LM338 - 5 Amp Adjustable Regulator

Datasheet Packaging Samples & Pricing Reliability Application Notes Knowledge Base

Features
Guaranteed 7A peak output current
Guaranteed 5A output current
Adjustable output down to 1.2V
Guaranteed thermal regulation
Current limit constant with temperature
P+ Product Enhancement tested
Output is short-circuit protected

General Description


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. More...


Applications


Adjustable power supplies
Constant current regulators
Battery chargers
  Typical Application
*click for larger image


Parametric Table     expand
Parametric Table    collapse
Output Current 5000 mA
Output Voltage Undefined Volt
Input Min Voltage 4.2 Volt
Input Max Voltage 40 Volt
Adjustable Output Yes
On/Off Pin No
Error Flag No
Temperature Min 0 deg C
Temperature Max 125 deg C
Special Features Undefined
Output Current 5000 mA
Output Voltage Undefined Volt
Input Min Voltage 4.2 Volt
Input Max Voltage 40 Volt
Adjustable Output Yes
On/Off Pin No
Error Flag No
Temperature Min 0 deg C
Temperature Max 125 deg C
Special Features Undefined
RegType Linear Regulator
Feedback Voltage 1.25 Volt
View Using Catalog


Typical Performance


*click for larger image


  Also Recommended
LM2677No Heatsink Required , On/off Pin
LM2678No Heatsink Required
LM2679No Heatsink Required , Adjustable Current Limit

Additional Resources


Application Notes (see below)


Connection Diagram


*click for larger image



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM138/LM338 5-Amp Adjustable Regulators 396 Kbytes 3-Mar-99 Download
LM138/LM338 5-Amp Adjustable Regulators (Japanese)
223 Kbytes   Download

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Package Availability, Models, Samples & Pricing
Part NumberPackageFactory Lead TimeModelsSamples &
Electronic
Orders
Budgetary PricingStd
Pack
Size
Package
Marking
Format
TypePinsSpec.MSL
Rating
Peak
Reflow
RoHS
Report
CAD
Symbols
WeeksQtyQty$US each
LM338TTO-2203STD
NOPB
1
1
NA
NA
RoHS N/A Full productionN/A
Samples
Buy Now
1K+$0.96rail
of
45
NSUZXYTTE#
LM338T P+
8 weeks1000
LM338K STEELTO-32STD
NOPB
1
1
NA
NA
RoHS N/A Full productionN/A
 
Buy Now
250+$32.20tray
of
50
NS
ZXYTTE#
LM338K
STEELP+
6 weeks500
LM338 MWCWaferFull productionN/A
  CALLwafer jar
of
N/A
-
N/A15000

General Description


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.

Reliability Metrics


Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM338TSLM0427860033525002951281028

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.


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[Information as of 4-Jul-2009]