LM317LMX Linear Voltage Regulator IC Equivalent & Substitute Parts

Part Overview

The LM317LMX is a positive adjustable linear voltage regulator IC manufactured by Texas Instruments, designed for applications requiring adjustable output voltage regulation up to 100mA. This device operates across an input voltage range of up to 40V and provides output voltage adjustment from 1.2V to 37V. The LM317LMX is classified as Last Time Buy, indicating discontinued production status. Finding equivalent and substitute parts is necessary to ensure design continuity and maintain supply chain reliability for new production runs and long-term support.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM317LMX
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Output Configuration	Positive
Output Type	Adjustable
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	1.2V
Voltage - Output (Max)	37V
Current - Output	100mA
Operating Temperature	-40°C ~ 125°C
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the LM317LMX are qualified based on the following critical parameters that determine functional and mechanical compatibility:

Electrical Parameters:

Output Configuration: Positive
Output Type: Adjustable
Voltage - Input (Max): 40V
Voltage - Output (Min/Fixed): 1.2V
Voltage - Output (Max): 37V
Current - Output: 100mA
Operating Temperature Range: -40°C ~ 125°C (or compatible subset)
Protection Features: Over Current, Over Temperature, Short Circuit

Mechanical Parameters:

Package / Case: 8-SOIC (0.154", 3.90mm Width)
Mounting Type: Surface Mount
Supplier Device Package: 8-SOIC

Compliance Parameters:

RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level (MSL): 1 (Unlimited)

Substitute parts meeting all electrical, mechanical, and compliance criteria are classified as direct equivalents. Parts with minor variations in quiescent current (Iq) or PSRR specifications remain functionally compatible within the same application envelope.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Product Status	Voltage - Input (Max)	Voltage - Output (Min/Fixed)	Voltage - Output (Max)	Current - Output	Current - Quiescent (Iq)	Operating Temperature	Package / Case	Protection Features
LM317LMX	Texas Instruments	Last Time Buy	40V	1.2V	37V	100mA	5 mA	-40°C ~ 125°C	8-SOIC	Over Current, Over Temperature, Short Circuit
LM317LMX/NOPB	Texas Instruments	Active	40V	1.2V	37V	100mA	5 mA	-40°C ~ 125°C	8-SOIC	Over Current, Over Temperature, Short Circuit
LM317LD13TR	STMicroelectronics	Active	40V	1.2V	37V	100mA	5 mA	0°C ~ 125°C	8-SOIC	Over Current, Over Temperature, Short Circuit
LM217LD13TR	STMicroelectronics	Active	40V	1.2V	37V	100mA	Not specified	-40°C ~ 125°C	8-SOIC	Over Temperature, Short Circuit
LM317LDR2G	onsemi	Active	40V	1.2V	37V	100mA	10 mA	0°C ~ 125°C	8-SOIC	Over Current, Over Temperature, Short Circuit
LM317LBDR2G	onsemi	Active	40V	1.2V	37V	100mA	10 mA	-40°C ~ 125°C	8-SOIC	Over Current, Over Temperature, Short Circuit
NCV317LBDR2G	onsemi	Active	40V	1.2V	37V	100mA	10 mA	-40°C ~ 125°C	8-SOIC	Over Current, Over Temperature, Short Circuit

Engineering Selection Recommendations

Primary Recommendation: LM317LMX/NOPB (Texas Instruments)

The LM317LMX/NOPB is the direct equivalent to the LM317LMX with identical electrical specifications and active product status. This part maintains full compatibility with existing designs and offers the highest inventory availability (870,100 pcs). Selection of this part eliminates any design modification requirements.

Secondary Recommendation: LM317LBDR2G (onsemi)

The LM317LBDR2G provides full parametric equivalence with the original LM317LMX, including the extended operating temperature range (-40°C ~ 125°C) and identical protection features. The quiescent current specification (10 mA vs. 5 mA) represents a minor increase that does not impact functional compatibility in standard applications. This part is actively produced with substantial inventory (885,200 pcs).

Alternative Recommendation: LM317LD13TR (STMicroelectronics)

The LM317LD13TR is an active product with identical electrical specifications except for the operating temperature range (0°C ~ 125°C vs. -40°C ~ 125°C). This part is suitable for applications not requiring extended low-temperature operation. Inventory availability is excellent (886,524 pcs).

Automotive Grade Option: NCV317LBDR2G (onsemi)

The NCV317LBDR2G is qualified to AEC-Q100 automotive standards and provides full electrical equivalence with extended temperature range. This part is specified for automotive applications requiring automotive-grade components.

Note on LM217LD13TR (STMicroelectronics)

The LM217LD13TR lacks Over Current protection compared to the original LM317LMX. This part is suitable only for applications where Over Current protection is not required or is provided externally.

Frequently Asked Questions (FAQ)

Q: Can I use LM317LMX/NOPB as a direct replacement for LM317LMX?

A: Yes. The LM317LMX/NOPB is electrically and mechanically identical to the LM317LMX. The "/NOPB" designation indicates lead-free plating and represents the current production variant. No design changes are required.

Q: What is the difference between LM317LBDR2G and LM317LDR2G?

A: Both parts are manufactured by onsemi and share identical electrical specifications. The primary difference is the operating temperature range: LM317LBDR2G operates from -40°C ~ 125°C, while LM317LDR2G operates from 0°C ~ 125°C. Select LM317LBDR2G for applications requiring extended low-temperature operation.

Q: Why does LM317LD13TR have a narrower temperature range?

A: The LM317LD13TR is specified by STMicroelectronics with an operating range of 0°C ~ 125°C. This represents the manufacturer's tested and guaranteed performance window. Applications requiring operation below 0°C must use parts with extended low-temperature ratings such as LM317LMX/NOPB or LM317LBDR2G.

Q: Is the quiescent current difference between parts significant?

A: The LM317LMX and LM317LD13TR specify 5 mA quiescent current, while onsemi parts (LM317LDR2G, LM317LBDR2G, NCV317LBDR2G) specify 10 mA. This 5 mA difference is negligible in most applications and does not affect functional compatibility. For battery-powered or ultra-low-power applications, verify that the higher quiescent current meets design requirements.

Q: Can I use NCV317LBDR2G in non-automotive applications?

A: Yes. The NCV317LBDR2G meets all electrical and mechanical requirements for standard applications. The automotive qualification (AEC-Q100) represents additional testing and reliability assurance, not a restriction on use. This part is suitable for any application requiring the LM317 function.

Q: Are all substitute parts in the same 8-SOIC package?

A: Yes. All listed substitute parts use the 8-SOIC (0.154", 3.90mm Width) package. No PCB layout modifications are required when switching between these parts.

Q: What should I consider when selecting between Texas Instruments and onsemi alternatives?

A: Both manufacturers provide active products with full compliance. Selection should be based on: (1) operating temperature requirements, (2) quiescent current specifications for your application, (3) inventory availability, and (4) existing supply chain relationships. All parts meet RoHS3 and MSL requirements.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message