A 4-layer PCB with a solid ground plane and a separate power plane is recommended. The device should be placed near the battery, and the power traces should be wide and short to minimize resistance and inductance.
The sense resistor value depends on the maximum current and voltage of your application. A general rule of thumb is to choose a sense resistor value that results in a voltage drop of around 50-100 mV at the maximum current. You can use the formula Rsense = 0.05V / Imax to estimate the sense resistor value.
The EN pin is an active-high enable input that allows you to turn the device on and off. When EN is high, the device is enabled, and when EN is low, the device is disabled. You can use the EN pin to implement power-saving modes or to turn off the device during shutdown.
The BQ29311PWR has a built-in overcurrent protection feature that limits the output current to a safe value. You can adjust the overcurrent threshold by selecting the right sense resistor value. When an overcurrent condition is detected, the device will limit the output current to prevent damage.
A 10-22 uF ceramic capacitor is recommended for the input capacitor. The capacitor should be placed as close to the VIN pin as possible to filter out noise and ripple.
BQ29311PWR datasheet
by Texas Instruments
