Datasheet
RoHS Compliance Information
| Size in Kbytes | Date |
 |
| LM138/LM338 5-Amp Adjustable Regulators |
396 Kbytes |
3-Mar-99 |
Download |
LM138/LM338 5-Amp Adjustable Regulators (Japanese)
 |
223 Kbytes |
|
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Package Availability, Models, Samples & Pricing
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) |
|
LM338T | SLM | 0 | 42786 | 0 | 0 | 3352500 | 2 | 951281028
|
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.
More Application Notes
| Title | Size in Kbytes |
Date |
|
| AN-74: Application Note 74 LM139/LM239/LM339 A Quad of Independently Functioning Comparators |
702 Kbytes |
1-Oct-02 |
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| AN-298: Application Note 298 Isolation Techniques for Signal Conditioning |
379 Kbytes |
2-Oct-02 |
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| AN-C: Application Note C V/F Converter ICs Handle Frequency-to-Voltage Needs |
187 Kbytes |
3-Oct-02 |
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| AN-286: Application Note 286 Applications of the LM392 Comparator Op Amp IC |
135 Kbytes |
2-Oct-02 |
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| AN-242: Application Note 242 Applying a New Precision Op Amp |
383 Kbytes |
4-Oct-04 |
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| AN-225: Application Note 225 IC Temperature Sensor Provides Thermocouple Cold-Junction Compensation |
89 Kbytes |
2-Oct-02 |
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| AN-275: Application Note 275 CMOS D/A Converters Match Most Microprocessors |
127 Kbytes |
2-May-04 |
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| AN-240: Application Note 240 Wide-Range Current-to-Frequency Converters |
126 Kbytes |
3-Oct-02 |
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| AN-272: Application Note 272 Op Amp Booster Designs |
382 Kbytes |
2-Oct-02 |
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| AN-295: Application Note 295 A High Performance Industrial Weighing System |
117 Kbytes |
4-Oct-04 |
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| AN-D: Application Note D Versatile Monolithic V/Fs can Compute as Well as Convert with High Accuracy |
248 Kbytes |
3-Oct-02 |
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| AN-285: Application Note 285 An Acoustic Transformer Powered Super‐High Isolation Amplifier |
172 Kbytes |
4-Oct-04 |
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| AN-288: Application Note 288 System-Oriented DC-DC Conversion Techniques |
405 Kbytes |
3-Oct-02 |
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| AN-247: Application Note 247 Using the ADC0808/ADC0809 8-Bit µP Compatible A/D Converters with 8-Channel Analog Multiplexer |
547 Kbytes |
3-Oct-02 |
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| AN-256: Application Note 256 Circuitry for Inexpensive Relative Humidity Measurement |
119 Kbytes |
2-Oct-02 |
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| AN-258: Application Note 258 Data Acquisition Using the ADC0816 and ADC0817 8-Bit A/D Converter with On-Chip 16 Channel Multiplexer |
683 Kbytes |
4-Oct-04 |
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| AN-673: 2-Way Multiplexed LCD Drive and Low Cost A/D-Converter Using V/F Techniques with COP8 Microcontrollers |
526 Kbytes |
5-Aug-95 |
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| AN-284: Application Note 284 Single-Supply Applications of CMOS MICRODACs |
121 Kbytes |
3-Oct-02 |
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| AN-274: Application Note 274 CMOS A/D Converter Interfaces Easily with Many Microprocessors |
73 Kbytes |
3-Oct-02 |
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| AN-210: Application Note 210 New Phase-Locked-Loops Have Advantages as Frequency to Voltage Converters (and more) |
339 Kbytes |
3-Oct-02 |
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| AN-265: Application Note 265 An Electronic Watt-Watt-Hour Meter |
185 Kbytes |
3-Oct-02 |
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| AN-301: Application Note 301 Signal Conditioning for Sophisticated Transducers |
579 Kbytes |
2-Oct-02 |
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[Information as of 4-Jul-2009]
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