Linear reveals PMIC for Li-Ion/polymer batteries

Linear Technology has announced the LTC3586, the latest and most highly integrated PMIC in a family of multi-function, compact power management systems for Li-Ion/polymer battery applications.

The LTC3586 integrates a switching Powerpath manager, a standalone battery charger, always-on LDO, and four high-efficiency synchronous switching regulators: one buck-boost, one boost and two buck regulators, all in a compact, low-profile 4mm x 6mm QFN package.

Its 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.

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 the 2.5W available from the USB port to charging current, delivering up to 700mA from a 500mA limited USB supply or up to 1.5A when wall-powered.

An internal 180-milliohm ideal diode plus optional external ideal diode controller provide a low-loss power path, further minimising heat generation and maximising 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.

Its two buck regulators feature 100 per cent 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 allow switching buck and buck-boost efficiencies as high as 94 per cent, maximising battery run time.

Burst-mode operation optimises efficiency at light loads with a quiescent current of only 25 microamps for the buck-boost regulator and 35 microamps for each buck regulator (<1 microamp 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.

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 allows high-efficiency battery charging with minimum power dissipation.

To preserve battery energy, it draws only 44 microamps in suspend mode.

The charger is compatible with inputs up to 5.5V (7V absolute maximum transient for added robustness).

The LTC3586 is available from stock in a compact, low-profile (0.75mm) 4mm x 6mm QFN-38 package.

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