L6928_11 Datasheet, PDF (1/16 Pages) STMicroelectronics – High efficiency monolithic synchronous step down regulator

L6928
High efficiency monolithic synchronous step down regulator
Features
■ 2 V to 5.5 V battery input range
■ High efficiency: up to 95%
■ Internal synchronous switch
■ No external Schottky required
■ Extremely low quiescent current
■ 1 µA max shutdown supply current
■ 800 mA max output current
■ Adjustable output voltage from 0.6 V
■ Low dropout operation: up to 100% duty cycle
■ Selectable low noise/low consumption mode at
light load
■ Power Good signal
■ ± 1% output voltage accuracy
■ Current-mode control
■ 1.4 MHz switching frequency
■ Externally synchronizable from 1 MHz to 2
MHz
■ OVP
■ Short-circuit protection
Applications
■ Battery-powered equipment
■ Portable instruments
■ Cellular phones
■ PDAs and hand held terminals
MSOP8
VFQFPN8
(3x3x1.0 mm)
■ DSC
■ GPS
Description
The device is DC-DC monolithic regulator
specifically designed to provide extremely high
efficiency. L6928 supply voltage can be as low as
2 V allowing its use in single Li-Ion cell supplied
applications. Output voltage can be selected by
an external divider down to 0.6 V. Duty cycle can
saturate to 100% allowing low dropout operation.
The device is based on a 1.4 MHz fixed
frequency, current mode architecture. Low
consumption mode operation can be selected at
light load conditions, allowing switching losses to
be reduced. L6928 is externally synchronizable
with a clock which makes it useful in noise
sensitive applications. Other features like Power
Good, overvoltage protection, short-circuit
protection and thermal shutdown (150 °C) are
also present.
Figure 1.
Application test circuit
V_IN=2V to 5.5V
C1
10μF
6.3V
SYNC
7
V_CC
6
RUN
1
2
COMP
D01IN1528
C2
220pF
L 4.7μH
5
LX
R3
500K
8
PGOOD
3
4
VFB
GND
R2
200K
R1
100K
V_OUT=1.8V
C4
10μF
6.3V
April 2011
Doc ID 11051 Rev 6
1/16
www.st.com
16