Datasheet Linear Technology LTC1645

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Design Notes

• Download
  LTC1645 Dual Channel Hot Swap Controller/Power Sequencer
  Allows Insertion Into a Live Backplane &mdash DN217
  PDF, 81 Kb, File published: Nov 1, 1999
  Extract from the document

  Dual Channel Hot Swap Controller/Power Sequencer Allows
  Insertion Into a Live Backplane – Design Note 217
  Bill Poucher
  The LTC В®1645 is a two-channel Hot Swapв„ў controller
  and power sequencer that allows a board to be safely
  inserted and removed from a live backplane. When a
  board is hot swapped, the supply bypass capacitors on
  the board can draw huge transient currents from the
  backplane power bus as they charge. These transient
  currents can cause permanent damage to the capacitors, connector pins and board traces and can disrupt
  the system supply, causing other boards in the system
  to reset. well as a timer pin to create a delay before ramping up
  the supply voltages and before deasserting the system
  reset signal.
  Basic Operation
  The LTC1645 controls a board’s power supplies with
  external N-channel pass transistors in the power paths
  as shown in Figure 1 and Figure 3. The LTC1645 contains
  an internal charge pump to provide high side drive to the
  N-channel FETs. RSENSE1 and RSENSE2 provide current
  fault detection, and R1 and R2 prevent high frequency
  oscillation. By ramping the gates of the pass transistors
  up and down at a controlled rate, the transient surge …

• Download
  PCI Express Power and Mini Card Solutions &mdash DN346
  PDF, 79 Kb, File published: Sep 3, 2004
  Extract from the document

  PCI Express Power and Mini Card Solutions – Design Note 346
  Mitchell Lee and Vladimir Ostrerov
  Introduction
  PCI Express is the third generation of PCI (Peripheral
  Component Interconnect) technology used to connect
  I/O perhipheral devices in computer systems. It is
  intended as a general purpose I/O device interconnect
  that meets the needs of a wide variety of computing
  platforms such as desktop, mobile, server and communications. It also specifies the electrical and mechanical
  attributes of the backplane, connectors and removable
  cards in these systems. PCI Express Mini Card also provides two power sources:
  3.3V and 1.5V. The auxiliary voltage (3.3VAUX) is sourced
  over the same pins as the primary 3.3V supply and is
  available during the standby/suspend state to support
  wake-event processing on the Mini Card. Table 2 summarizes PCI Express Mini Card power specifications. Power Requirements
  Each add-in card connector requires two power rails:
  12V and 3.3V, along with a third, optional 3.3V auxiliary rail. If the designer elects to provide the auxiliary
  3.3V rail in his system or if the platform supports the
  WAKE# signal, the 3.3VAUX rail must be supplied to all
  connectors. Table 2. Summary of PCI Express Mini Card Supply
  Requirements In PCI Express, as in PCI, the Hot Swapв„ў controller is
  resident on the platform side of the system, delivering
  power to the connectors only after a card is inserted. …

Articles

• Download
  LTC1645/LTC1735 Circuit Solves PCI Power Problem &mdash LT Journal
  PDF, 232 Kb, File published: Feb 1, 2000
  Extract from the document

  DESIGN IDEAS LTC1645/LTC1735 Circuit Solves
  PCI Power Problem
  by Ajmal Godil
  to plugging a circuit board into or
  removing it from a live backplane.
  When this is done, the supply bypass
  capacitors on the board can draw
  huge transient currents from the
  backplane power bus as they charge.
  The transient currents can cause permanent damage to the connector pins In some applications, it is necessary to select and hot swap the higher
  of two supplies and generate a regulated output voltage from the selected
  supply. If only one input supply is
  present, the circuit should select it
  and generate the same output voltage. The term “hot swapping” refers Q1-A
  1/2 Si4936 VIN1
  5V
  R1
  10k D1
  MBR0520 Q3-A
  1/2 Si4936 VIN2
  3.3V and cause glitches on the system
  supply, causing other boards in the
  system to reset. A circuit based on an …

• Download
  Versatile Dual Hot Swap Controller/Power Sequencer Allows Live Backplane Insertion &mdash LT Journal
  PDF, 178 Kb, File published: Nov 1, 1999
  Extract from the document

  DESIGN FEATURES Versatile Dual Hot Swap Controller/
  Power Sequencer Allows
  by Bill Poucher
  Live Backplane Insertion
  Introduction
  When a circuit board is inserted into
  a live backplane, the supply bypass
  capacitors on the board can draw
  large transient currents from the
  backplane power bus as they charge.
  These transient currents can destroy
  capacitors, connector pins and board
  traces and can disrupt the system
  supply, causing other boards in the
  system to reset. The new dual-channel LTC1645 Hot Swap controller is
  designed to ramp a circuit board’s
  supply voltages in a controlled manner, preventing glitches on the system
  supply and damage to the board.
  The LTC1645’s two channels can
  be set to ramp up and down separately, or they can be programmed to
  rise and fall simultaneously, ensuring power supply tracking at the two
  outputs. Using external N-channel
  pass transistors, the supply voltages …

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Manufacturer's Classification

• Monitor, Control and Protection > Hot Swap Controllers > Low Voltage Hot Swap Controllers