diff --git a/samples/drivers/adc/adc_dt/boards/sam_v71_xult_samv71q21.overlay b/samples/drivers/adc/adc_dt/boards/sam_v71_xult_samv71q21.overlay
index 950b1f7ee8a..5c078bb73b5 100644
--- a/samples/drivers/adc/adc_dt/boards/sam_v71_xult_samv71q21.overlay
+++ b/samples/drivers/adc/adc_dt/boards/sam_v71_xult_samv71q21.overlay
@@ -18,7 +18,8 @@
 	channel@0 {
 		reg = <0>;
 		zephyr,gain = "ADC_GAIN_1";
-		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,reference = "ADC_REF_EXTERNAL0";
+		zephyr,vref-mv = <3300>;
 		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
 		zephyr,resolution = <12>;
 	};
@@ -26,7 +27,8 @@
 	channel@8 {
 		reg = <8>;
 		zephyr,gain = "ADC_GAIN_1";
-		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,reference = "ADC_REF_EXTERNAL0";
+		zephyr,vref-mv = <3300>;
 		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
 		zephyr,resolution = <12>;
 	};
diff --git a/samples/drivers/adc/adc_sequence/boards/sam_v71_xult_samv71q21.overlay b/samples/drivers/adc/adc_sequence/boards/sam_v71_xult_samv71q21.overlay
index 3da0d7d4c83..19b3d3104d7 100644
--- a/samples/drivers/adc/adc_sequence/boards/sam_v71_xult_samv71q21.overlay
+++ b/samples/drivers/adc/adc_sequence/boards/sam_v71_xult_samv71q21.overlay
@@ -17,14 +17,16 @@
 	channel@0 {
 		reg = <0>;
 		zephyr,gain = "ADC_GAIN_1";
-		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,reference = "ADC_REF_EXTERNAL0";
+		zephyr,vref-mv = <3300>;
 		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
 	};
 
 	channel@8 {
 		reg = <8>;
 		zephyr,gain = "ADC_GAIN_1";
-		zephyr,reference = "ADC_REF_INTERNAL";
+		zephyr,reference = "ADC_REF_EXTERNAL0";
+		zephyr,vref-mv = <3300>;
 		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
 	};
 };