The LM117 series of adjustable 3-terminal positive voltage regulators is capable of supplying in excess of 1.5A over a 1.2V to 37V output range. They are exceptionally easy to use and require only two external resistors to set the output voltage. Further, both line and load regulation are better than standard fixed regulators. Also, the LM117 is packaged in standard transistor packages which are easily mounted and handled. In addition to higher performance than fixed regulators, the LM117 series offers full overload protection available only in IC's. Included on the chip are current limit, thermal overload protection and safe area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is 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 optional output capacitor can be added to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection ratios which are difficult to achieve with standard 3-terminal regulators. Besides replacing fixed regulators, the LM117 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 differential voltage is not exceeded.
The LM117 series are 3‑terminal adjustable positive voltage regulators that provide up to 1.5 A over a 1.2 V to 37 V output range. They require only two external resistors to set the output voltage and include built‑in current limit, thermal overload and safe‑area protection.
The document lists electrical characteristics, package options, ordering information and absolute maximum ratings for the LM117, LM317A and LM317 devices, along with typical application notes and connection diagrams.
| Output voltage tolerance (LM317A) | ±1 % |
|---|---|
| Line regulation (LM317A) | max 0.01 %/V |
| Load regulation (LM117) | max 0.3 % |
| Maximum output current | 1.5 A |
| Ripple rejection | 80 dB |
| Operating temperature (LM117) | -55 °C to +150 °C |
The LM117 series can deliver up to 1.5 A of output current.
They include current limit, thermal overload protection and safe‑area protection.
The device offers 80 dB of ripple rejection.