The VM pin should be bypassed to GND using low-ESR ceramic bypass capacitor with a recommended value of 68 nF rated for VM. The capacitor should be placed as close to the VM pin as possible with a thick trace or ground plane connection to the device GND pin.

Bypass the VDD pin to ground with a low-ESR ceramic capacitor. A value of 100 nF rated for 6.3 V is recommended. Place this bypassing capacitor as close to the pin as possible.

In general, inductance between the power supply pins and decoupling capacitors must be avoided.

Connect series resistors between IN0, IN1, nSLEEP, nSCS, SCLK, SDI, SDO and VDD pins of the device and corresponding pins of the microcontroller. The recommended values of the resistors are shown in Section 7.3.

The thermal PAD of the package must be connected to system ground.

• It is recommended to use a big unbroken single ground plane for the whole system / board. The ground plane can be made at bottom PCB layer.

• In order to minimize the impedance and inductance, the traces from ground pins should be as short and wide as possible, before connecting to bottom layer ground plane through vias.

• Multiple vias are suggested to reduce the impedance.

• Try to clear the space around the device as much as possible especially at bottom PCB layer to improve the heat spreading.

• Single or multiple internal ground planes connected to the thermal PAD will also help spreading the heat and reduce the thermal resistance.