RT9246

1

DS9246-06

March 2007

www.richtek.com

Multi-Phase PWM Controller for CPU Core Power Supply

Ordering Information

General Description

The RT9246 is a multi-phase buck DC/DC controller

integrated with all control functions for GHz CPU VRM.

operating in interleaved phase set automatically. The multi-

phase architecture provides high output current while

maintaining low power dissipation on power devices and

low stress on input and output capacitors. The high

equivalent operating frequency also reduces the

component dimension and the output voltage ripple in load

transient.

RT9246 controls both voltage and current loops to achieve

good regulation, response & power stage thermal balance.

builds precise load line for strict VRM DC & transient

specification and also ensures thermal balance of different

power stages. The settings of current sense, droop tuning,

independent to compensation circuit of voltage loop. The

feature greatly facilitates the flexibility of CPU power supply

design and tuning.

The DAC output of RT9246 supports K8 CPU by 5-bit VID

and over-voltage protection. Soft-start, over-current

protection and programmable under-voltage lockout are

also provided to assure the safety of microprocessor and

power system.

Features

Multi-Phase Power Conversion with Automatic

Phase Selection

K8 DAC Output with Active Droop Compensation

for Fast Load Transient

Sense

Hiccup Mode Over-Current Protection

Programmable Switching Frequency (50kHz to

400kHz per Phase), Under-Voltage Lockout and

Soft-Start

High Ripple Frequency Times Channel Number

RoHS Compliant and 100% Lead (Pb)-Free

Applications

Regulator

Low Output Voltage, High Current DC-DC Converters

Voltage Regulator Modules

Pin Configurations

(TOP VIEW)

TSSOP-28

VID4

VID3

VID1

VID0

ISN1

PWM3

PWM2

VCC

SS2

SGND

ISP2

ISP1

PWM1

ISP3

COMP

PGOOD

GND

ISN23

DVD

SS

VDIF

ADJ

RT

VOSS

IMAX

VSEN

VID2

FB

6

7

8

17

18

19

9

10

11

15

16

12

13

14

4

5

20

21

22

2

3

23

24

25

26

27

28

Note :

RichTek Pb-free and Green products are :

RoHS compliant and compatible with the current require-

ments of IPC/JEDEC J-STD-020.

Suitable for use in SnPb or Pb-free soldering processes.

100% matte tin (Sn) plating.

RT9246

Package Type

C : TSSOP-28

Operating Temperature Range

P : Pb Free with Commercial Standard

G : Green (Halogen Free with Commer-

cial Standard)