RT8265

2

DS8265-02 March 2011

www.richtek.com

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

BOOT

High Side Gate Drive Boost Input. BOOT supplies the drive for the high side

N-MOSFET switch. Connect a 10nF or greater capacitor from SW to BS to power the

high side switch.

2

VIN

switches. Bypass VIN to GND with a suitable large capacitor to eliminate noise on the

input to the IC.

3

SW

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.

4,

9 (Exposed Pad)

GND

Ground. The exposed pad must be soldered to a large PCB and connected to GND

for maximum power dissipation.

5

FB

Feedback Input. FB senses the output voltage to regulate said voltage. The feedback

reference voltage is 0.8V typically.

6

COMP

Compensation Node. COMP is used to compensate the regulation control loop.

Connect a series RC network from COMP to GND to compensate the regulation

control loop. In some cases, an additional capacitor from COMP to GND is required.

7

EN

Enable Input. EN is a digital input that turns the regulator on or off. Drive EN higher

than 1.4V to turn on the regulator, lower than 0.4V to turn it off. If the EN pin is open, it

will be pulled to high by internal circuit.

8

SS

Soft-Start Control Input. SS controls the soft start period. Connect a capacitor from

SS to GND to set the soft-start period. A 0.1

μF capacitor sets the soft-start period to

10ms.

R1 (k

Ω)

R2(k

Ω)

Cp (pF)

L1 (

μH)

15V

280

16

360

0.1

Open

4.7

10V

180

16

240

0.15

Open

4.7

8V

150

16

200

0.22

Open

4.7

5V

84.5

16

140

0.35

Open

4.7

3.3V

49.9

16

82

0.56

Open

4.7

2.5V

33

16

68

0.68

Open

4.7

1.8V

20

16

49.9

1

Open

4.7

1.2V

8.06

16

24

1.5

33

4.7

1.1V

6.04

16

24

1.5

33

4.7

Table 1. Recommended Component Selection