July 30, 2013 – Linear Technology Korea (CEO Hong Sa-gwak) announced the launch of cutting-edge PMIC power management solutions (LTC3676 and LTC3676-1) suitable for mobile processors, including Freescale's i.MX6 series, PXA, OMAP, ARM Cortex and other advanced mobile microprocessor-based systems.

The LTC3676 and LTC3676-1 feature four synchronous step-down DC/DC converters for core, memory, I/O, and SoC (System-on-chip), along with three 300mA LDO (low dropout) regulators for low-noise analog power supplies and dynamic control & sequencing functions. The LTC3676-1 includes a 1.5A buck regulator for source/sink and tracking operation and a VTTR reference output function for DDR, which replaces the LDO4 enable and feedback pins of the LTC3676. Configurable superior power sequencing performance, dynamic voltage scaling output voltage control, push-button interface controller, as well as regulator control functions through I2C interface reporting transient conditions and interrupt outputs support multiple regulators.

The LTC3676's four fixed-frequency current mode buck switching regulators are internally compensated and provide maximum output currents of 2.5A, 2.5A, 1.5A, and 1.5A respectively, with full I2C control features including selectable switching frequency (2.25MHz or 1.125MHz) and phase. The device's power-on default frequency is 2.25MHz and features switch edge rate adjustment capability for EMI reduction. Each buck has a dynamically controlled DAC-based output reference and an external feedback pin to set the required output voltage range. The IC's operating mode can be set using the I2C interface. Configurable operating modes include pulse skipping (supporting 100% duty cycle), Burst Mode® operation (advantageous for optimal efficiency at low output loads) or forced continuous mode (minimizing output voltage ripple at light loads and optimizing dynamic slew control between voltage output set points).

The LTC3676 features four LDOs for low-noise analog power supplies and includes three 300mA rails with different combinations of fixed and I2C-selectable voltage options. Two of these regulators provide adjustable output features. Another LDO uses a resistor divider with an always-on 25mA power supply for output voltage setting.

The LTC3676's feature-rich I2C serial port is used to control regulator enable, output voltage level, dynamic voltage scaling, operating mode, and status reporting. Regulator startup can be sequenced through the I2C port or by connecting regulator outputs to enable pins in the desired order. System power-on, power-off, and reset functions are controlled through the push-button interface, pin input, or I2C interface. Through I2C-defined power-down sequencing, each regulator can be assigned to one of four turn-off time slots. Other features include adjustable temperature alarm and shutdown, adjustable low voltage alarm and lockout, power good, interrupt request output (/IRQ) and reset output (/RSTO), and interface signals such as voltage standby (VSTB) pin. The VSTB pin can select between programmed operating and standby output voltages simultaneously on up to four rails.

The LTC3676/-1 is now available in a low-profile (0.75mm) 40-pin 6mm × 6mm exposed pad QFN package with enhanced thermal performance. Based on quantity of 1,000 units, the grade E product is $5.50 per unit. Both grade E and grade I versions have an operating junction temperature range of -40°C to +125°C. The grade H version has an operating junction temperature of -40°C to +150°C. For more information, refer to www.linear.com/product/LTC3676.

Product Features: LTC3676 & LTC3676-1

• Quad I2C adjustable high-efficiency step-down DC/DC converters: 2.5A, 2.5A, 1.5A, 1.5A
• Three 300mA LDO regulators (two adjustable)
• DDR power solution with VTT & VTTR reference
• System reset with push-button ON/OFF control
• Independent enable pin straps or I2C sequencing
• Programmable automatic power-down control
• Dynamic voltage scaling
• Power good and reset functions
• Selectable 2.25MHz or 1.12MHz switching frequency & phase
• Always-enabled 25mA LDO regulator
• 12μA standby current
• Available in 40-pin 6mm × 6mm QFN package