lm338应用电路

lm338应用电路
  
  The LM138 series of adjustable 3-terminal positive voltage
  regulators is capable of supplying in excess of 5A over a
  1.2V to 32V output range. They are exceptionally easy to
  use and require only 2 resistors to set the output voltage.
  Careful circuit design has resulted in outstanding load and
  line regulation—comparable to many commercial power
  supplies. The LM138 family is supplied in a standard 3-lead
  transistor package.
  A unique feature of the LM138 family is time-dependent current
  limiting. The current limit circuitry allows peak currents
  of up to 12A to be drawn from the regulator for short periods
  of time. This allows the LM138 to be used with heavy transient
  loads and speeds start-up under full-load conditions.
  Under sustained loading conditions, the current limit decreases
  to a safe value protecting the regulator. Also included
  on the chip are thermal overload protection and safe
  area protection for the power transistor. Overload protection
  remains functional even if the adjustment pin is accidentally
  disconnected.
  Normally, no capacitors are needed unless the device is situated
  more than 6 inches from the input filter capacitors in
  which case an input bypass is needed. An output capacitor
  can be added to improve transient response, while bypassing
  the adjustment pin will increase the regulator’s ripple rejection.
  Besides replacing fixed regulators or discrete designs, the
  LM138 is useful in a wide variety of other applications. Since
  the regulator is “floating” and sees only the input-to-output
  differential voltage, supplies of several hundred volts can be
  regulated as long as the maximum input to output differential
  is not exceeded, i.e., do not short-circuit output to ground.
  The part numbers in the LM138 series which have a K suffix
  are packaged in a standard Steel TO-3 package, while those
  with a T suffix are packaged in a TO-220 plastic package.
  The LM138 is rated for ?55°C £ TJ £ +150°C, and the LM338
  is rated for 0°C £ TJ £ +125°C.
  Features
  n Guaranteed 7A peak output current
  n Guaranteed 5A output current
  n Adjustable output down to 1.2V
  n Guaranteed thermal regulation
  n Current limit constant with temperature
  n P+ Product Enhancement tested
  n Output is short-circuit protected
  Applications
  n Adjustable power supplies
  n Constant current regulators
  n Battery chargers
  LM138/LM338 pdf datasheet (5-Amp Adjustable Regulators)