The LM317M is an adjustable 3-terminal positive voltage regulator capable of supplying more than 500-mA over an output-voltage range of 1.25-V to
37-V. The LM317M is exceptionally easy to use and requires only two external resistors to set the output. Furthermore, both line and load regulation are better than standard fixed regulators.
In addition to having higher performance than fixed regulators, the LM317M includes on-chip current limiting, thermal-overload protection, and safe- operating-area protection. All overload protection remains fully functional if the ADJUST terminal is disconnected.
The LM317 is a floating regulator meaning there is no device ground terminal. Quiescent current flows to the load instead of being wasted flowing to ground. Regulated output voltage of hundreds of volts is possible if the maximum input to output differential does not exceed 40-V at any time. Device can be used as a floating current source controlled by a single resistor.
Normally, no capacitors are needed unless the device is more than six inches from the input filter capacitors, in which case an input bypass capacitor of any type is needed. An optional electrolytic or tantalum output capacitor can be added to improve transient response. Ceramic output capacitors can be used but output ringing may be present on transients. The ADJUST terminal can be bypassed with any type of capacitor to achieve high ripple-rejection ratios, which are difficult to achieve with standard three-terminal regulators.
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | LM317M 3-Terminal Adjustable Regulator datasheet (Rev. P) | 31 Mar 2014 | |
| Application note | LDO Noise Demystified (Rev. B) | PDF | HTML | 18 Aug 2020 | |
| Application note | LDO PSRR Measurement Simplified (Rev. A) | PDF | HTML | 09 Aug 2017 | |
| Application note | Method For Cal Output Voltage Tolerances in Adj Regs (Rev. A) | 05 May 2013 | ||
| Application note | A New Production Technique for Trimming Voltage Regulators | 03 Oct 2002 | ||
| Application note | Adjustable 3-Terminal Regulator for Low-Cost Battery Charging Systems | 03 Oct 2002 |
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The MLTLDO2EVM-037 multipackage low-dropout (LDO) evaluation module (EVM) allows design engineers to evaluate the operation and performance of several common packages of linear regulators for possible use in their own circuit application. This EVM configuration contains a DDA, 3-pin and 5-pin KVU, (...)
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| SOT-223 (DCY) | 4 | Ultra Librarian |
| TO-252 (KVU) | 3 | Ultra Librarian |
Recommended products may have parameters, evaluation modules or reference designs related to this TI product.
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