Thermal design

nRF9151 Hardware Design Guidelines

Good thermal design on the application board is essential for maximizing the performance and battery life of nRF9151. Poor thermal design causes nRF9151's built-in thermal protection to trigger more easily, preventing nRF9151 from transmitting and receiving Long-Term Evolution (LTE), Global Navigation Satellite System (GNSS), and DECT NR+ data.

A summary of the thermal characteristics of nRF9151 is shown in the following table.

Table 1. Thermal characteristics of nRF9151
Parameter Value
Maximum average power consumption 1300 mW
Maximum heat power dissipation 1050 mW
Maximum operating temperature 85°C
RThetaJA (Module-to-Ambient) 25.5°C/W
RThetaJB (Module-to-Board) 8.0°C/W
RThetaJC (Module-to-Case) 6.6°C/W
Maximum allowed Tc (Module case temperature) 85°C
Maximum Allowed Tj (Worst case of module components) 85°C
Note: The thermal characteristics are measured at 3.7 V and 25°C with a 50 Ω load in still air conditions. The measurements use a module mounted on a 74x54x1.2 mm 6-layer PCB with high copper coverage on all metal layers.
Note: The RF PA main thermal relief is through the large GND pin 108 at the bottom of nRF9151. Minimize the thermal resistance to the system board.