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High Power, Eight-Channel I2C-Controlled PMIC for Portable Processor Systems
MILPITAS, CA - August 3, 2010 - Linear Technology Corporation
announces the LTC3589, a complete power
management solution for portable processors such as i.MX, PXA, ARM,
OMAP and other advanced portable microprocessor systems. The device
features eight independent rails, with dynamic control and
sequencing, in a compact QFN package. These rails supply power to
the processor core, SDRAM, system memory, PC cards, always-on real
time clock (RTC) and a variety of other functions. The LTC3589
contains three high current, high efficiency step-down regulators,
a high current/high efficiency buck-boost regulator, and four low
noise, low dropout linear regulators (LDOs). Supporting the
multiple regulators is a highly configurable power sequencing
capability, dynamic voltage scaling output voltage control, a
pushbutton interface controller, as well as regulator control via
an I2C interface with extensive status reporting and an interrupt
output.
The LTC3589's three constant frequency current-mode buck switching
regulators are internally compensated and provide up to 1A, 1A and
1.6A output currents, and have complete I2C-control, including
selectable switching frequencies of 2.25MHz or 1.125MHz and
phasing. The device's power-on default frequency is 2.25MHz with
switch edge rate adjustment for reduced EMI. Each buck has a
dynamically controlled DAC-based input reference and an external
feedback pin to set the nominal output voltage range. Three
operating modes can be set using the I2C interface: pulse-skipping
(supports 100% duty cycle), Burst Mode® operation (advantageous for
best efficiency at low output loads), or forced continuous
(minimizes output voltage ripple at light loads and optimizes
dynamic slew control between voltage output set points).
The LTC3589's single inductor, synchronous buck-boost converter
generates a user-programmable output voltage rail from 2.5V to 5V.
Utilizing a proprietary switching algorithm, the buck-boost
converter maintains high efficiency and low noise operation with
input voltages above, below or equal to the regulated output rail.
The buck-boost error amplifier uses a fixed 0.8V reference and the
output voltage is set by an external resistor divider. Burst Mode
operation is enabled through the I2C control registers. No external
compensation components are required.
The LTC3589 also has four LDOs for low noise analog supplies,
including three 250mA rails with different combinations of fixed,
adjustable and I2C-selectable voltage options. The other LDO is an
always-on 25mA supply with a resistor-programmable output
voltage.
The LTC3589's versatile I2C serial port is used to control
regulator enables, output voltage levels, dynamic voltage scaling
and slew rate, operating modes and status reporting. Regulator
start-up is sequenced by connecting regulator outputs to enable
pins in the desired order or via the I2C port. System power-on,
power-off and reset functions are controlled by a pushbutton
interface, pin inputs, or I2C interface.
The LTC3589 is available from stock in a thermally enhanced, low
profile (0.75mm) 40-pin 6mm x 6mm exposed pad QFN package.
1000-piece pricing starts at $4.65 each for the E grade and $5.35
each for the I grade, both with operating junction temperature
range of -40°C to +125°C. An H grade version with operating
junction temperature of -40°C to +150°C is also available, priced
starting at $5.70 each in 1000-piece quantities. For more
information, visit http://www.linear.com/3589.
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Summary of Features: LTC3589
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Eight Output, High Power 3 Buck + 1 Buck-Boost +  Click Photo for High-Res Image |