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C5
1
U1
INPUT
4.75V to 21V
C1
10uF/35V
CERAMIC x2
OFF ON
2
7
8
C4
0.1uF
4
IN
EN
SS
GND
FB
COMP
5
6
C6
R3
5.6KΩ
10nF
BS
L1
D1
15uH
R1
25.8KΩ 1%
C2
OUTPUT
3.3V/2A
SW
3
B340A
(Optional)
C3
8.2nF
R2
10KΩ 1%
22uF/6.3V
CERAMIC x2
RS6508‐ADS
Pin Assignments
MSOP‐10(EP)
SOP‐8
PACKAGE
1
PIN
‐
SYMBOL
NC
DESCRIPTION
2
1
BS
3
4
MSOP‐10(EP)
/
SOP‐8
‐
2
NC
IN
5
6,11
7
3
4
5
SW
GND
FB
8
6
COMP
9
10
7
8
EN
SS
No Connect.
Bootstrap. This capacitor (C5) is needed to drive the power switch’s gate
above the supply voltage. It is connected between the SW and BS pins to
form a floating supply across the power switch driver. The voltage across
C5 is about 5V and is supplied by the internal +5V supply when the SW pin
voltage is low.
No Connect.
Supply Voltage. The RS6515 operates from a 4.75V to 20V unregulated
input. C1 is needed to prevent large voltage spikes from appearing at the
input.
Power Switching Output. SW is the switching node that supplies power to
the output. Connect the output LC filter from SW to the output load. Note
that a capacitor is required from SW to BS to power the high‐side switch.
Ground.
Feedback Input. FB senses the output voltage and regulates it. Drive FB
with a resistive voltage divider from the output voltage to ground. The
feedback threshold is 0.92V. See Setting the Output Voltage.
Compensation Node. COMP is used to compensate the regulation control
loop. Connect a series RC network from COMP to GND. In some cases, an
additional capacitor from COMP to GND is required. See Compensation.
Enable Input. EN is a digital input that turns the regulator on or off. Drive
EN high to turn on the regulator, drive it low to turn it off. For automatic
startup, leave EN unconnected.
Soft‐Start. Connect SS to an external capacitor to program the soft‐start. If
unused, leave it open.
DS‐RS6515‐08
JULY, 2010
www.Orister.com
ORISTER [ ORISTER CORPORATION ]
