Fault-Protected, High-Voltage Signal-Line Protectors

The MAX4506/MAX4507 multiple, two-terminal signal-line protectors are pin-compatible with the industry-standard MAX366/MAX367. These new circuit protectors feature fault-protected inputs and rail-to-rail signal handling capability. The input pins are protected from overvoltage faults up to ±36V with power on or ±40V with power off. During a fault condition, the input terminal becomes an open circuit and only nanoamperes of leakage current flow from the source; but the switch output (OUT) furnishes typically 19mA from the appropriate polarity supply to the load. This ensures unambiguous rail-to-rail outputs when a fault begins and ends.

The MAX4506 contains three independent protectors while the MAX4507 contains eight independent protectors. They can protect both unipolar and bipolar analog signals using either unipolar (+9V to +36V) or bipolar (±8V to ±18V) power supplies.

These devices have no logic control inputs; the protectors are designed to be always-on when the supplies are on. On-resistance is 100Ω max and matched within 7Ω , and on-leakage is less than 0.5nA at TA = +25°C. The MAX4506 is available in 8-pin SO/DIP packages. The MAX4507 is available in 20-pin SSOP and 18-pin SO/DIP packages.

Applications

* Automated Test Equipment (ATE) * Data Acquisition Systems * Hot-Insertion Boards/Systems * Process Control Systems * Redundant/Backup Systems * Sensitive Instruments

* Overvoltage Protection * ±40V with Power Off

* ±36V with Power On

* Open Signal Paths with Power Off

* Output Clamps to Either Rail with an Input Overvoltage

* Any On Channel Output is Not Affected by an Overvoltage to Any Other Channel

* 100Ω max On-Resistance

* 10ns Overvoltage Turn-On Delay

* No Latchup During Power Sequencing

* Rail-to-Rail Signal Handling

* 500Ω Output Clamp Resistance During Overvoltage