Switch Mode USB Power Manager from Linear Technology

5th March 2009

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Datasheet

Linear Technology has announced the LTC3586, the latest and most highly integrated PMIC in a family of multi-function, compact power management solutions for Li-Ion/Polymer battery applications. The LTC3586 integrates a switching PowerPath manager, a stand-alone battery charger, always-on LDO, and 4 high efficiency synchronous switching regulators: 1 buck-boost, 1 boost, and 2 buck regulators, all in a compact, low-profile 4mm x 6mm QFN package.

The LTC3586’s PowerPath control seamlessly manages power flow between multiple input sources such as a wall adapter or USB port and the Lithium battery while preferentially providing power to the system load. In addition, its instant-ON operation ensures system load power even with a dead battery. For fast charging, the LTC3586’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 or 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.

The LTC3586’s buck-boost regulator can deliver up to 1A continuously and is ideal for efficiently regulating a 3.3V output over the full Lithium battery voltage range, down to 2.75V. The LTC3586’s two buck regulators feature 100% duty cycle operation and are capable of delivering output currents of 400mA each, with adjustable output voltages down to 0.8V. The boost regulator is capable of at least 800mA output current and is programmable up to a 5V output. The LTC3586’s internal low RDS(ON) switches enable switching buck and buck-boost efficiencies as high as 94%, maximizing battery run time. In addition, Burst Mode® operation optimizes efficiency at light loads with a quiescent current of only 25uA for the buck-boost regulator and only 35uA for each buck regulator (<1uA each in shutdown for all). The high 2.25MHz switching frequency allows the use of tiny low cost capacitors and inductors less than 1mm in height. Furthermore, all regulators are stable with ceramic output capacitors, achieving very low output voltage ripple.

The LTC3586 features USB-compatible programmable input current limiting to 100mA/500mA/1A, while its Bat-Track™ adaptive output control enables high efficiency battery charging with minimum power dissipation. To preserve battery energy, the LTC3586 draws only 44uA in suspend mode. The charger is compatible with inputs up to 5.5V (7V absolute maximum transient for added robustness).