Date: 30/07/2009

Linear's multi-function power management ICs for portable Li-Ion/polymer battery applications

Linear technology has made available the LTC3577, LTC3577-1, LTC3577-3 and LTC3577-4, power management integrated circuit devices for portable Li-Ion/Polymer battery applications.

The LTC3577/-X integrates a USB-compatible linear PowerPath manager, a standalone battery charger, overvoltage protection, 10-LED driver, pushbutton on/off control, three high efficiency synchronous buck regulators and two LDOs.

Key features of LTC3577 families are,

Charge Current Programmable up to 1.5A from Wall Adapter Input
Seamless Transition Between Input Power Sources: Li-Ion/Polymer Battery, USB, 5V Low Loss Power Path from Battery to Load
Standalone Autonomous Operation
High Temperature Battery Voltage Reduction Circuit for Improved Battery Safety & Reliability
Instant-On Operation with Discharged Battery
DC/DCs
Buck Regulator Adjustable Output Voltage Range: 0.8V to VBAT
Buck Regulator Output Currents: 800mA, 500mA, 500mA
Dual 150mA Current Limited LDOs

Additional features are,
40V Series Backlight 10-LED Driver with 60dB Brightness Control & Gradation via I2C
Overvoltage Protection for USB/Wall Input (up to 30V)
Pushbutton On/Off Control with System Reset
Battery Float Voltage: 4.2V (LTC3577, LTC3577-3), 4.1V (LTC3577-1, LTC3577-4)
SiRF Atlas IV Chipset Compatible (LTC3577-3, LTC3577-4)

These ICs are suitable for portable device applications including personal navigation devices (PNDs), digital media/video broadcasting (DMB/DVBs), digital/satellite radio, media players, universal remotes, photo viewers and portable medical and industrial devices.






The LTC3577/-1 can control an external high-voltage buck regulator to achieve high efficiency Bat-Track charging and power path control from a high voltage source, reducing power dissipation. The internal 200mOhm ideal diode, plus an optional external ideal diode controller provide a low loss power path to the load when input current is limited or unavailable.

The LTC3577/-X's three integrated synchronous buck regulators feature 100% duty cycle operation and delivers output currents of 800/500/500mA respectively, with adjustable output voltages down to 0.8V. A high 2.25MHz switching frequency allows the use of tiny low cost capacitors and inductors less than 1mm in height. Internal low RDS(ON) switches enable efficiencies as high as 95%, further maximizing battery run time. In addition, I2C-controlled Burst Mode operation optimizes efficiency at light loads with a quiescent current of only 20uA per regulator (<1uA in shutdown).


Package: compact 4mm x 7mm QFN-44 package
Price: Each $4.95 for 1k pieces.
For more details visit www.linear.com.