IR3522

Page 1

V3.01

DATA SHEET

DDR & VTT CONTROL IC

DESCRIPTION

The IR3522 Control IC combined with IR3506 xPHASE3

power solution. The IR3522 provides control functions for both the VTT (single phase) and VDDR

(multiphase) power rails which can interfaces with any number of IR3506 ICs each driving and monitoring

a single phase to power any number of DDR3 DIMMs. The xPHASE3

supply that is smaller, more flexible, and easier to design while providing higher efficiency than

conventional approaches.

FEATURES

•

I

•

I

•

Four different I

•

Four different VREF1 voltages are selectible using 2 VID pins if I

•

VTT tracking defaults to ½ the VDD Remote Sense Amp output voltage

•

Power Good output driven by an external bias input

•

VDD to VTT overvoltage protection

•

Soft-Stop turn-off to ensure VDDR and Vtt tracking

•

Fault activated Crowbar pin to drive external NMOS devices for external output voltage protection

•

Pin programmable slew rate of I

•

0.5% overall VDD system set point accuracy

•

Remote sense amplifiers provide differential sensing and requires less than 50uA bias current

•

Pin programmable per phase switching frequency of 250kHz to 1.5MHz

•

Complete protection including over-current, over-voltage, open remote sense, and open control

APPLICATION CIRCUIT

CSS/DEL

CVREF

ROSC

DDR SENSE +

DDR SENSE -

ROCSET1

CVCCL

RVR EF

To Vtt

Remote

Sense

SCL

PHSIN

12V

PGOOD

PHSOUT

VTT SENSE +

VTT SENSE -

SDA

ROCSET2

CLKOUT

VREF1

PGBIAS

2

EN ABLE

3

IIN 2

4

OCSET2

7

CROWBAR

22

II N1

21

EAOUT1

17

VREF1

19

AD DR2

6

ROSC

23

LGND

24

SD A

1

SS/ DEL1

20

OCSET1

18

AD DR1

5

EAOUT2

8

IR3522

CONTROL

IC

ISHARE1

EAOUT1

CCP22

CCP21

RPGBIAS

ENABLE

RCP2

12V

R FB21

CFB2

RFB22

CROWBAR

Drives NMOS crowbar

devices at VTT and

VDDR rails

To Phase IC

VCCL & GATE

DRIVE BIAS

VCCL

To Converters

To VDD

Remote

Sense

2 wire Digital

Daisy Chain Bus

to Phase ICs

Phase Clock Input to

Last Phase IC of VDD

ISHARE2

R CP1

CCP11

RFB11

CFB1

RFB12

CCP12

EAOUT2

5 Wire Analog

Phase IC

Control Bus

VCCL

Figure 1 – IR3522 Application Circuit