LM338
Key Features
- Guaranteed 7 A peak output current
- Guaranteed 5 A output current )
- Adjustable output down to 1.2 V t(s
- Line regulation typically 0.005 %/V uc
- Load regulation typically 0.1 % d
- Guaranteed thermal regulation ro
- Current limit constant with temperature P
- Standard 3-lead transistor package oleteDescription bsThe LM138, LM238, LM338 are adjustable 3Oterminal positive voltage regulators capable of -supplying in excess of 5 A over a 1.2 V to 32 V )output range. They are exceptionally easy to use t(sand require only 2 resistors to set the output voltage. Careful circuit design has resulted in ucoutstanding load and line regulation parable dto many mercial power supplies. The LM138 rofamily is supplied in a standard 3-lead transistor Ppackage. teA unique feature of the LM138 family is time-delependent current limiting. The current limit circuitry oallows peak currents of up to 12 A to be drawn sfrom the regulator for short periods of time. This ballows the LM138 to be used with heavy transient Oloads and speeds start-up under full-load TO-3 protection remains functional even if the adjustment pin is accidentally disconnected. Normally, no capacitors are needed unless the device is situated far from the input filter capacitors in which case an input bypass is needed. An optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve.very high ripple rejection ratios which are difficult to achieve with standard 3-terminal regulators. Besides replacing fixed regulators or discrete designs, the LM238 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 input differential is not exceeded. The LM138, LM238, LM338 are packaged in standard steel TO-3 transistor package. The conditions. Under sustained loading conditions, LM138 is rated for operation from - 55 °C to the current limit decreases to a safe value 150 °C, the LM238 from - 25 °C to 150 °C and the protecting the regulator. Also included on the chip LM338 from 0 °C to 125 °C. are thermal overload protection and safe area protection for the power transistor. Overload Table
- Device summary Part numbers LM138 LM238 LM338 Order codes LM138K LM238K LM338K Temperature range -55 °C to 150 °C -25 °C to 150 °C 0 °C to 125 °C April 2008 Rev 2 1/23 .st. 23 Contents Contents
