RT8295B Ver la hoja de datos (PDF) - Richtek Technology
Número de pieza
componentes Descripción
Fabricante
RT8295B Datasheet PDF : 14 Pages
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RT8295B
Typical Application Circuit
VIN
4.5V to 23V
CSS
0.1µF
1C0INµF
2 VIN
BOOT 1
RT8295B
SW 3
CBOOT L
100nF 3.6µH
REN 100k
7 EN
R1
75k
8 SS
FB 5
4, 9 (Exposed Pad)
GND
COMP 6
CC
0.82nF
RC
32k
R2
24k
VOUT
3.3V/2A
COUT
22µF x 2
VOUT (V)
8
5
3.3
2.5
1.5
1.2
1
Table 1. Recommended Component Selection
R1 (kΩ) R2 (kΩ) RC (kΩ) CC (nF) L (µH)
27
3
75
0.82
10
62
11.8
47
0.82
6.8
75
24
32
0.82
3.6
25.5
12
25.5
0.82
3.6
10.5
12
15
0.82
2
12
24
12
0.82
2
3
12
10
0.82
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.
Pin Name
Pin Function
1
BOOT
Bootstrap for High Side Gate Driver. Connect a 0.1µF or greater ceramic
capacitor from BOOT to SW pins.
2
VIN
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
5
FB
6
COMP
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
the output of the converter to regulate to the desired value via an internal
resistive voltage divider. For an adjustable output, an external resistive
voltage divider is connected to this pin.
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.
Chip Enable (Active High). A logic-low forces the RT8295B 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
2
DS8295B-03 March 2011
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