Datasheet Linear Technology LTC3856

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Design Notes

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  2-Phase Synchronous Buck Controller Features Light Load Stage Shedding Mode, Active Voltage Positioning, Low RSENSE and Remote VOUT Sensing &mdash DN486
  PDF, 96 Kb, File published: Nov 10, 2010
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  2-Phase Synchronous Buck Controller Features Light Load Stage
  Shedding Mode, Active Voltage Positioning, Low RSENSE and
  Remote VOUT Sensing
  Design Note 486
  Charlie Zhao and Jian Li
  Introduction
  Today’s computer, datacom, and telecom systems demand power supplies that are efficient, respond quickly
  to load transients and accurately regulate the voltage
  at the load. For example, load current can be measured
  by using the inductor DCR, thus eliminating the need
  for a dedicated sense resistor. Inductor DCR sensing
  increases efficiency—especially at heavy load—while
  reducing component cost and required board space.
  The LTC В®3856 single-output 2-phase synchronous buck
  controller improves the accuracy of inductor DCR sensing
  by compensating for changes in DCR due to temperature. age sensing, Stage Sheddingв„ў mode for improved light
  load efficiency and adaptive voltage positioning for fast
  transient response. The LTC3856 can convert a wide input
  voltage range, 4.5V to 38V, to outputs from 0.6V to 5V.
  Despite the many features, the chip is small, available in
  32-pin 5mm Г— 5mm QFN and 38-pin TSSOP packages.
  High Efficiency, 2-Phase, 4.5V to 14V Input,
  1.5V/50A Output Converter …

Articles

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  2-Phase Synchronous Step-Down DC/DC Controller with Programmable Stage Shedding Mode and Active Voltage Positioning for High Efficiency and Fast Transient Response &mdash LT Journal
  PDF, 1.3 Mb, File published: Jun 30, 2010
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  design features 2-Phase Synchronous Step-Down DC/DC Controller with
  Programmable Stage Shedding Mode and Active Voltage
  Positioning for High Efficiency and Fast Transient Response
  Jian Li and Charlie Zhao The LTC3856 is a versatile and feature-rich single-output 2-phase synchronous buck
  controller with on-chip drivers, remote output voltage sensing, inductor DCR temperature
  compensation, Stage Sheddingв„ў mode and active voltage positioning (AVP). It is suitable for
  converting inputs of 4.5V–38V to outputs from 0.6V up to 5V. The LTC3856 facilitates the
  design of high efficiency, high power density solutions for telecom and datacom systems,
  industrial and medical instruments, DC power distribution systems and computer systems.
  The controller is available in 32-pin 5mm Г— 5mm QFN and 38-pin TSSOP packages.
  MAJOR FEATURES making it possible to produce a large stepdown ratio applications in very little space. The LTC3856’s constant-frequency peak
  current-mode control architecture allows
  a phase-lockable frequency of up to
  770kHz. For high frequency applications,
  the LTC3856 can operate at low duty cycles
  due to its small minimum on-time (90ns), drops during heavy load conditions.
  Figure 1 shows a typical 4.5V~14V input,
  1.5V/50A output application schematic. The LTC3856 includes a high speed differential amplifier for remote output
  voltage sensing, which can eliminate
  the regulation error due to PCB voltage The LTC3856’s two channels operate
  anti-phase, which reduces the input
  RMS current ripple and thus the input Figure 1. A 1.5V/50A, 2-phase converter featuring the LTC3856
  VIN + VIN 1nF 0.1ВµF 2.2О© S 5.6k 100pF 100О© VIN 100О© …

Model Line

Manufacturer's Classification

• Power Management > Switching Regulator > Step-Down (Buck) Regulators > External Power Switch Buck Controllers