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®
FN9095.2
ISL6228
High-Performance Dual-Output Buck
Controller for Notebook Applications
The ISL6228 IC is a dual channel synchronous-buck PWM
controller featuring Intersil's Robust Ripple Regulator (R
3
)
technology that delivers truly superior dynamic response to
input voltage and output load transients. Integrated
MOSFET drivers and bootstrap diodes result in fewer
components and smaller implementation area.
Intersil’s R
3
technology combines the best features of fixed-
frequency and hysteretic PWMs while eliminating many of
their shortcomings. R
3
technology employs an innovative
modulator that synthesizes an AC ripple voltage signal V
R
,
analogous to the output inductor ripple current. The AC signal
V
R
enters a window comparator where the lower threshold is
the error amplifier output V
COMP
, and the upper threshold is a
programmable voltage reference V
W,
resulting in generation
of the PWM signal. The voltage reference V
W
sets the
steady-state PWM frequency. Both edges of the PWM can be
modulated in response to input voltage transients and output
load transients, much faster than conventional fixed-
frequency PWM controllers. Unlike a conventional hysteretic
converter, each channel of the ISL6228 has an error amplifier
that provides ±1% voltage regulation at the FB pin.
The ISL6228 has a 1.5ms digital soft-start and can be
started into a pre-biased output voltage. A resistor divider is
used to program the output voltage setpoint. The ISL6228
operates in continuous-conduction-mode (CCM) in heavy
load, and in diode-emulation-mode (DEM) in light load to
improve light-load efficiency. In CCM, the controller always
operates as a synchronous rectifier. In DEM, the low-side
MOSFET is permitted to stay off, blocking negative current
flow into the low-side MOSFET from the output inductor.
Pinout
ISL6228 (28 LD 4x4 TQFN)
Features
• High performance R
3
technology
• Fast transient response
• ±1% regulation accuracy: -40°C to +100°C
• Individual power stage input rail for each channel
• Wide input voltage range: +3.3V to +25V
• Output voltage range: +0.6V to +5V
• Diode emulation mode for increased light load efficiency
• Programmable PWM frequency: 200kHz to 600kHz
• Pre-biased output start-up capability
• Integrated MOSFET drivers and bootstrap diode
• Internal digital soft-start
• Power good monitor
• Fault protection
- Undervoltage protection
- Soft crowbar overvoltage protection
- Inductor DCR overcurrent protection
- Over-temperature protection
- Fault identification by PGOOD pull-down resistance
• Pb-free (RoHS compliant)
Applications
• General purpose switching buck regulators
• PCI express graphical processing unit
• Auxiliary power rail
•VRM
• Network adaptor
GND
VO2
FB2
PGOOD2
EN1
FB1
OCSET1
VO1
VCC1
FSET2
VCC2
VIN1
FSET1
28
26
25
27 24
23
1
2
3
4
5
6
8
10
11
912
13
21
20
19
18
17
16
PHASE1
UGATE1
PVCC2
LGATE2
BOOT2
LGATE1
PGND1
EN2
OCSET2
VIN2
PHASE2
PGND2
PGOOD1
7
14
BOOT1
15
PVCC1
22
UGATE2
Ordering Information
PART NUMBER
(Note)
PART
MARKING
TEMP
(°C)
PACKAGE
(Pb-Free)
PKG.
DWG. #
ISL6228HRTZ 6228HRTZ -10 to +100 28 Ld 4x4 TQFN L28.4x4A
ISL6228HRTZ-T* 6228HRTZ -10 to +100 28 Ld 4x4 TQFN
Tape and Reel
L28.4x4A
ISL6228IRTZ 6228IRTZ -40 to +100 28 Ld 4x4 TQFN L28.4x4A
ISL6228IRTZ-T* 6228IRTZ -40 to +100 28 Ld 4x4 TQFN
Tape and Reel
L28.4x4A
*Please refer to TB347 for details on reel specifications.
NOTE: These Intersil Pb-free plastic packaged products employ special Pb-
free material sets; molding compounds/die attach materials and 100% matte
tin plate PLUS ANNEAL - e3 termination finish, which is 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.
Data Sheet May 7, 2008
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
| Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2007, 2008. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
