Customer Login
If you are already registered, please log in.
Zoom the image with the mouse
The LM138 series of adjustable 3-terminal positive
voltage regulators is capable of supplying in excess
of 5 A over a 1.2-V to 32-V 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 12 A 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 (ADJ) 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 increases the ripple rejection of the regulator.
Besides replacing fixed regulators or discrete
designs, the LM138 is useful in a wide variety of
other applications. Because the regulator is floating
and receives 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; 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-CAN package, while those with a T suffix
are packaged in a TO-220 plastic package. The
LM138 is rated for TJ = –55°C to 150°C, and the
LM338 is rated for TJ = 0°C to 125°C
Package Included:
10 x LM338T LM338 Adjustable Regulator 5A 1.2V To 32V TO-220
You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
If you are already registered, please log in.