diff --git a/tests/drivers/adc/adc_api/boards/nrf54h20dk_nrf54h20_cpuapp.overlay b/tests/drivers/adc/adc_api/boards/nrf54h20dk_nrf54h20_cpuapp.overlay
index 789d1efdf05..d9c1f965add 100644
--- a/tests/drivers/adc/adc_api/boards/nrf54h20dk_nrf54h20_cpuapp.overlay
+++ b/tests/drivers/adc/adc_api/boards/nrf54h20dk_nrf54h20_cpuapp.overlay
@@ -6,7 +6,7 @@
 
 / {
 	zephyr,user {
-		io-channels = <&adc 0>, <&adc 2>;
+		io-channels = <&adc 0>, <&adc 1>, <&adc 2>;
 	};
 };
 
@@ -23,6 +23,15 @@
 		zephyr,resolution = <10>;
 	};
 
+	channel@1 {
+		reg = <1>;
+		zephyr,gain = "ADC_GAIN_2";
+		zephyr,reference = "ADC_REF_EXTERNAL0";
+		zephyr,acquisition-time = <ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 10)>;
+		zephyr,input-positive = <NRF_SAADC_AIN3>;
+		zephyr,resolution = <10>;
+	};
+
 	channel@2 {
 		reg = <2>;
 		zephyr,gain = "ADC_GAIN_1_2";
diff --git a/tests/drivers/adc/adc_api/boards/nrf54l15pdk_nrf54l15_cpuapp.overlay b/tests/drivers/adc/adc_api/boards/nrf54l15pdk_nrf54l15_cpuapp.overlay
index e10ddc54328..a7252902a0c 100644
--- a/tests/drivers/adc/adc_api/boards/nrf54l15pdk_nrf54l15_cpuapp.overlay
+++ b/tests/drivers/adc/adc_api/boards/nrf54l15pdk_nrf54l15_cpuapp.overlay
@@ -6,7 +6,7 @@
 
 / {
 	zephyr,user {
-		io-channels = <&adc 0>, <&adc 2>;
+		io-channels = <&adc 0>, <&adc 1> , <&adc 2>;
 	};
 };
 
@@ -23,9 +23,18 @@
 		zephyr,resolution = <10>;
 	};
 
+	channel@1 {
+		reg = <1>;
+		zephyr,gain = "ADC_GAIN_1_4";
+		zephyr,reference = "ADC_REF_EXTERNAL0";
+		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;
+		zephyr,input-positive = <NRF_SAADC_AIN4>;
+		zephyr,resolution = <12>;
+	};
+
 	channel@2 {
 		reg = <2>;
-		zephyr,gain = "ADC_GAIN_1";
+		zephyr,gain = "ADC_GAIN_2_5";
 		zephyr,reference = "ADC_REF_INTERNAL";
 		zephyr,acquisition-time = <ADC_ACQ_TIME(ADC_ACQ_TIME_MICROSECONDS, 10)>;
 		zephyr,input-positive = <NRF_SAADC_AIN2>;