Datasheet Linear Technology LTC1478

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LTC1477

Design Notes

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  70mOhm Protected Load Management Switch &mdash DN117
  PDF, 125 Kb, File published: Nov 1, 1995
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  advertisement 70mΩ Protected Load Management Switch – Design Note 117
  Mitchell Lee and Tim Skovmand
  In an effort to conserve energy, simple shutdown schemes
  are incorporated into many battery-operated circuits. Not
  all circuits lend themselves to direct control, however, and
  instead the supply must be turned off by a switch. The
  LTC В®1477 high side switch is designed for this purpose
  and includes short-circuit current limit and thermal shutdown to guard against faulty loads. Figure 1 shows a
  simplified block diagram of the LTC1477.
  VIN V+
  D1 D2 D3 CHARGE
  PUMP
  ENABLE LTC1477
  S2 VOUT Figure 2 shows the LTC1477 and LTC699 conjoined in an
  undervoltage disconnect application. The LTC699 microprocessor supervisor disables the LTC1477 and hence the
  load whenever the input voltage falls below 4.65V. An
  external logic signal applied to the gate of Q1 can also
  disable the LTC1477. When enabled, the LTC1477 output
  ramps over a period of approximately 1ms, thereby limiting
  the peak current in the load capacitor to 500mA. This
  prevents glitches on the 5V source line that might otherwise affect adjacent loads.
  An LT В®1301 is used in Figure 3 to boost a 3.3V or 5V input
  to 12V, such as VPP for Flash memory. Although the …

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Manufacturer's Classification

• Monitor, Control and Protection > High Side Switches & MOSFET Drivers