IR3522 Datasheet, PDF (1/32 Pages) International Rectifier – XPHASE3TM DDR & VTT CONTROL IC

IR3522
DATA SHEET
XPHASE3^TM DDR & VTT CONTROL IC
DESCRIPTION
The IR3522 Control IC combined with IR3506 xPHASE3^TM Phase ICs implements a full featured DDR3
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^TM architecture delivers a power
supply that is smaller, more flexible, and easier to design while providing higher efficiency than
conventional approaches.
FEATURES
• I²C interface programs 1.025V< VREF1<1.612V, the VDD output voltage reference
• I²C also programs the VTT tracking ratio ± 25 %, and provides digital ON/OFF control
• Four different I²C addresses are selectible using 2 ADDR pins
• Four different VREF1 voltages are selectible using 2 VID pins if I²C communication is not available
• 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 I²C programmed VREF1 voltage transitions
• 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
12V
VCCL
PGOOD
SCL
SDA
CVCCL
12V To Converters
VCCL To Phase IC
VCCL & GATE
DRIVE BIAS
Phase Clock Input to
PHSIN ^{Last Phase IC of VDD}
PHSOUT
CLKOUT
2 wire Digital
Daisy Chain Bus
to Phase ICs
ENABLE
RPGBIAS
ROCSET2
1 _{SD A}
2 _PGBIAS
3 _{EN ABLE}
4
IIN2
5 _{AD DR1}
6
AD DR2
7 _OCSET2
8 _EAOUT2
IR3522
CONTROL
IC
LGND ²⁴
ROSC ²³
CROWBAR ²²
21
IIN1
SS/ DEL1 ²⁰
19
VREF 1
OCSET1 ¹⁸
EAOUT1 ¹⁷
ROSC
RVR EF
ROCSET1
CSS/DEL
CVREF
Drives NMOS crowbar
CROWBAR devices at VTT and
VDDR rails
To Vtt
Remote
Sense
VTT SENSE +
VTT SENSE -
Page 1
RCP2 CCP21
CCP22
RFB22 CFB2
R FB21
CFB1 RFB12
RFB11
R CP1 CCP11
CCP12
Figure 1 – IR3522 Application Circuit
ISHARE1
EAOUT1
VREF1
EAOUT2
ISHARE2
5 Wire Analog
Phase IC
Control Bus
DDR SENSE +
DDR SENSE -
To VDD
Remote
Sense
V3.01