SS8028 Datasheet, PDF (8/9 Pages) Silicon Standard Corp. – Micro-Power Step-up DC/DC Converter

minimize the output ripple voltage, but proper
selection of the inductor and the output capacitor also
plays a big role. If a larger inductance value or a
smaller capacitance value is used, the output ripple
voltage will increase because the capacitor will be
slightly overcharged each burst cycle. To reduce the
SS8028
output ripple, increase the output capacitance value,
or add a 10pF feed-forward capacitor in the feedback
network of the SS8028 (see the circuits in the
Typical Applications section). To add this small
inexpensive 10pF capacitor will greatly reduce the
output voltage ripple.
TYPICAL APPLICATION CIRCUITS
Boost Converter
V
IN
2.5V to 4.2V
C1
4.7µF
L1
4.7uH
L1:MURATA LQH3C4R7M24
D1:MOTOROLA MBR0520
D1
VCC
SW
VCC
SW
G5111
SHDN
FB
SHDN
FB
GND
390k
R1
120k
R2
5V
50mA
C2
22µF
V
IN
2.5V to 4.2V
SEPIC Converter
C1
4.7µF
L1
10uH
C3
1uF
1
VCC
SW
SHDN
FB
GND
L1,L2:MURATA LQH3C100K24
D1:MOTOROLA MBR0520
D1
L2
10µH
470k
R1
270k
R2
3.3V
60mA
C2
22µF
VBAT
2.5V~5.5V
C1
4.7µF
ON/OFF Control
L1
10µH/0.5A
D1
VCC
MBR0520
SW
SS8028
SHDN
FB
C2
1µF
D2(Optional)
18V
GND
White LED Driver
VBIAS(+3.3V)
R3
308k_1%
PWM Dim
R4
660k_1%
PWM Dimming Control
VH=3.3V
VL=0V
Freq=160~240Hz
R2
120k_1%
R1
30_1%
Dimming Ratio>50:1
Drive 2~4 White LEDs
Rev.2.02 12/06/2003
www.SiliconStandard.com
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