Optically Coupled Phototransistor: It consists of a gallium arsenide infrared emitting diode (LED) optically coupled to a silicon NPN phototransistor. This optical coupling provides electrical isolation between the input and output circuits.High Isolation Voltage: The 4N37 offers a high isolation voltage, typically 5300 VRMS. Some versions might have different isolation voltages, like 1500 Vrms mentioned in one datasheet. This ensures robust electrical separation and protection for sensitive circuits.Current Transfer Ratio (CTR): It has a minimum CTR of 100% at a forward current of 10mA. This indicates efficient signal transfer from the input LED to the output phototransistor.Base Connection: The phototransistor has a base connection, allowing for external biasing or control.Interfaces with Common Logic Families: It can be used to interface with various logic families like TTL and CMOS.Low Input-Output Coupling Capacitance: It features a coupling capacitance of less than 0.5 pF, which helps in minimizing signal distortion.6-Pin DIP Package: It is housed in a standard 6-pin Dual In-line Package, suitable for through-hole mounting on printed circuit boards.Wide Operating Temperature Range: It operates reliably across a wide temperature range, typically -55°C to +100°C.Safety Agency Approvals: It holds various safety approvals, including UL recognition (E52744), BSI, FIMKO, CSA, VDE, and CQC. It is also RoHS compliant.General Purpose Switching Circuitry: It's suitable for a broad range of general-purpose switching applications.
