LM338 Regulator: Circuit, Price and Pinout

LM338 is a three terminal positive adjustable voltage regulator IC available in TO-220 package. It provides stable output voltage for example if the user set its output on 5V then it will provide stable 5V output no matter if the input voltage is fluctuating. But the user or designer of the circuit has to keep one more thing in mind that the input voltage must be 2V to 3V higher than the output voltage in any condition. 

In order to solve this problem the user should provide higher input voltage than the output for example for 5V output the input voltage can be 12V or more so if the input voltage fluctuates 3V to 5V then we still get a stable 5V at the output. One best example of this can be a solar panel that changes the output voltage frequently on a partly cloudy day.

This IC is adjustable from 1.2V to 32V DC and the maximum input voltage can be applied to the IC is 40V. LM338 can be easily used in the place of LM317 if there is a requirement for higher amperes, it is capable to deliver load of up to 5A output current. However, this can also be done by using one or two high current transistors with the LM317 IC but using LM388 is still a good option if the output current requirement is under 5A.

Moreover LM338 requires very low external components because all the important circuitry is built inside the IC and hence at the output it requires only two capacitors (in some conditions), and two external resistors to adjust the output voltage. There is also an output voltage calculator available online for the IC which shows the value of the resistor to be used for a specific output.

Symbol

Footprint

3D Model

-Available in 3 lead transistor TO-220 package

-Guaranteed 5A output current

-Guaranteed 7A peak output current

-Voltage adjustable from 1.2V to 32V

-Less external components required

-Only two external resistors are required for output adjustment.

-Short circuit protection capability

-Overheat shutdown functionality

-Reliable to use in commercial applications

-Maximum input voltage is 40V DC

-Low standby current

-Low price

-Adjustable output down to 1.2V

-Guaranteed thermal regulation

-Current limit constant with temperature

-P+ Product Enhancement tested

-Line regulation typically 0.005 %/V

-Load regulation typically 0.1 %

Texas Instruments LM338T/NOPB technical specifications, attributes, parameters and parts with similar specifications to Texas Instruments LM338T/NOPB.

-Used in commercial power supplies

-Used in educational power supplies

-Used in lab power supplies

-Used in voltage step down circuits

-Used in battery chargers circuits

-Used in solar power supplies

-Used in solar battery charger circuits

-Used in microcontroller Applications

-Used in DC to DC converters Circuits

-Used in portable Instrument applications

-Used in adjustable power supplies

-Used in constant current regulators

Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globally.[6] It is one of the top 10 semiconductor companies worldwide based on sales volume.The company's focus is on developing analog chips and embedded processors, which account for more than 80% of its revenue.TI also produces TI digital light processing technology and education technology products including calculators, microcontrollers and multi-core processors. The company holds 45,000 patents worldwide as of 2016.

Download datasheets and manufacturer documentation for Texas Instruments LM338T/NOPB.