The MAX4533 quad, single-pole/double-throw (SPDT), fault-protected analog switch is pin-compatible with the industry-standard MAX333 and MAX333A. The MAX4533 features fault-protected inputs and rail-to-rail signal handling. The normally open (NO_ ) and normally closed (NC_ ) terminals are protected from overvoltage faults up to ±25V with power on and up to ±40V with power off. During a fault condition, NO_ and NC_ become high impedance with only nanoamperes of leakage current flowing to the source. In addition, the output (COM_) clamps to the appropriate polarity supply rail and provides up to ±10mA of load current. This ensures unambiguous rail-to-rail outputs when a fault occurs.The MAX4533 operates from dual ±4.5V to ±18V power supplies or a single +9V to +36V supply. All digital inputs have +0.8V and +2.4V logic thresholds, ensuring both TTL and CMOS logic compatibility when using ±15V supplies or a +12V supply. On-resistance is 175Ω max and is matched between switches to 10Ω max. The off-leakage current is only 0.5nA at TA= +25°C and 10nA at TA= +85°C.ApplicationsAvionics and Military SystemsCommunication SystemsData AcquisitionIndustrial and Process ControlPortable InstrumentationRedundant/Backup SystemsTest Equipment