LM89CIMX/NOPB Frequently Asked Questions (FAQs)

• What is the recommended PCB layout for optimal thermal performance?
  Texas Instruments recommends a 2-layer or 4-layer PCB with a solid ground plane on the bottom layer and a thermal relief pattern on the top layer to ensure good thermal conductivity. Additionally, keeping the thermal pad connected to the ground plane can help to reduce thermal resistance.
• How do I ensure accurate temperature measurement with the LM89?
  To ensure accurate temperature measurement, it's essential to follow proper PCB layout and thermal design guidelines. Additionally, calibrate the device by measuring the temperature of a known reference point, such as an ice bath or a temperature-controlled oven, and adjusting the offset voltage accordingly.
• What is the maximum allowed voltage on the VCC pin?
  Although the datasheet specifies a maximum operating voltage of 5.5V, it's recommended to limit the voltage on the VCC pin to 5V to ensure reliable operation and prevent damage to the device.
• Can I use the LM89 with a 3.3V power supply?
  Yes, the LM89 can operate with a 3.3V power supply, but the output voltage range will be limited to 0.25V to 2.75V. Additionally, the device's accuracy and linearity may be affected at lower supply voltages.
• How do I handle the thermal shutdown feature in my design?
  The thermal shutdown feature is designed to protect the device from overheating. When the device exceeds the thermal shutdown threshold (typically 150°C), it will shut down and reset when the temperature drops below the thermal reset threshold (typically 140°C). In your design, ensure that the device has sufficient thermal relief and that the thermal shutdown feature is properly handled in your system's fault detection and recovery mechanisms.