Datasheet Linear Technology LTC3708

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  Dual Output DC/DC Converter Solutions for Xilinx FPGA Based Systems &mdash Design Solutions 41
  PDF, 183 Kb, File published: Feb 1, 2004
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  Design Solutions 41
  February 2004
  Dual Output DC/DC Converter Solutions
  for Xilinx FPGA Based Systems
  Charlie Zhao
  INTRODUCTION
  Xilinx FPGAs require at least two power supplies: VCCINT
  for core circuitry and VCCO for I/O interface. For the latest
  Xilinx FPGAs, including Virtex-II Pro, Virtex-II and Spartan-3, a third auxiliary supply, VCCAUX may be needed. In
  most cases, VCCAUX can share a power supply with VCCO.
  The core voltages, VCCINT, for most Xilinx FPGAs, range
  from 1.2V to 2.5V. Some mature products have 3V, 3.3V
  or 5V core voltages. Table 1 shows the core voltage
  requirement for most of the FPGA device families. Typical
  I/O voltages (VCCO) vary from 1.2V to 3.3V. The auxiliary
  voltage VCCAUX is 2.5V for Virtex-II Pro and Spartan-3, and
  is 3.3V for Virtex-II.
  Each FPGA family has a specific quiescent supply current,
  ranging from under 100mA to about 2A. For applications
  with multiple FPGAs, the core supply current can be higher
  than 10A.
  With multiple voltage rails in today’s systems (FPGA, DDR
  memory, data converter ICs, etc.), supply sequencing and …

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  High Performance Switch Mode Power Solutions for Altera Low Voltage FPGAs &mdash Design Solutions 43
  PDF, 158 Kb, File published: Jun 1, 2004
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  Design Solutions 43
  June 2004
  High Performance Switch Mode Power Solutions
  for Altera Low Voltage FPGAs
  by Mike Shriver
  INTRODUCTION
  The core voltages for FPGAs are moving lower as a result
  of advances in the fabrication process. The newest FPGA
  family from Altera, the StratixВ® II, now requires a core
  voltage of 1.2V and the Stratix, Stratix GX, HardCopyВ®
  Stratix and CycloneTM families require a core voltage of
  1.5V. This article discusses how to power the core and I/O
  of low voltage FPGAs using the latest step-down switch
  mode controllers from Linear Technology Corporation.
  To ensure correct selection of power management circuitry,
  it is recommended to use Altera’s PowerPlay Power Estimation Tools to obtain accurate results. Tools are available
  to help determine power consumption before and during
  the design process. More information on these tools is
  available from Altera’s website: http://www.altera.com/
  support/devices/estimator/pow-powerplay.html.
  Overview
  The load and input voltage requirements for FPGA systems vary considerably. A single FPGA typically requires
  less than 2A, but for systems using multiple FPGAs, the …

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  2-Phase DC/DC Controller Makes Fast, Efficient and Compact Power Supplies &mdash DN334
  PDF, 101 Kb, File published: Apr 1, 2004
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  advertisement 2-Phase DC/DC Controller Makes Fast, Efficient and Compact
  Power Supplies – Design Note 334
  David Chen
  High efficiency, fast transient response and small size
  are often at odds in power supply designs. Fortunately,
  the 2-phase LTC В®3708 PWM controller makes it possible to simultaneously achieve all three. Figure 1 shows
  the LTC3708 in a compact, high efficiency dual-output
  power supply that has excellent transient response.
  VIN
  3.3V TO 28V CIN
  10ОјF
  35V w4 The device uses a combination of design features to
  make all of this possible. High efficiency is attained
  through a combination of features: a No RSENSEв„ў current
  sensing technique, 2-phase operation mode, onboard
  L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks
  and No RSENSE is a trademark of Linear Technology Corporation. All other
  trademarks are the property of their respective owners. CMDSH-3 L1
  2.2ОјH VOUT1
  2.5V
  5A COUT1 +
  220ОјF
  4V …

Articles

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  2-Phase Controller Makes Small, Fast and Efficient Power Supplies with Output Tracking &mdash LT Journal
  PDF, 209 Kb, File published: Feb 1, 2004
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  DESIGN FEATURES 2-Phase Controller Makes Small,
  Fast and Efficient Power Supplies
  by David Chen
  with Output Tracking
  Introduction
  High efficiency, small size and fast
  transient response are often at odds
  in power supply designs. It is generally
  accepted that any one power supply
  design can achieve, at best, two of these
  at the expense of the third. This is no
  longer true. The LTC3708 2-phase
  PWM controller makes it possible to
  simultaneously achieve all three by offering a unique set of powerful features
  (summarized in Table 1).
  The LTC3708 is a dual-output,
  synchronous step-down DC/DC
  controller. It uses a constant on-time,
  valley-current control architecture to
  regulate each output independently.
  The on-time of the first output channel
  is programmed by an external resistor so that the switching frequency
  is kept relatively constant over input …

Model Line

Manufacturer's Classification

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