LM139FK datasheet by Texas Instruments

LM139FK Frequently Asked Questions (FAQs)

• What is the maximum voltage that can be applied to the input pins?
  The maximum voltage that can be applied to the input pins is the supply voltage (VCC) + 0.3V. Exceeding this voltage can cause damage to the device.
• How do I ensure that the comparator output is not oscillating?
  To prevent oscillation, ensure that the output is properly terminated, and the input signals are clean and free of noise. Also, consider adding hysteresis to the comparator by connecting a small resistor and capacitor between the output and the non-inverting input.
• What is the minimum input voltage difference required for the comparator to switch?
  The minimum input voltage difference required for the comparator to switch is typically around 1-2 mV, but this can vary depending on the specific application and noise conditions.
• Can I use the LM139FK as an amplifier?
  No, the LM139FK is a comparator, not an amplifier. It is designed to provide a digital output based on the comparison of two input signals, not to amplify a signal.
• How do I choose the right pull-up resistor value for the output?
  The pull-up resistor value depends on the specific application and the load connected to the output. A general rule of thumb is to choose a value between 1 kΩ and 10 kΩ. A higher value reduces power consumption but increases the rise time of the output signal.