RT8283B Просмотр технического описания (PDF) - Richtek Technology
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RT8283B Datasheet PDF : 14 Pages
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RT8283B
Typical Application Circuit
VIN
4.5V to 23V
CSS
0.1µF
CIN
10µF x 2
2 VIN
BOOT 1
RT8283B
SW 3
CBOOT L
100nF 3.6µH
REN 100k
7 EN
R1
75k
8 SS
FB 5
4, Exposed Pad (9)
GND
COMP 6
CC
2.2nF
RC
22k
R2
24k
VOUT
3.3V/3A
COUT
22µF x 2
Recommended Component Selection
VOUT (V)
8
5
3.3
2.5
1.5
1.2
1
R1 (kΩ)
27
62
75
25.5
10.5
12
3
R2 (kΩ)
3
11.8
24
12
12
24
12
RC (kΩ)
51
33
22
16
10
8.2
6.8
CC (nF)
2.2
2.2
2.2
2.2
2.2
2.2
2.2
L (μH)
10
6.8
3.6
3.6
2
2
2
CP
Open
COUT (μF)
22 x 2
22 x 2
22 x 2
22 x 2
22 x 2
22 x 2
22 x 2
Functional Pin Description
Pin No.
1
2
Pin Name
BOOT
VIN
Pin Function
Bootstrap for High Side Gate Driver. Connect a 0.1μF or greater ceramic
capacitor from BOOT to SW pins.
Input Supply Voltage, 4.5V to 23V. Must bypass with a suitably large ceramic
capacitor.
3
SW
Switch Node--Connect this pin to an external L-C filter.
4,
9 (Exposed Pad)
GND
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Feedback Input. This pin is connected to the converter output. It is used to set
5
FB
the output of the converter to regulate to the desired value via an internal
resistive divider. For an adjustable output, an external resistive divider is
connected to this pin.
Compensation Node. COMP is used to compensate the regulation control
6
COMP
loop. Connect a series RC network from COMP to GND. In some cases, an
additional capacitor from COMP to GND is required.
Chip Enable (Active High). A logic low forces the RT8283B into shutdown
7
EN
mode reducing the supply current to less than 3μA. Attach this pin to VIN with
a 100kΩ pull up resistor for automatic startup.
Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor
8
SS
from SS to GND to set the soft-start period. A 0.1μF capacitor sets the
soft-start period to 13.5ms.
www.richtek.com
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DS8283B-01 March 2011
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