RT9953

5

DS9953-02 April 2011

www.richtek.com

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

LX1

Switch Node of CH1. High impedance in shutdown mode.

2

PVDD1

Power Input of CH1.

3

EN3

Enable Control Input of CH3.

4

FB4

Feedback Input of CH4. High impedance in shutdown mode.

5

SS

Soft-Start Control Input.

6

PVDD4

Power Input of CH4.

7

LX4

Switch Node of CH7. High impedance in shutdown mode.

8

EN5

Enable Control Input of CH5.

9

VOUT5

Output Voltage of CH5.

10

FB5

Feedback Input of CH5. High impedance in shutdown mode.

11

PVDD5

Power Input of CH5.

12

LX3

Switch Node of CH3. High impedance in shutdown mode.

13

PVDD3

Power Input of CH3.

14

EN2

Enable Control Input of CH2.

15

FB3

Feedback Input of CH3. High impedance in shutdown mode.

16

VDDM

Analog Power Input.

17

PVDD2

Power Input of CH2.

18

LX2

Switch Node of CH2. High impedance in shutdown mode.

19

SEL

Selection Input for CH2 step-up or step-down operation mode. Logic state can

not be changed during operation.

20

EN4

Enable Control Input of CH4.

21

FB2

Feedback Input of CH2. High impedance in shutdown mode.

22

FB1

Feedback Input of CH1. High impedance in shutdown mode.

23,

25 (Exposed Pad)

GND

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

GND for maximum thermal dissipation.

24

EN1

Enable Control Input of CH1.