DC/DC Controller features differential remote sensing.
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Press Release Summary:
Operating with N-channel MOSFETs from 4.5-38 V input, 2-phase Model LTC3856 can produce ±0.75% accurate output voltages from 0.6-5 V with efficiency up to 95%. Up to 12 phases can be paralleled and clocked out of phase to minimize I/O filtering requirements. Differential amplifier provides remote output voltage sensing of positive and negative terminals, while adjustable Stage Shedding(TM) increases efficiency at light loads by eliminating gate charge and switching losses of one output stage.
Original Press Release:
High Power Multiphase Step-Down DC/DC Controller Features Differential Remote Sensing, Active Voltage Positioning & Stage Shedding Technology
MILPITAS, CA - - Linear Technology Corporation introduces the LTC3856, a two-phase single output high efficiency (up to 95%) synchronous step-down DC/DC controller with PolyPhase® operation, differential output voltage sensing and integrated phased-lock loop (PLL) synchronization. Up to 12 phases can be paralleled and clocked out of phase to minimize input and output filtering requirements for high current applications (up to 300A). The differential amplifier provides remote output voltage sensing of both the positive and negative terminals, enabling high accuracy regulation independent of IR losses in trace runs, vias and interconnects. Applications include high current ASIC and FPGA supplies, power distribution buses, high power audio amplifiers and network servers.
The LTC3856 operates with all N-channel MOSFETs from input voltages ranging from 4.5V to 38V and it can produce ±0.75% accurate output voltages from 0.6V to 5V. The output current is sensed by monitoring the voltage drop across the output inductor (DCR) or by using a sense resistor. Programmable DCR temperature compensation maintains an accurate and constant current limit set point over a broad temperature range. The powerful onboard gate drivers minimize MOSFET switching losses and enable the use of multiple MOSFETs connected in parallel. A fixed operating frequency can be programmed from 250kHz to 770kHz or can be synchronized to an external clock with its internal PLL. The device's minimum on-time of just 90ns makes the LTC3856 ideal for high step-down ratio applications.
The LTC3856 incorporates an adjustable Stage Shedding(TM) technique to increase efficiency at light loads by eliminating gate charge and switching losses of one of its output stages. In addition, the LTC3856 can be configured for adjustable Burst Mode® operation to produce even higher efficiency at light loads. Its adaptive voltage positioning (AVP) minimizes the maximum transient voltage deviation during a load current step.
Tracking and sequencing functions allow the optimization of power-up and power-down of multiple power supplies. Additional features include current mode control, an onboard LDO for IC power, programmable soft start, a power good output and external VCC control.
The LTC3856 is available in thermally enhanced 38-lead SSOP or 32-lead 5mm x 5mm QFN packages and operates over a -40ºC to 125ºC operating junction temperature range. 1000-piece price starts at $3.12 each. Both versions are available from stock. For more information, visit www.linear.com/pr/3856.
Summary Features LTC3856
Multiphase Operation - Up to 12 Phases
High Efficiency - Up to 95%
Adjustable Stage Shedding(TM) Technique
Programmable Burst Mode® Operation
Wide VIN Range from 4.5V to 38V
VOUT Ranging from 0.6V to 5V, ±0.75% Accuracy
True Differential Amplifier for Remote Output Voltage Sensing
RSENSE or DCR Current Sensing
Programmable DCR Temperature Compensation
Powerful Onboard N-Channel MOSFET Gate Drivers
Adaptive Voltage Positioning
Output Voltage Tracking or Programmable Soft Start
Phase-Lockable Fixed Frequency from 250kHz to 770kHz
Current Mode Control for Accurate & Easy Current Sharing
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.
LT, LTC, LTM, µModule, Burst Mode, PolyPhase and are registered trademarks and Stage Shedding is a trademark of Linear Technology Corp. All other trademarks are the property of their respective owners.
North America and General Information
John Hamburger
Tel: (408) 432-1900 ext. 2419
jhamburger@linear.com
Doug Dickinson
Tel: (408) 432 1900 ext. 2233
ddickinson@linear.com
