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Switch Mode USB Power Manager & Triple Buck Regulator Provides Faster Charge Time & Minimizes Heat
MILPITAS, CA - May 14, 2007 - Linear Technology Corporation
announces the LTC3555, the first in a family of next generation
multi-function power management solutions for Li-Ion/Polymer
battery applications. The LTC3555 integrates a switching PowerPath™
manager, a standalone battery charger, an ideal diode, I2C control,
three high efficiency synchronous buck regulators plus an always-on
LDO, all in a compact, low-profile 4mm x 5mm QFN package. The
LTC3555's PowerPath control feature seamlessly manages power flow
between an AC wall adapter or USB port, Li-Ion battery and system
load while its "instant-ON" operation ensures system load power
even with a dead or missing battery. For fast charging, the
LTC3555's switching input stage converts nearly all of the 2.5W
available from the USB port to charging current, enabling up to
700mA from a 500mA limited USB supply and up to 1.5A when wall
powered. An internal 180milliOhm ideal diode plus optional external
ideal diode controller provide a low loss power path, further
minimizing heat generation and maximizing efficiency.

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The LTC3555's three integrated synchronous buck regulators
feature 100% duty cycle operation and are capable of delivering
output currents of 1A/400mA/400mA, respectively, with adjustable
output voltages down to 0.8V. The internal low RDS(ON) switches
enable efficiency as high as 94%, maximizing battery run time. In
addition, Burst Mode® operation optimizes efficiency at light loads
with a quiescent current of only 35uA per regulator (
The LTC3555 features USB-compatible programmable current limiting
to 100mA/500mA/1A, while its Bat-Track™ adaptive output control
enables high efficiency charging and reduces power dissipation.
Standalone autonomous operation simplifies design, eliminating the
need for an external microprocessor for charge termination. To
preserve battery energy, the LTC3555 draws |
The LTC3555 is available from stock in a compact, low-profile
(0.75mm) 4mm x 5mm QFN-28 package. Pricing starts at $4.65 each for
1,000-piece quantities.
| Summary of Features: LTC3555 |
| • |
Complete Multi-Function PMIC: Switching Power
Manager, Li-Ion/Polymer Battery Charger, Three Buck
Regulators & LDO |
| • |
Thermally Enhanced, Low Profile (0.75mm)
28-Lead 4mm x 5mm QFN Package |
| POWER MANAGER & BATTERY
CHARGER |
| • |
High Efficiency Switching PowerPath Controller with
Bat-Track Adaptive Output Control |
| • |
Programmable Input Current Limit (100mA/500mA/1A) |
| • |
Maximum Charge Current Programmable up to 1.5A
from Wall Adapter |
| • |
180mOhm Internal Ideal Diode Plus Optional
External Ideal Diode Controller Provides Low Loss
Power Path from Battery to Load |
| DC/DCs |
| • |
Three High Efficiency 2.25 MHz Synchronous
Buck Regulators: 1A, 400mA, 400mA IOUT |
| • |
Adjustable Output Voltage Range: 0.8V to VBAT |
| • |
Burst Mode Operation with Low IQ: 35uA per Regulator |
| • |
Always-On 25mA/3.3V LDO |
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Multi-Function Switching Power Manager + Battery Charger
+ Triple Sync Buck + LDO
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