4N35 - onsemi

4N35 Frequently Asked Questions (FAQs)

• What is the maximum allowable voltage across the input pins?
  The maximum allowable voltage across the input pins is 5V to 30V, but it's recommended to keep it below 20V for reliable operation.
• How do I ensure the 4N35 is fully turned off when the input is low?
  To ensure the 4N35 is fully turned off, the input voltage should be less than 0.5V and the input current should be less than 1mA. Additionally, a pull-down resistor can be used to discharge the input capacitance.
• What is the minimum input current required to turn on the output?
  The minimum input current required to turn on the output is typically around 1mA to 5mA, depending on the specific application and desired output current. However, it's recommended to use a higher input current (e.g., 10mA) for reliable operation.
• Can I use the 4N35 for high-frequency applications?
  The 4N35 is not suitable for high-frequency applications (>10kHz) due to its limited bandwidth and rise/fall times. For high-frequency applications, consider using a faster optocoupler like the 6N137 or 7N137.
• How do I handle the output current when the input is high?
  When the input is high, the output current can be limited using a current-limiting resistor or a transistor switch. The output current should not exceed the maximum rating of 50mA to prevent damage to the device.