LM317MBT Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LM317MBT is a positive adjustable linear voltage regulator IC manufactured by onsemi, rated for 500mA output current in a TO-220-3 package. This part is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and production continuity. The LM317 series represents a foundational adjustable regulator topology with multiple manufacturer implementations and output current variants available in the active product market.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM317MBT
Manufacturer	onsemi
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 of the LM317MBT is determined by the following critical parameters: output voltage range (1.2V to 37V adjustable), positive output configuration, adjustable output type, TO-220-3 package compatibility, through-hole mounting, and protection features (over current, over temperature, short circuit).

Substitute parts are grouped into two categories:

Direct Equivalents (Parametric Match): Parts that maintain identical electrical specifications and package form factor. These include the LM317MBTG and LM317MABTG from onsemi, both rated for 500mA output current with matching voltage ranges and operating temperature specifications.

Similar Substitutes (Higher Current Rating): Parts that exceed the 500mA output specification while maintaining the same voltage range, package type, and protection features. These include the LM317AT/NOPB, LM317KCS, LM317KCSE3, LM317T, and LM317T/NOPB, all rated for 1.5A output current. These parts are electrically compatible for applications requiring the LM317MBT's voltage regulation characteristics and can deliver higher load current.

Parameter Comparison

Parameter	LM317MBT	LM317MBTG	LM317MABTG	LM317AT/NOPB	LM317KCS	LM317KCSE3	LM317T	LM317T/NOPB
Manufacturer	onsemi	onsemi	onsemi	Texas Instruments	Texas Instruments	Texas Instruments	NTE Electronics, Inc	Texas Instruments
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
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
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

For direct replacement of the LM317MBT, the LM317MBTG and LM317MABTG from onsemi are the primary equivalents, maintaining identical 500mA output current specifications and electrical characteristics. Both parts are in active product status with ROHS3 compliance, addressing the obsolescence of the original part while preserving exact electrical performance.

For applications where higher output current capacity is acceptable, the LM317AT/NOPB from Texas Instruments provides 1.5A output capability with active product status and ROHS3 compliance. This part maintains the 40V maximum input voltage specification and -40°C to 125°C operating temperature range of the original LM317MBT.

The LM317T/NOPB from Texas Instruments offers 1.5A output current with active product status and ROHS3 compliance. This part operates within a 0°C to 125°C temperature range, which represents a narrower operating window than the LM317MBT's -40°C specification.

The LM317KCS and LM317KCSE3 from Texas Instruments provide 1.5A output current with ROHS3 compliance. The LM317KCSE3 is designated as Last Time Buy, indicating limited future availability.

All substitute parts maintain the same TO-220-3 package form factor, positive adjustable output configuration, and comprehensive protection features (over current, over temperature, short circuit) as the original LM317MBT.

Frequently Asked Questions (FAQ)

Q: Can the LM317MBTG be used as a direct replacement for the LM317MBT?

A: Yes. The LM317MBTG maintains identical electrical specifications including 500mA output current, 1.2V to 37V adjustable output range, 40V maximum input voltage, and -40°C to 125°C operating temperature. Both parts use the TO-220-3 package. The primary difference is product status: LM317MBTG is active while LM317MBT is obsolete.

Q: What is the difference between the 500mA and 1.5A output current variants?

A: The LM317MBT, LM317MBTG, and LM317MABTG are rated for 500mA maximum output current. The LM317AT/NOPB, LM317KCS, LM317KCSE3, LM317T, and LM317T/NOPB are rated for 1.5A maximum output current. All parts share identical voltage regulation characteristics and protection features. The higher current variants can supply greater load current while maintaining the same output voltage adjustment range.

Q: Are all substitute parts RoHS compliant?

A: The LM317MBT is RoHS non-compliant. All listed substitute parts (LM317MBTG, LM317MABTG, LM317AT/NOPB, LM317KCS, LM317KCSE3, LM317T, and LM317T/NOPB) are ROHS3 compliant.

Q: What is the operating temperature difference between substitute parts?

A: The LM317MBT and LM317MBTG operate from -40°C to 125°C. The LM317AT/NOPB operates from -40°C to 125°C. The LM317KCS, LM317KCSE3, LM317T, and LM317T/NOPB operate from 0°C to 125°C. Applications requiring operation below 0°C must use parts with -40°C minimum temperature specification.

Q: Can I use a 1.5A rated part in place of a 500mA part?

A: Yes. The 1.5A rated variants (LM317AT/NOPB, LM317KCS, LM317KCSE3, LM317T, LM317T/NOPB) are electrically compatible with applications designed for the 500mA LM317MBT. The higher current rating provides additional design margin and does not affect voltage regulation performance. Thermal management and PCB layout must accommodate the specific part's power dissipation characteristics.

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

A: The LM317MBT, LM317MBTG, LM317MABTG, and LM317AT/NOPB are rated for 40V maximum input voltage. The LM317KCS and LM317KCSE3 are rated for 40V maximum input voltage. The LM317T and LM317T/NOPB are rated for 37V maximum input voltage. Applications with input voltages above 37V must use parts rated for 40V.

Q: Are there packaging differences between substitute parts?

A: All listed parts use the TO-220-3 through-hole package. Packaging format differs: LM317MBT uses standard packaging, LM317MBTG and LM317MABTG use tube packaging, LM317AT/NOPB, LM317KCS, LM317KCSE3, and LM317T/NOPB use tube packaging, and LM317T uses bag packaging. These differences affect supply chain handling but do not impact electrical performance or PCB mounting.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message