The VM pin should be bypassed to GND using
low-ESR ceramic bypass capacitor with a
recommended value of 68nF 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 100nF rated for 6.3V
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.
TI recommends to use a big unbroken single ground
plane for the whole system / board. The ground
plane can be made at bottom PCB layer.
To minimize the impedance and inductance, the
traces from ground pins are 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 also helps spreading
the heat and reduce the thermal resistance.