Analog Multiplexer Single 8:1 16-Pin CDIP

The HI-508A are 8 channel single-ended (1 of 8) multiplexers with fault protection. Using a series N-channel, P-channel, N-channel structure, these multiplexers provide significantly improved fault protection. If the power supplies to the fault-protected multiplexer are inadvertently turned off while input voltages are still applied, all channels in the multiplexer are turned off, and only a few nanoamperes of leakage current will flow into the inputs. This protects not only the multiplexer and the circuitry driven by the multiplexer, but also protects the sensors or signal sources which drive the multiplexer. The HI-508A N-channel, P-channel, N-channel protection structure has two significant advantages over the simple current limiting protection scheme of the first generation fault protected multiplexers. First, the protection scheme limits fault currents to nanoamp leakage values rather than many milliamperes. This prevents damage to sensors or other sensitive signal sources. Second, the fault-protected multiplexers can withstand a continuous ±35V overvoltage, unlike the first generation which has a continuous overvoltage limitation of about ±10V imposed by power dissipation considerations. All digital inputs have logic thresholds of 0.8V and 2.4V, ensuring both TTL and CMOS compatibility without requiring pull-up resistors. Break-before make operation is guaranteed. Power supply currents have been reduced and typical power dissipation is less than 2 milliwatts.

• Improved 2nd Source
• All Switches Off with Power Supplies Off
• On Channel Turns OFF if Overvoltage Occurs
• Only Nanoamperes of Input Current under All Fault Conditions
• Latchup-proof Construction
• Operates from ±4.5 to ±18V Supplies
• All Digital Inputs are TTL and CMOS Compatible
• 8 channel single-ended (1 of 8) multiplexers with fault protection