This document summarizes the relevant differences when migrating from SAM L21 variant A (SAM L21A) to SAM L21 variant B (SAM L21B).

Variant A devices have only been available as engineering samples and have not been released to production. All devices released to production are variant B devices.

Refer to the SAM L21 datasheet for detailed information on the device. Part naming details can be found in Chapter "Ordering Information" in the datasheet.

Erratas for variant A which are fixed are not discussed in this document, as these are documented in the datasheet.

Characteristics are not discussed in this document.