Features

• Four Monolithic Synchronous Buck DC/DCs (1A/1A/500mA/500mA)
• Buck DC/DCs Can Be Paralleled to Deliver Up to 2× Current with a Single Inductor
• Independent 1A Boost and 1A Buck-Boost DC/DCs
• Dual String I²C Controlled 40V LED Driver
• I²C Programmable Output Voltage, Operating Mode, and Switch Node Slew Rate for All DC/DCs
• I²C Read Back of DC/DC, LED Driver, Fault Status
• I²C Slave Address Options: LTC3675 = 0001001X, LTC3675-1 = 0110100X
• Maskable Interrupts to Report DC/DC, V_IN and Die Temperature Faults
• Pushbutton ON/OFF/RESET
• Always-On 25mA LDO
• Low Quiescent Current: 16μA (All DC/DCs Off)
• 4mm × 7mm × 0.75mm 44-Lead QFN Package

Typical Application

Description

The LTC®3675/LTC3675-1 are a digitally programmable high efficiency multioutput power supplies plus dual string LED driver ICs optimized for high power single cell Li-Ion/Polymer applications. The DC/DCs consist of four synchronous buck converters (1A/1A/500mA/500mA), one synchronous boost DC/DC (1A), and one buck-boost DC/ DC (1A) all powered from a 2.7V to 5.5V input. The 40V LED driver can regulate up to 25mA of current through two LED strings with up to 10 LEDs each. The LED driver may also be configured as a general purpose high voltage boost converter.

DC/DC enables, output voltages, switch slew rates and operating modes may all be independently programmed over I²C or used in standalone mode via simple I/O and power-up defaults. The buck DC/DCs may be used independently or paralleled to achieve higher output currents with a shared inductor. LED enable, 60dB brightness control and up/down gradation are programmed using I²C. Alarm levels for low V_IN and high die temperature may also be programmed via I2C with a maskable interrupt output to monitor DC/DC and system faults.

Pushbutton ON/OFF/RESET control and a power-on reset output provide flexible and reliable power-up sequencing. The LTC3675/LTC3675-1 are available in a low profile (0.75mm), thermally enhanced 44-lead 4mm × 7mm QFN package.