April 2010 Doc ID 13632 Rev 4 1/18
18
ST1S09
2 A, 1.5 MHz PWM step-down switching regulator
with synchronous rectification
Features
■ 1.5 MHz fixed frequency PWM with current
control mode
■ 2 A output current capability
■ Typical efficiency: > 90%
■ 2 % DC output voltage tolerance
■ Two versions available: power good or inhibit
■ Integrated output over-voltage protection
■ Non switching quiescent current: (typ) 1.5 mA
over temperature range
■ R
DSON
(typ) 100 mΩ
■ Utilizes tiny capacitors and inductors
■ Operating junction temp. -30 °C to 125 °C
■ Available in DFN6 (3 x 3 mm) exposed pad
Description
The ST1S09 is a step-down DC-DC converter
optimized for powering low output voltage
applications. It supplies a current in excess of 2 A
over an input voltage range from 2.7 V to 6 V.
A high PWM switching frequency (1.5 MHz)
allows the use of tiny surface-mount components.
Moreover, since the required synchronous
rectifier is integrated, the number of the external
components is reduced to minimum: a resistor
divider, an inductor and two capacitors. The
Power Good function continuously monitors the
output voltage. An open drain Power Good flag is
released when the output voltage is within
regulation. In addition, 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 thermally protected and
the output current limited to prevent damages due
to accidental short circuit. The ST1S09 is
available in the DFN6 (3 x 3 mm) package.
DFN6 (3 x 3 mm)
Table 1. Device summary
Order codes Package
ST1S09PUR DFN6D (3 x 3 mm)
ST1S09APUR
(1)
DFN6D (3 x 3 mm)
ST1S09IPUR DFN6D (3 x 3 mm)
1. Available on request.
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