LM317MABT Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LM317MABT is a linear voltage regulator IC from onsemi, configured for positive adjustable output at 500mA in a TO-220-3 package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The LM317MABT provides adjustable output voltage regulation from 1.2V to 37V with integrated protection features including over-current, over-temperature, and short-circuit protection.

Key Parameters

Parameter	Value
Manufacturer	onsemi
Part Number	LM317MABT
Category	Power Management (PMIC)
Package / Case	TO-220-3
Output Configuration	Positive
Output Type	Adjustable
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	1.2V
Voltage - Output (Max)	37V
Current - Output	500mA
Current - Quiescent (Iq)	10 mA
PSRR	80dB ~ 65dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit
Operating Temperature	-40°C ~ 125°C (TJ)
Mounting Type	Through Hole
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution for the LM317MABT is determined by the following critical parameters: output configuration (positive), output type (adjustable), package type (TO-220-3), mounting method (through-hole), and protection features (over-current, over-temperature, short-circuit). The substitute parts are grouped into two categories:

Direct Manufacturer Equivalents maintain identical electrical specifications and are sourced from the same manufacturer (onsemi). These parts differ only in product status and packaging format.

Parametric Equivalents and Similar Parts share the same base product number (LM317) and core functional characteristics but may have variations in output current rating, minimum output voltage, operating temperature range, or manufacturer. These parts are functionally compatible for most applications but require verification of specific current and voltage requirements.

Parameter Comparison

Parameter	LM317MABT	LM317MABTG	LM317MBTG	LM317AT/NOPB	LM317KCS	LM317KCSE3	LM317T	LM317T/NOPB
Manufacturer	onsemi	onsemi	onsemi	Texas Instruments	Texas Instruments	Texas Instruments	NTE Electronics, Inc	Texas Instruments
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Output Configuration	Positive	Positive	Positive	Positive	Positive	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable
Voltage - Input (Max)	40V	40V	40V	40V	40V	40V	37V	37V
Voltage - Output (Min/Fixed)	1.2V	1.2V	1.2V	1.25V	1.25V	1.25V	1.25V	1.25V
Voltage - Output (Max)	37V	37V	37V	37V	37V	37V	37V	37V
Current - Output	500mA	500mA	500mA	1.5A	1.5A	1.5A	1.5A	1.5A
Current - Quiescent (Iq)	10 mA	10 mA	10 mA	10 mA	10 mA	10 mA	Not specified	10 mA
PSRR	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	64dB (120Hz)	64dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit
Operating Temperature	-40°C ~ 125°C (TJ)	-40°C ~ 125°C (TJ)	-40°C ~ 125°C (TJ)	-40°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Product Status	Obsolete	Active	Active	Active	Active	Last Time Buy	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Replacement (onsemi sourced): LM317MABTG and LM317MBTG are the preferred direct replacements for the obsolete LM317MABT. Both parts maintain identical electrical specifications and TO-220-3 packaging. LM317MABTG is available in tube packaging and carries Active product status with ROHS3 compliance. LM317MBTG is also Active with ROHS3 compliance and offers the highest inventory availability (6375 units).

Higher Current Alternatives: LM317AT/NOPB, LM317KCS, LM317KCSE3, LM317T, and LM317T/NOPB provide 1.5A output current compared to the 500mA rating of the LM317MABT. These parts are suitable for applications requiring higher current delivery while maintaining the same adjustable voltage regulation topology. All are ROHS3 compliant and available from active product lines. LM317T/NOPB from Texas Instruments offers the highest inventory (188400 units) and Active status.

Temperature Range Consideration: The LM317MABT operates from -40°C to 125°C. Substitute parts from Texas Instruments (LM317KCS, LM317KCSE3, LM317T, LM317T/NOPB) operate from 0°C to 125°C, reducing the lower temperature limit by 40°C. Applications requiring operation below 0°C must use onsemi-sourced alternatives (LM317MABTG or LM317MBTG).

Input Voltage Specification: LM317MABT, LM317MABTG, LM317MBTG, and LM317AT/NOPB support 40V maximum input. LM317T and LM317T/NOPB are rated for 37V maximum input, reducing headroom by 3V. Circuit designs operating near 40V input must use onsemi parts or LM317AT/NOPB.

Compliance Status: All substitute parts except the original LM317MABT are ROHS3 compliant. For applications requiring RoHS compliance, any substitute part listed is acceptable. The original part is RoHS non-compliant.

Frequently Asked Questions (FAQ)

Q: Can I use LM317MABTG as a direct replacement for LM317MABT?

A: Yes. LM317MABTG is a direct equivalent with identical electrical specifications, output current (500mA), voltage ratings, and operating temperature range (-40°C to 125°C). The primary difference is product status (Active vs. Obsolete) and packaging format (Tube vs. unspecified). Both are onsemi manufactured parts in TO-220-3 packages.

Q: What is the difference between the 500mA and 1.5A versions?

A: The LM317MABT is rated for 500mA maximum output current. Substitute parts LM317AT/NOPB, LM317KCS, LM317KCSE3, LM317T, and LM317T/NOPB are rated for 1.5A. The higher current rating allows these parts to deliver greater load current while maintaining the same adjustable voltage regulation. All other electrical characteristics remain equivalent. Selection depends on application current requirements.

Q: Are there temperature range differences I should know about?

A: Yes. The LM317MABT and onsemi equivalents (LM317MABTG, LM317MBTG) operate from -40°C to 125°C. Texas Instruments parts (LM317KCS, LM317KCSE3, LM317T, LM317T/NOPB) operate from 0°C to 125°C. If your application requires operation below 0°C, use onsemi-sourced parts. For standard industrial temperature ranges (0°C to 125°C), all parts are suitable.

Q: What is the maximum input voltage for each substitute?

A: LM317MABT, LM317MABTG, LM317MBTG, and LM317AT/NOPB support 40V maximum input voltage. LM317T and LM317T/NOPB are rated for 37V maximum input. If your circuit operates at or near 40V input, use parts rated for 40V input. For applications below 37V, all parts are suitable.

Q: Are all substitute parts RoHS compliant?

A: All substitute parts listed are ROHS3 compliant. The original LM317MABT is RoHS non-compliant. If your application or supply chain requires RoHS compliance, any substitute part is acceptable.

Q: Which substitute has the best availability?

A: LM317T/NOPB from Texas Instruments has the highest inventory availability at 188,400 units. LM317MBTG from onsemi has 6,375 units available. Both are Active products suitable for new designs.

Q: Can I use NTE Electronics LM317T as a substitute?

A: Yes. NTE Electronics LM317T is functionally equivalent with identical voltage ratings and protection features. It is rated for 1.5A output current and operates from 0°C to 125°C. The maximum input voltage is 37V. This part is suitable for applications not requiring -40°C operation or 40V input capability.

Q: What is the minimum output voltage for each part?

A: LM317MABT, LM317MABTG, and LM317MBTG have a minimum output voltage of 1.2V. All other substitute parts (LM317AT/NOPB, LM317KCS, LM317KCSE3, LM317T, LM317T/NOPB) have a minimum output voltage of 1.25V. This 0.05V difference is negligible for most applications.

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