RT5771A
Typical Application Circuit
RT5771A
V
IN
C
IN
10µF
R3
100k
PGOOD
Chip Enable
C1
1µF
FB 1
9
PGOOD
GND
R2
8.2k
4, 5,
11 (Exposed Pad)
3 VIN
2 VCC
R1
6.2k
C
FF
680pF
SW
6, 7
L
1.5µH
C
OUT
22µF x 2
V
OUT
1.05V
10 EN
Table 1. Recommended Component Selection
V
OUT
(V)
3.3
2.5
1.8
1.5
1.2
1.05
1.05
1
R1 (k)
37
26
16.5
12.3
8.2
6.2
6.2
5.6
R2 (k)
8.2
8.2
8.2
8.2
8.2
8.2
8.2
8.2
C
FF
(pF)
430
430
510
560
620
680
6800
680
L (H)
2
2
1.5
1.5
1.5
1.5
1.5
1.5
C
OUT
(F)
22 x 2
22 x 2
22 x 2
22 x 2
22 x 2
22 x 2
22 x 3
22 x 2
Functional Pin Description
Pin No.
1
2
3
4, 5,
11 (Exposed Pad)
6, 7
8
9
10
Pin Name
FB
VCC
VIN
GND
SW
NC
PGOOD
EN
Pin Function
Feedback input. This pin receives the feedback voltage from a resistive
voltage divider connected across the output.
Supply voltage input. Decouple this pin to GND with at least 1F ceramic cap.
Power input. Decouple this pin to GND with at least 10F ceramic cap.
Ground. The exposed pad must be soldered to a large PCB and connected to
GND for maximum power dissipation.
Switch node. Connect this pin to the inductor.
No internal connection.
Power good indicator. This pin is an open drain logic output. The PGOOD will
be pulled to ground when the output voltage is less than 90% of the target
output voltage.
Enable control input. Pull high the EN pin to turn on the converter.
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
2
DS5771A-02 June 2019
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
