (SPDT), one double-pole double-throw (DPDT), a "T" switch, two "L"switches, and so forth.

As illustrated in Figure 2, each analog switch channel consists of an input stage, followed by a level translator, a driver stage, and an n-channel MOSFET.

The input stage is a CMOS inverter powered from VL. VL is the logic power supply voltage (normally +5 V). As with any classic CMOS inverter, control input pin impedance is very high and essentially equivalent to the logic input pin capacitance (approximately 5 pF). This pin does not draw current (except for leakage) when in a steady state. To change states it is necessary to charge or discharge this input capacitance, which requires a short current pulse from the control logic gate.