®
ISL6227
Data Sheet
March 2004
FN9094.1
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
r
DS(ON)
as the current sense element.
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
drop across the r
DS(ON)
of the lower MOSFET. If more precise
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
• r
DS(ON)
current sensing
• 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 Available as an Option
Ordering Information
PART #
ISL6227CA
ISL6227CAZ
(Note)
ISL6227CA-T
ISL6227CAZ-T
(Note)
TEMP. (°C)
-10 to 100
-10 to 100
-10 to 100
-10 to 100
PACKAGE
28 Ld SSOP
28 Ld SSOP (Pb-Free)
PKG.
DWG. #
M28.15
M28.15
28 Ld SSOP Tape and Reel M28.15
28 Ld SSOP Tape and Reel M28.15
(Pb-Free)
NOTE: Intersil Pb-Free products employ special Pb-free material
sets; molding compounds/die attach materials and 100% matte tin
plate termination finish, which is 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-020B.
Pinout
ISL6227 (28 LD SSOP)
TOP VIEW
GND 1
LGATE1 2
PGND1 3
PHASE1 4
UGATE1 5
BOOT1 6
ISEN1 7
EN1 8
VOUT1 9
VSEN1 10
OCSET1 11
28 VCC
27 LGATE2
26 PGND2
25 PHASE2
24 UGATE2
23 BOOT2
22 ISEN2
21 EN2
20 VOUT2
19 VSEN2
18 OCSET2
17 SOFT2
16 PG2/REF
15 PG1
Applications
• Notebook PCs and Desknotes
• Hand-held portable instruments
1
• Tablet PCs/Slates
SOFT1 12
DDR 13
VIN 14
INTERSIL [ INTERSIL CORPORATION ]
