A good PCB layout for optimal thermal performance involves placing the device near a thermal pad or a heat sink, and ensuring good thermal conductivity between the device and the heat sink. A 4-layer PCB with a solid ground plane and a thermal relief pattern can also help to dissipate heat efficiently.
To ensure accurate temperature measurement, it's essential to calibrate the device, use a high-accuracy voltage reference, and minimize noise and interference in the circuit. Additionally, the device should be placed close to the thermal source being measured, and the thermal interface material should be optimized for good thermal conductivity.
The recommended power-up sequence for the LM94021B involves applying the power supply voltage (VCC) before the input voltage (VIN). This ensures that the internal voltage regulator is fully powered up before the input voltage is applied, which helps to prevent latch-up and ensures reliable operation.
The output voltage tolerance of the LM94021B can be handled by using a voltage regulator with a tighter output voltage tolerance, such as ±1% or ±2%. Additionally, the output voltage can be trimmed using an external resistor divider network or a voltage adjustment pin, if available.
The maximum allowed power dissipation for the LM94021B depends on the package type and the ambient temperature. For the QFN package, the maximum power dissipation is typically around 1.4W at an ambient temperature of 25°C. However, this value can be derated based on the actual operating conditions and the thermal resistance of the package.
LM94021BIMGX/NOPB datasheet
by Texas Instruments
