ST1S03A 1.5 A, 1.5 MHz adjustable, with inhibit function step-down switching regulator Features Step-down current mode PWM (1.5 MHz) DC- DC converter 2 % DC output voltage tolerance Internal soft start for start-up current limitation and power on delay of 50-100 s Typical efficiency: > 85 % DFN6D (3x3 mm) Inhibit function 1.5 A output current capability Not switching quiescent current: max 1.5 mA over temperature range Switch V : max 200 mV I = 750 mA DS SW Uses tiny capacitors and inductors Available in DFN6D 3x3 exposed pad Description The ST1S03A is a step down DC-DC converter optimized for powering low-voltage digital core in HDD applications and, generally, to replace the high current linear solution when the power dissipation may cause an high heating of the application environment. It provides up to 1.5 A over an input voltage range of 3 V to 5.5 V. An high switching frequency (1.5 MHz) allows the use of tiny surface-mount components: as well as the resistor divider to set the output voltage value, only an inductor, a schottky diode and two capacitors are required. Besides, a low output ripple is guaranteed by the current mode PWM topology and by the use of low ESR SMD ceramic capacitors. The device is thermal protected and current limited to prevent damages due to accidental short circuit. The ST1S03A is available in DFN6D (3x3 mm). Table 1. Device summary Order codes Packaging Package ST1S03APUR Tape and reel DFN6D (3x3 mm) ST1S03AIPUR Tape and reel DFN6D (3x3 mm) June 2008 Rev 6 1/14 www.st.com 14ST1S03A Contents 1 Diagram . 3 2 Pin configuration . 4 3 Maximum ratings 5 4 Electrical characteristics . 6 5 Typical application 7 6 Application notes . 8 7 Package mechanical data . 9 8 Revision history 13 2/14