Application Note «Fault-Tolerant Analog Switches» (Maxim) - 6

Figure 4. With the MAX338 channel inputs connected to the MAX4507's output pins, they never see more than +15V and -15V, even if voltages ranging from -40V to +40V appear at IN1 through IN8. This circuit provides extremely good fault protection and, at the same time, can switch signals that range up to the power-supply voltages, in this case, ±15V. Also, if the power supplies are interrupted or shut down with input signals present, the circuit continues to protect itself. A single-package device, the MAX4508 (see
Figure 5
) can replace that combined circuit (Figure 4 again). Here, the protection circuitry is built into the chip. Figure 5. Page 6 of 8 Document Outline maxim-ic.com Fault-Tolerant Analog Switches - Application Note - Maxim