LM317T Linear Voltage Regulator IC Equivalent & Substitute Parts

Part Overview

The LM317T is a positive adjustable linear voltage regulator IC manufactured by Texas Instruments, rated for 1.5A output current in a TO-220-3 package. This device is classified as Last Time Buy, indicating limited availability from the original manufacturer. Finding equivalent and substitute parts ensures design continuity and supply chain flexibility for applications requiring positive adjustable voltage regulation with 1.5A output capability.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Part Number	LM317T
Category	Power Management (PMIC)
Package / Case	TO-220-3
Output Configuration	Positive
Output Type	Adjustable
Current - Output	1.5A
Voltage - Input (Max)	37V
Voltage - Output (Min/Fixed)	1.25V
Voltage - Output (Max)	37V
Current - Quiescent (Iq)	10 mA
PSRR	64dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit
Operating Temperature	0°C ~ 125°C
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the LM317T is determined by the following critical parameters: output current rating (1.5A), package type (TO-220-3), output configuration (positive adjustable), voltage range (input max 37V or higher, output 1.25V to 37V), and protection features (over current, over temperature, short circuit). Parts are grouped into two categories:

Category 1: Direct Equivalents (1.5A Output) Parts with identical 1.5A output current rating, matching voltage specifications, and equivalent protection features. These provide pin-for-pin compatibility and identical electrical performance.

Category 2: Functional Alternatives (500mA Output) Parts with reduced output current (500mA) but identical package, voltage range, and adjustable output configuration. These are suitable for applications with lower current requirements but maintain the same form factor and basic functionality.

Parameter Comparison

Part Number	Manufacturer	Product Status	Current - Output	Voltage - Input (Max)	Voltage - Output (Min)	Operating Temperature	Protection Features	Package
LM317T	Texas Instruments	Last Time Buy	1.5A	37V	1.25V	0°C ~ 125°C	Over Current, Over Temperature, Short Circuit	TO-220-3
LM317T/NOPB	Texas Instruments	Active	1.5A	37V	1.25V	0°C ~ 125°C	Over Current, Over Temperature, Short Circuit	TO-220-3
LM217T	STMicroelectronics	Active	1.5A	40V	1.2V	-25°C ~ 150°C	Over Current, Over Temperature	TO-220-3
LM317BTG	onsemi	Active	1.5A	40V	1.2V	-40°C ~ 125°C	Over Current, Over Temperature, Short Circuit	TO-220-3
LM317TG	onsemi	Active	1.5A	40V	1.2V	0°C ~ 125°C	Over Current, Over Temperature, Short Circuit	TO-220-3
LM317T (NTE Electronics)	NTE Electronics, Inc	Active	1.5A	37V	1.25V	0°C ~ 125°C	Over Current, Over Temperature, Short Circuit	TO-220-3
LM317MABTG	onsemi	Active	500mA	40V	1.2V	-40°C ~ 125°C	Over Current, Over Temperature, Short Circuit	TO-220-3
LM317MBTG	onsemi	Active	500mA	40V	1.2V	-40°C ~ 125°C	Over Current, Over Temperature, Short Circuit	TO-220-3
LM317MTG	onsemi	Active	500mA	40V	1.2V	0°C ~ 125°C	Over Current, Over Temperature, Short Circuit	TO-220-3

Engineering Selection Recommendations

Primary Substitutes (1.5A Output - Direct Equivalents)

LM317T/NOPB from Texas Instruments is the recommended first choice. It maintains identical specifications to the original LM317T while offering Active product status and higher inventory availability (188,400 pcs). This part is functionally identical with no design modifications required.

LM317TG from onsemi provides an Active alternative with enhanced input voltage rating (40V vs 37V) and identical 1.5A output current. Operating temperature range matches the original (0°C ~ 125°C). This part is suitable for direct substitution in existing designs.

LM317BTG from onsemi offers the widest operating temperature range (-40°C ~ 125°C) among 1.5A alternatives, with input voltage rating of 40V. This part is appropriate for applications requiring extended temperature performance.

LM217T from STMicroelectronics provides 1.5A output with the broadest operating temperature range (-25°C ~ 150°C) and highest input voltage rating (40V). Note that short circuit protection is not listed; verify application requirements before selection.

LM317T from NTE Electronics, Inc maintains identical electrical specifications to the original Texas Instruments part with Active product status.

Secondary Substitutes (500mA Output - Reduced Current)

LM317MABTG, LM317MBTG, and LM317MTG from onsemi are suitable only for applications with maximum output current requirements of 500mA or less. These parts share the same TO-220-3 package and adjustable output configuration but deliver half the current capacity. Selection among these three depends on operating temperature requirements: LM317MABTG and LM317MBTG support -40°C ~ 125°C, while LM317MTG supports 0°C ~ 125°C.

Frequently Asked Questions (FAQ)

Q: Can I use LM317T/NOPB as a direct replacement for LM317T?

A: Yes. LM317T/NOPB is electrically and mechanically identical to LM317T. The "/NOPB" designation indicates lead-free solder coating. Both parts share the same TO-220-3 package, 1.5A output current, voltage specifications, and protection features. The primary difference is product status: LM317T/NOPB is Active with higher inventory availability.

Q: What is the difference between LM317T and LM217T?

A: Both parts deliver 1.5A output in TO-220-3 packages with adjustable positive output. Key differences: LM217T has higher input voltage rating (40V vs 37V), lower minimum output voltage (1.2V vs 1.25V), and extended operating temperature range (-25°C ~ 150°C vs 0°C ~ 125°C). LM217T does not list short circuit protection. Verify application requirements before substitution.

Q: Can I use 500mA parts (LM317MABTG, LM317MBTG, LM317MTG) in place of LM317T?

A: Only if your application requires maximum output current of 500mA or less. These parts are not suitable for applications requiring the full 1.5A output capacity of the original LM317T. All three maintain the same TO-220-3 package and adjustable output configuration.

Q: What does "Last Time Buy" status mean for LM317T?

A: Last Time Buy indicates the original Texas Instruments LM317T has limited remaining availability. Existing inventory will not be replenished. For new designs or long-term supply requirements, select from Active status alternatives such as LM317T/NOPB, LM317TG, or LM317BTG.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts carry RoHS3 compliance certification, matching the original LM317T specification.

Q: Which substitute offers the best temperature performance?

A: LM217T from STMicroelectronics provides the widest operating temperature range (-25°C ~ 150°C). For extended high-temperature operation, LM317BTG and LM317MABTG/MBTG from onsemi support -40°C minimum operating temperature.

Q: Do all 1.5A alternatives have identical pin configurations?

A: Yes. All 1.5A substitute parts (LM317T/NOPB, LM217T, LM317BTG, LM317TG, and NTE LM317T) use the TO-220-3 package with identical pin assignments, enabling direct PCB substitution without layout modifications.

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