TMP300: TMP300 drive FET

user3300657,

  There are two outputs on the TMP300. One of them is the Vtemp. This is an analog output with high impedance and typically used to feed an amplifier or other high impedance input.  This pin supplies an analog voltage proportional to the temperature and is not recommended to drive a switch.

  The second output is the /OUT pin. This is an open drain output and will switch low when the temperature threshold is met. This pin requires a pull-up resistor to pull the output up to the V+ rail. Because it is a digital open drain output, it can only sink up to 5mA of current. Select a pull up resistor that will limit the current to the /OUT pin to 5mA or less based on the V+ voltage. Example: if the V+ voltage is 5Vdc then a 1K resistor will limit the current to 0.005A. Adjust the resistor value as needed to limit the current for your V+.

  Next, because the /OUT pin is high when the temperature is below the threshold, you will need to use a P-CH Mosfet or add another Mosfet to invert the polarity of an N-CH Mosfet. The inverting stage can be set to drive higher currents to reduce the rise time of the Mosfet gate. If this is a simple switch then higher currents may not be required.

  I hope this answers your question.

Hi, Gordon

Thank you for the answer.