data/text/DLP4/900271

TMP411: Sensors forum

Part Number: TMP411 Hello, I want to measure the temperature of some mosfets mounted on a heat sink as accurate as possible. I would send the Temperature to MCU, my Question ist: If I used the Tmp411 with pnp Transistor, I want to connect the ground of Mosfet with the Collector of the pnp transistor so it could have a better heat transfer. But in the datasheet, Figure 11 shows the use of arrow symbol on the Collector of the pnp transistor which is in the Figure is different from ground and is not shown as it is connected to ground of the Chip. So can I make this connection from Collector of PNP to ground? If its not possible, is there another solution to measure the temperature of Mosfet but with a direct connection to the heatsink. I thought it would be better to use a transistor with TO-220 Package so I would mount it directly on the heat sink but in the datasheet it recommends MMBT3906LP so I don't know which transistor would be the best to use with TO-220! Please help and thanks in Advance.

Hi, Connecting the collector of the PNP to ground should be okay as long as there is little ground noise. For BJT recommendations please see the below FAQ post. <secret URL>/support/sensors/f/1023/t/892887?-FAQ-Remote-Temperature-Sensors-What-remote-BJT-Thermal-diode-should-I-use- Thanks, David