SS6620 Datasheet, PDF (1/12 Pages) Silicon Standard Corp. – High Efficiency Synchronous Step-Up DC/DC Converter

SS6620/21/2
High Efficiency Synchronous Step-Up DC/DC Converter
n ^FEATURES
l High efficiency of 93% (VIN=2.4V, VOUT=3.3V,
I_OUT=200mA).
l Quiescent supply current of 20µA.
l Power-saving shutdown mode (0.1µA typical).
l Internal synchronous rectifier (no external diode )
l Selectable current limit for reduced ripple
(SS6622).
l Low noise, anti-ringing feature (SS6622)
l On-chip low-battery detector.
l Low-battery hysteresis
n ^APPLICATIONS
l Palmtop & notebook computers.
l PDAs
l Wireless phones
l Pocket organizers.
l Cameras.
l 1 to 2-cell hand-held devices
n ^DESCRIPTION
The SS6620/21/22 are high-efficiency step-
up DC/DC converters, with start-up voltage as
low as 0.8V and operating with an input voltage
down to 0.7V. Consuming only 20µA of quies-
cent current, these devices offer a built-in syn-
chronous rectifier that reduces size and cost by
eliminating the need for an external Schottky
diode, improving overall efficiency by minimiz-
ing losses.
The switching frequency depends on the load
and the input voltage and can range up to
500KHz. The peak current of the internal switch
is fixed at 0.8A (SS6620), at 0.45A
(SS6621), or is selectable (SS6622) for
design flexibility. Ripple does not exceed the
product of the switch current limit and the filter
capacitor equivalent-series-resistance (ESR).
The SS6622 also features a circuit that
eliminates noise caused by inductor ringing.
n ^{TYPICAL APPLICATION CIRCUIT}
V_IN
+
100µF
ON
OFF
Low-Battery
Detect In
SHDN
SS6620
SS6621
SS6622
LBI
LX
OUT
LBO
REF _LBFOB GNDFB
0.1µF
22µH
Output 3.3V, or
Adj. (1.8V to 4.0V)
+ ^{up to 300mA}
220µF
Low-Battery
Detect Out
Rev.2.01 6/06/2003
www.SiliconStandard.com
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