1.5A / 3.3V step-down DC-DC converter demonstration board
This document describes the STEVAL-ISA047V2, a demonstration board featuring a 1.5 A/3.3 V step-down DC-DC converter. The board is based on the ST1S03A, an adjustable current mode PWM step-down DC-DC converter with an internal 1.5 A power switch packaged in a 6-lead DFN 3x3 mm.
The converter utilizes a constant frequency, current mode, PWM architecture, resulting in low and predictable output ripple with ceramic capacitors. It features an internal soft-start for start-up current limitation and a power-on delay of 50-100 us. To maximize efficiency with light loads, the regulator automatically reduces the switching frequency when the output load drops below 250 mA.
| Output current capability | 1.5 A |
|---|---|
| Output voltage tolerance | 2% |
| Switching frequency | 1.5 MHz |
| Typical efficiency | > 85% |
| Switching quiescent current | max 1.5 mA |
| Switch Vps | max 200 mV @ Igy = 750 mA |
| Power-on delay | 50-100 us |
| Package | 6-lead DFN 3x3 mm |
The demonstration board is based on the ST1S03A, an adjustable current mode PWM step-down DC-DC converter.
Yes, the regulator reduces the switching frequency automatically when the output load becomes less than 250 mA typically.