8 Detailed Description

8.1 Overview

The LM117QML-SP 3-terminal positive voltage linear regulator is capable of supplying either 0.5 A or 1.5 A over

a 1.2-V to 37-V output range. It is simple to use and requires only two external resistors to set the output voltage.

Further, both line and load regulation are better than standard fixed regulators.

The regulator is "floating" and sees only the input-to-output differential voltage, thus enabling supplies of several

hundred volts to be regulated as long as the maximum input-to-output differential is not exceeded (i.e. don’t short

circuit the output).

The LM117QML-SP offers full overload protection such as current limit, thermal overload protection, and safe

area protection. All overload protection circuitry remains fully functional even if the adjustment terminal is

disconnected.

Typically, no capacitors are needed unless the device is situated more than 6 in 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.

This device makes an especially simple adjustable switching regulator, a programmable output regulator, or

by connecting a fixed resistor between the adjustment pin and output it can be used as a precision current

regulator. Supplies with electronic shutdown can be achieved by clamping the adjustment terminal to ground

which programs the output to 1.2 V where most loads draw little current.

8.2 Functional Block Diagram

+

±

+

±

+

±

Pro tection

Circuitr y

ADJ

OUT

IN

ìXí Q

Figure 8-1. Functional Block Diagram

www.ti.com

LM117QML-SP

SNVSC12 – APRIL 2021

Copyright © 2021 Texas Instruments Incorporated

Submit Document Feedback

13

Product Folder Links: LM117QML-SP