Performance of UniversalStepdown 3V3 version

This page provides evaluation of RB0005 – UniversalStepdown shown in the photo below:

You can use the step-down regulator with input voltage up to 18 V. Without an active cooling the step-down is able to deliver 3 A continuously on the output. The step-down shows a voltage drop on the output when it is loaded with 4 A continuously. This is probably caused by a high die temperature inside the driver IC which leads to a shift in the internal voltage reference. Once you introduce extra cooling, it can deliver over 4 A continuously. We do not recommend to source more than 4 A continuously as higher currents trigger the internal over-temperature protection leading to a regulator shut-down.

The ripple on the output is less than 100 mV peak-to-peak in the worst case. In loads less than 2 A the output ripple is less than 50 mV.

The voltage drop on the step-down is 420 mV under 100 mA load. When the load increases to 4 A the drop increases to 900 mV.

You can examine our test setup in the bottom of the page.

RB0005 – UniversalStepdown properties

The following tables provides raw data from testing the step-down converter. Please note that the oscilloscope screenshots can differ in voltage per division.

The chip and coil temperature was measured by a K-type thermocoupler after 5 minutes of operation for a 1 minute. In one of the cases the temperature did not rise, therefore, the measurement should reflect conditions during continuous operation.

Parameters for input voltage 14.0 V

Load	Output voltage	Output ripple	Input current	Temperature chip, coil	Output voltage waveform
0.1 A	3.32 V	40 mV	0.03 A	23 °C, 25°C	waveform
0.5 A	3.32 V	40 mV	0.13 A	28 °C, 29°C	waveform
1 A	3.32 V	30 mV	0.26 A	30 °C, 32°C	waveform
2 A	3.32 V	70 mV	0.51 A	36 °C, 39°C	waveform
3 A	3.29 V	100 mV	0.79 A	48 °C, 60°C	waveform
4 A	3.02 V	90 mV	1.01 A	80 °C, 91°C	waveform

Parameters for input voltage 7.4 V

Load	Output voltage	Output ripple	Input current	Temperature chip, coil	Output voltage waveform
0.1 A	3.32 V	40 mV	0.05 A	23 °C, 24°C	waveform
0.5 A	3.32 V	50 mV	0.24 A	27 °C, 28°C	waveform
1 A	3.31 V	50 mV	0.47 A	29 °C, 30°C	waveform
2 A	3.32 V	70 mV	0.96 A	33 °C, 37°C	waveform
3 A	3.32 V	90 mV	1.49 A	43 °C, 52°C	waveform
4 A	3.16 V	90 mV	1.96 A	62 °C, 77°C	waveform

Parameters for input voltage 4.2 V

Load	Output voltage	Output ripple	Input current	Temperature chip, coil	Output voltage waveform
0.1 A	3.31 V	40 mV	0.08 A	25 °C, 25°C	waveform
0.5 A	3.31 V	30 mV	0.4 A	26 °C, 26°C	waveform
1 A	3.31 V	30 mV	0.81 A	26 °C, 27°C	waveform
2 A	3.32 V	50 mV	1.69 A	29 °C, 34°C	waveform
3 A	3.33 V	70 mV	2.67 A	41 °C, 51°C	waveform
4 A	3.13 V	70 mV	3.56 A	66 °C, 78°C	waveform