The LTC3375 is a digitally programmable high efficiency multi-output power supply IC. The DC/DCs consist of eight synchronous buck converters (IOUT up to 1A each) all powered from independent 2.25V to 5.5V input supplies.
DC/DC enables, output voltages, operating modes, and phasing may all be independently programmed over I2C or used in standalone mode via simple I/O with power-up defaults. The DC/DCs may be used independently or in parallel to achieve higher output currents of up to 4A per output with a shared inductor. Alarm levels for high die temperature may also be programmed via I2C with a maskable IRQ output for monitoring DC/DC and system faults.
The LTC3375 from Linear Technology is a highly-integrated general-purpose power management solution for systems requiring multiple low voltage power supplies. The device features eight independent 1A channels with I²C control, flexible sequencing and fault monitoring in a compact QFN package.
Each channel is a high efficiency synchronous step-down regulator with its own independent 2.25V to 5.5V input supply and an output voltage range of 0.425V to VIN. In addition, the LTC3375’s buck DC/DCs may be connected in parallel to achieve higher output currents up to 4A per output with a single shared inductor. Up to four adjacent regulators can be combined, resulting in 15 different possible output configurations. All of the switching regulators are internally compensated and need only external feedback resistors to set the default output voltage.
The LTC3375’s pushbutton ON/OFF/RESET control, power-on reset and watchdog timer provide flexible and reliable power-up sequencing and system monitoring. All buck output voltages can be adjusted via I²C for margining or power optimization. The LTC3375 features a programmable and synchronizable 1MHz to 3MHz oscillator with a 2MHz default switching frequency.
The device also contains a high voltage input shunt regulator controller, and quiescent current is only 11µA with all DC/DCs off. It is ideal for a wide variety of multichannel applications including industrial, automotive and communications systems.
Adjacent buck regulators can be combined in a master/slave configuration by connecting their VIN and SW pins together, and connecting the slave bucks’ FB pin(s) to the input supply. The switching regulators offer two operating modes: Burst Mode® operation (power-up default mode) for higher efficiency at light loads, and forced continuous PWM mode for lower noise at light loads.
The I²C interface can be used to select mode of operation, phasing, feedback regulation voltage and switch slew rate. The bucks have forward and reverse current limiting, soft-start to limit inrush current during start-up, short-circuit protection and slew rate control for lower radiated EMI.
Other features include a die temperature monitor output (readable via I²C or the analog voltage on the TEMP pin), which indicates internal die temperature and an overtemperature (OT) warning function, indicating high die temperature.
The LTC3375 is available in a thermally enhanced, low profile (0.75mm) 48-pin 7mm x 7mm exposed pad QFN package. E- and I-grades are specified over an operating junction temperature range of -40°C to +125°C, and the H-grade features operation from -40°C to +150°C. 1000-piece pricing starts at $5.45 each for the E-grade.
For more information, visit www.linear.com/product/LTC3375.
Summary of Features of the LTC3375:
- 8-Channel Independent Step-Down DC/DCs Master/Slave Configurable for Up to 4A per Output Rail with a Single Inductor
- Independent VIN Supply for Each DC/DC (2.25V to 5.5V)
- All DC/DCs Have 0.425V to VIN Output Voltage Range
- Precision Enable Pin Thresholds for Autonomous Sequencing (or I2C Control)
- 1MHz to 3MHz Programmable/Synchronizable Oscillator Frequency (2MHz Default)
- I2C Selectable Phasing (90° Steps) per Channel
- Programmable Power-On Reset/Watchdog/Pushbutton Timing
- Die Temperature Monitor Output
- 48-Lead 7mm × 7mm QFN Package
Typical Application
Applications
- General Purpose Multichannel Power Supplies
- Industrial/Automotive/Communications
About Linear Technology
Linear Technology Corporation, a manufacturer of high performance linear integrated circuits, was founded in 1981, became a public company in 1986 and joined the S&P 500 index of major public companies in 2000. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, µModule products, and many other analog functions. Applications for Linear Technology’s high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
Linear Technology (UK) Limited
Tel: +44 (0)1628 477066
E-mail: uksales@linear.com
Web site: www.linear.com
Website for product information: http://www.linear.com/product/LTC3375
