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ISL6227

Dual Mobile-Friendly PWM Controller with

DDR Option

The ISL6227 dual PWM controller delivers high efficiency

precision voltage regulation from two synchronous buck DC/DC

converters. It was designed especially to provide power

regulation for DDR memory, chipsets, graphics and other

system electronics in Notebook PCs. The ISL6227’s wide

input voltage range capability allows for voltage conversion

directly from AC/DC adaptor or Li-Ion battery pack.

Automatic mode transition of constant-frequency synchronous

rectification at heavy load, and hysteretic (HYS) diode-

emulation at light load, assure high efficiency over a wide range

of conditions. The HYS mode of operation can be disabled

separately on each PWM converter if constant-frequency

continuous-conduction operation is desired for all load levels.

Efficiency is further enhanced by using the lower MOSFET

Voltage-feed-forward ramp modulation, current mode control,

and internal feedback compensation provide fast response to

input voltage and load transients. Input current ripple is

minimized by channel-to-channel PWM phase shift of 0°, 90° or

180° (determined by input voltage and status of the DDR pin).

The ISL6227 can control two independent output voltages

adjustable from 0.9V to 5.5V, or by activating the DDR pin,

transform into a complete DDR memory power supply solution.

In DDR mode, CH2 output voltage VTT tracks CH1 output

voltage VDDQ. CH2 output can both source and sink current, an

essential power supply feature for DDR memory. The reference

voltage VREF required by DDR memory is generated as well.

In dual power supply applications the ISL6227 monitors the

output voltage of both CH1 and CH2. An independent PGOOD

(power good) signal is asserted for each channel after the

soft-start sequence has completed, and the output voltage is

within PGOOD window. In DDR mode CH1 generates the only

PGOOD signal.

Built-in overvoltage protection prevents the output from going

above 115% of the set point by holding the lower MOSFET on

and the upper MOSFET off. When the output voltage re-enters

regulation, PGOOD will go HIGH and normal operation

automatically resumes. Once the soft-start sequence has

completed, undervoltage protection latches the offending

channel off if the output drops below 75% of its set point value.

Adjustable overcurrent protection (OCP) monitors the voltage

current-sensing is required, an external current sense resistor

may be used.

Features

• Provides regulated output voltage in the range 0.9V–5.5V

• Operates from an input battery voltage range of 5V to 24V

or from 3.3V/5V system rail

• Complete DDR1 and DDR2 memory power solution with

VTT tracking VDDQ/2 and a VDDQ/2 buffered reference

output

• Flexible PWM or HYS plus PWM mode selection with HYS

diode emulation at light loads for higher system efficiency

• Excellent dynamic response with voltage feed-forward and

current mode control accommodating wide range LC filter

selections

• Undervoltage lock-out on VCC pin

• Power-good, overcurrent, overvoltage, undervoltage

protection for both channels

• Synchronized 300kHz PWM operation in PWM mode

• Pb-free plus anneal available (RoHS compliant)

Applications

• Notebook PCs and Desknotes

• Tablet PCs/Slates

• Hand-held portable instruments

Ordering Information

PART #

PART

MARKING

TEMP.

RANGE (°C)

PACKAGE

PKG.

DWG. #

ISL6227CA

ISL6227CA

-10 to +100 28 Ld QSOP M28.15

ISL6227CAZ

(Note)

ISL6227CAZ

-10 to +100 28 Ld QSOP

(Pb-free)

M28.15

ISL6227IA

ISL6227IA

-40 to +100 28 Ld QSOP M28.15

ISL6227IAZ

(Note)

ISL6227IAZ

-40 to +100 28 Ld QSOP

(Pb-free)

M28.15

ISL6227HRZ

(Note)

ISL6227HRZ

-10 to +100 28 Ld QFN

(Pb-free)

L28.5x5

ISL6227IRZ

(Note)

ISL6227IRZ

-40 to +100 28 Ld QFN

(Pb-free)

L28.5x5

Add -T to part number for Tape and Reel

NOTE: Intersil Pb-free plus anneal products employ special Pb-free

material sets; molding compounds/die attach materials and 100% matte

tin plate termination finish, which are RoHS compliant and compatible

with both SnPb and Pb-free soldering operations. Intersil Pb-free

products are MSL classified at Pb-free peak reflow temperatures that

meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774

Copyright Intersil Americas Inc. 2004-2006. All Rights Reserved

All other trademarks mentioned are the property of their respective owners.

December 21, 2006

Data Sheet

FN9094.4