M ▁band ▁So C ▁series , ▁the ▁n R F 5 2 ▁which ▁incorpor ate ▁the ▁AR M ▁Cor tex - M 4 ▁as ▁their ▁core . ▁In ▁January ▁ 2 0 1 8 , ▁Nord ic ▁Sem icon duct or ▁introduced ▁and ▁started ▁sampling ▁to ▁selected ▁lead ▁customers ▁their ▁first ▁L TE ▁So C , ▁the ▁n R F 9 1 ▁series . In ▁November ▁ 2 0 1 9 , ▁Nord ic ▁Sem icon duct or ▁introduced ▁and ▁started ▁sampling ▁to ▁selected ▁lead ▁customers ▁their ▁new ▁flags hip ▁So C ▁containing ▁dual - core ▁AR M ▁Cor tex - M 3 3 ▁process ors ▁and ▁a ▁multi - protocol ▁radio ▁stack ▁( N FC / B LE / B LE ▁mesh / Z ig be e / Thread / oth ers ), ▁the ▁n R F 5 3 ▁series . ▁ ▁Product s ▁ ▁Nord ic ▁Sem icon duct or ▁designs ▁and ▁produces ▁So C ▁and ▁connect ivity ▁solutions ▁primarily ▁for ▁the ▁IS M ▁bands ▁at ▁ 2 . 4   G Hz ▁and ▁ 8 6 8 / 9 1 5   M Hz ▁bands . ▁Current ▁products ▁include ▁So C s ▁incorpor ating ▁the ▁AR M ▁Cor tex - M 0 , ▁AR M ▁Cor tex - M 4 ▁and ▁AR M ▁Cor tex - M 3 3 ▁micro controller ▁cores . ▁ ▁Some ▁of ▁their ▁most ▁popular ▁products ▁are ▁the ▁n R F 2 4 L 0 1 + ▁and ▁the ▁n R F 2 4 LE 1