rt8065 Richtek Technology Corporation, rt8065 Datasheet - Page 2

• Manufacturer Part Number: rt8065
• Description: 3a, 2mhz, Synchronous Step-down Converter
• Manufacturer: Richtek Technology Corporation

RT8065
Typical Application Circuit
www.richtek.com
2
Functional Pin Description
9 (Exposed Pad) 9 (Exposed Pad) GND
(Exposed Pad)
V
OUT
SOP-8
3.3
2.5
1.8
1.5
1.2
1
1
2
3
4
5
6
7
8
(V)
Pin No.
2.7V to 5.5V
PGOOD
R1 (kΩ)
WDFN-8L 3x3
Chip Enable
V
75
51
30
21
12
IN
6
Table 1. Recommended Components Selection for f
1
2
3
4
5
6
7
8
R3
100k
R2 (kΩ)
R
COMP
SS
EN
VIN
LX
RT
FB
PGOOD
10µF
C
24
24
24
24
24
24
OSC
Pin Name
IN
4
8
6
3
VIN
PGOOD
RT
EN
RT8065
R
COMP
Error Amplifier Compensation Point. The current comparator
threshold increases with this control voltage. Connect
external compensation elements to this pin to stabilize the
control loop.
Soft-Start Control Input. Connect a capacitor from SS to GND
to set the soft-start period. A 10nF capacitor sets the
soft-start period to 800μs (typ.).
Enable Control Input. Float or connect this pin to logic high
for enable. Connect to GND for disable.
Power Input Supply. Decouple this pin to GND with a
capacitor.
Internal Power MOSFET Switches Output. Connect this pin
to the inductor.
Oscillator Resistor Input. Connect a resistor from this pin to
GND sets the switching frequency. If this pin is floating, the
frequency will be set at 2MHz internally.
Feedback Pin. Receives the feedback voltage from a
resistive divider connected across the output.
Power Good Indicator. This pin is an open drain logic output
that is pulled to ground when the output voltage is not within
±12.5% of regulation point.
Ground Pin. The exposed pad must be soldered to a large
PCB and connected to GND for maximum power dissipation.
COMP
GND
8.2
33
22
15
13
SS
11
LX
FB
(kΩ)
5
7
1
9 (Exposed Pad)
2
R
C
0.1nF
C
COMP
SS
COMP
L
560
560
560
560
560
560
(pF)
C
Pin Function
COMP
SW
= 1MHz
L (μH)
R1
R2
1.5
1.5
1.5
1.5
2
2
DS8065-03 March 2011
C
OUT
V
OUT
C
OUT
22
22
22
22
22
22
(μF)