ISL8112 Datasheet, PDF (1/27 Pages) Intersil Corporation – High Light-Load Efficiency, Dual-Output Main Power Supply Controllers

®
Data Sheet
August 10, 2010
ISL8112
FN6396.1
High Light-Load Efficiency, Dual-Output,
Main Power Supply Controllers
ISL8112 is a dual-output Synchronous Buck controller with 2A
integrated driver. It features high light load efficiency which is
especially preferred in systems concerned with high efficiency
in wide load range, like the battery powered system. ISL8112
includes two constant on-time PWM controllers. Either of the
two outputs can operate in output fixed mode or adjustable
mode. In fixed mode, one output can be 5V or 3.3V and the
other can output 1.5V or 1.05V. In output adjustable mode,
one output can be 0.7V to 5.5V, and the other output can
range from 0V to 2.5V (sensing output voltage directly) or up
to 5V (using resistor divider voltage for voltage sensing). This
device also features a linear regulator providing 3.3V/5V, or
adjustable from 0.7V to 4.5V via LDOREF. The linear
regulator provides up to 100mA output current with automatic
linear-regulator bootstrapping to the BYP input. When in
switch over, the LDO output can source up to 200mA.
ISL8112 includes on-board power-up sequencing, the power-
good (PGOOD_) outputs, digital soft-start, and internal soft-
stop output discharge that prevents negative voltages on
shutdown.
ISL8112 is implemented with constant on-time PWM control
scheme which need no sense resistors and provides 100ns
response to load transients while maintaining a relatively
constant switching frequency. The unique ultrasonic pulse-
skipping mode maintains the switching frequency above
25kHz, eliminating undesired audible noises in low frequency
operation at light load. Other features include pulse skipping
which maximizes efficiency in light-load applications, and
fixed-frequency PWM mode which reduces RF interference in
sensitive applications.
Ordering Information
PART
NUMBER
(Note)
PART
MARKING
TEMP.
RANGE
(°C)
PKG.
PACKAGE DWG. #
ISL8112IRZ* ISL8112 IRZ -40 to +100 32 Ld QFN
(Pb-free)
L32.5x5B
*Add “-T” suffix for tape and reel. 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.
Features
• Wide Input Voltage Range 5.5V to 25V
• Constant ON-TIME Control with 100ns Load-Step
Response
• Dual Fixed Outputs of 1.05V (3.3V) and 1.5V (5.0V), or
Adjustable Outputs of 0.7V to 5.5V (SMPS1) and 0V to
2.5V/5V (SMPS2), ±1.5% Accuracy
• Adjustable Switching Frequency: 400/500kHz,
300/400kHz, 200/300kHz
• Very High Light Load Efficiency (Skip Mode)
• 5mW Quiescent Power Dissipation
• ±1.5% (LDO): 100mA, 200mA (Switch Over)
• 3.3V Reference Voltage ±2.0%: 5mA
• 2.0V Reference Voltage ±1.0%: 50µA
• Temperature Compensated r_DS(ON) Current Sensing
• Programmable Current Limit with Foldback Capability
• Selectable PWM, Skip or Ultrasonic Mode
• Independent PGOOD1 and PGOOD2 Comparators
• Soft-Start with Pre-Biased Output and Soft-Stop
• 1.7ms Digital Soft-Start and Independent Shutdown
• Independent ENABLE
• Thermal Shutdown
• Extremely Low Components Count
• Pb-Free Available (RoHS Compliant)
Applications
• Power Supply for Telecom/Datacom and POL
• System Requiring High Efficiency in Wide Load Range
• Compact Design with Minimum Components Count
• PDAs and Mobile Communication Devices
• 3- and 4-Cell Li+ Battery-Powered Devices
• DDR1, DDR2, and DDR3 Applications
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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