ATSAMB11XR datasheet(68/87 Pages) MICROCHIP

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Dedicate one layer as a ground plane, preferably the second layer from the top. Make sure that this

ground plane does not get broken up by routes. Power can route on all layers except the ground layer.

Power supply routes should be heavy copper fill planes to ensure the lowest possible inductance. The

power pins of the ATSAMB11-XR2100A should have a via directly to the power plane as close to the pin

as possible. Decoupling capacitors should have a via right next to the capacitor pin and this via should go

directly down to the power plane – that is to say, the capacitor should not route to the power plane

through a long trace. The ground side of the decoupling capacitor should have a via right next to the pad

which goes directly down to the ground plane. Each decoupling capacitor should have its own via directly

to the ground plane and directly to the power plane right next to the pad. The decoupling capacitors

should be placed as close to the pin that it is filtering as possible.

13.1.2

Antenna

When designing the ATSAMB11-XR2100A, it is important to pay attention to the following

recommendations for antenna placement:

Make sure to choose an antenna that covers the proper frequency band; 2.400 GHz to 2.500 GHz.

Assure that the antenna is designed matched to 50 Ohm input impedance.

Talk to the antenna vendor and make sure it is understood that the full frequency range must be

covered by the antenna.

Be sure to follow the antenna vendors best practice layout recommendations, while placing the

antenna in the customer PCB design.

The customer PCB pad that the antenna is connected to must be properly designed for 50 Ohm

impedance.

Make sure that the trace from the RF pin on the ATSAMB11-XR2100A to the antenna matching

circuitry has a 50 Ohm impedance.

Do not enclose the antenna within a metal shield.

Keep any components that may radiate noise or signals within the 2.4 GHz to 2.5 GHz frequency

band far away from the antenna and RF traces or better yet, shield the noisy components. Any

noise radiated from the customer PCB in this frequency band will degrade the sensitivity of the

ATSAMB11-XR2100A device.

13.2

SWD Interface

For programming and/or debugging the ATSAMB11XR/ZR, the device must be connected using the

Serial Wire Debug (SWD) interface. Currently, the SWD interface is supported by Microchip programmers

and debuggers SAM-ICE and ATMEL-ICE.

For ATMEL-ICE, which supports Cortex Debug Connector (10-pin) interface, the signals must be

connected, as shown in Figure 13-2 with details described in Table 13-1.

ATSAMB11XR/ZR

Datasheet Preliminary

DS70005342A-page 68

ATSAMB11XR Datasheet(PDF) 68 Page - Microchip Technology