High-Voltage, Fault-Protected Analog Multiplexers

The MAX388 8-channel single-ended (1-of-8) and the MAX389 4-channel differential (2-of-8) multiplexers (muxea) with internal data latches use a high-voltage series N-channel, P-channel, N-channel structure that significantly improves fault protection over previous devices. If power is removed with input voltages still applied, all channels turn off, allowing only a few nanoamperes of input leakage current. This protects the mux and output circuitry, as well as the signal sources connected to the channel inputs.

When an overvoltage signal up to ±1 OOV (typically ±11 OV) is applied to an analog input or output, the channel turns off. To further protect output circuitry from on-channel overvoltage, outputs are clamped to less than the power­supply voltage. Since there is no increase in supply current during fault conditions, power dissipation does· not increase. The MAX388/MAX389 withstand full over­voltage on any combination of channels, including all channels simultaneously.

All channel selection and control inputs are TTL and CMOS compatible. And, break-before-make switch operation is guaranteed.

APPLICATIONS

* Data-Acquisition Systems

* Industrial Process Control Systems Avionics Test Equipment

* Signal Routing Between Systems

* Computer-Controlled Analog Data Logging

* Fault and Overvoltage Protection

* Fall-Safe with Power Loses (No Latchup)

* Beak-Before-Make Switching

* All Channels Off when Power Off

* Internal Data Latches