9

LM317HV-MIL

www.ti.com

SNVSAY1 – JUNE 2017

Product Folder Links: LM317HV-MIL

Submit Documentation Feedback

Copyright © 2017, Texas Instruments Incorporated

7.3 Feature Description

7.3.1 Load Regulation

The LM317HV-MIL is capable of providing extremely good load regulation but a few precautions are needed to

obtain maximum performance. The current set resistor, R1, should be connected near the output terminal of the

regulator rather than near the load. If R1 is placed too far from the output terminal, then the increased trace

regulation performance.

Figure 14. Regulator With Line Resistance in Output Lead

With the TO-3 package, it is easy to minimize the resistance from the case to the set resistor, by using two

separate leads to the case. However, with the TO-39 package, take care to minimize the wire length of the

output lead. The ground of R2 can be returned near the ground of the load to provide remote ground sensing

and improve load regulation.

7.3.2 Current Limit

Internal current limit will be activated whenever the output current exceeds the limit indicated in Typical

Characteristics. However, if the regulators differential voltage exceeds the absolute maximum rating of 60 V

down and the device may be damaged or fail. Failure modes range from an apparent open or short from input to

output of the regulator, to a destroyed package (most common with the TO-220 package). To protect the

regulator, the user is advised to be aware of voltages that may be applied to the regulator during fault conditions

and to avoid violating the Absolute Maximum Ratings.

7.4 Device Functional Modes

7.4.1 External Capacitors

An input bypass capacitor is recommended. A 0.1-μF disc or 1-μF solid tantalum on the input is suitable input

bypassing for almost all applications. The device is more sensitive to the absence of input bypassing when

adjustment or output capacitors are used but the above values will eliminate the possibility of problems.

The adjustment terminal can be bypassed to ground on the LM317HV-MIL to improve ripple rejection. This

bypass capacitor prevents ripple from being amplified as the output voltage is increased. With a 10-μF bypass

capacitor the 80-dB ripple rejection is obtainable at any output level. Increases over 10 μF do not appreciably

improve the ripple rejection at frequencies above 120 Hz. If the bypass capacitor is used, it is sometimes

necessary to include protection diodes to prevent the capacitor from discharging through internal low current

paths and damaging the device.