LM317EMP Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LM317EMP is a positive adjustable linear voltage regulator IC manufactured by Texas Instruments, rated for 1.5A output current in SOT-223-4 surface mount packaging. This device is classified as Last Time Buy, indicating discontinued production status. The LM317EMP provides adjustable output voltage regulation from 1.25V to 37V with integrated protection features including over-current, over-temperature, and short-circuit protection.

Finding equivalent and substitute parts is necessary due to the Last Time Buy status of the LM317EMP. Alternative parts with matching or compatible electrical and mechanical specifications ensure design continuity and supply chain reliability.

Key Parameters

Parameter	LM317EMP Value
Manufacturer	Texas Instruments
Output Configuration	Positive
Output Type	Adjustable
Number of Regulators	1
Voltage - Input (Max)	37V
Voltage - Output (Min/Fixed)	1.25V
Voltage - Output (Max)	37V
Current - Output	1.5A
Current - Quiescent (Iq)	10 mA
PSRR	80dB ~ 65dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit
Operating Temperature	0°C ~ 125°C
Mounting Type	Surface Mount
Package / Case	TO-261-4, TO-261AA
Supplier Device Package	SOT-223-4
Base Product Number	LM317

Substitute Part Grouping Explanation

Substitute parts for the LM317EMP are classified into two categories based on electrical and mechanical compatibility:

Parametric Equivalents (Direct Replacements): Parts that match all critical electrical parameters and package specifications of the LM317EMP. These parts maintain identical voltage ratings (37V input max, 1.25V to 37V output), current output (1.5A), quiescent current (10 mA), PSRR characteristics, protection features, and SOT-223-4 packaging. The primary distinction is product status and compliance certification.

Manufacturer Recommended Alternatives: Parts that share the same base product number (LM317) and functional architecture but differ in output current rating (500mA vs. 1.5A) and operating temperature range. These parts are suitable for applications where the lower current rating is acceptable and provide extended temperature range or automotive-grade qualification options.

Key parameters determining substitution eligibility:

Output Configuration: Positive
Output Type: Adjustable
Voltage ratings: Input max 37V–40V, Output 1.25V–1.2V minimum to 37V maximum
Package: SOT-223 (TO-261) form factor
Protection Features: Over Current, Over Temperature, Short Circuit
Mounting Type: Surface Mount

Parameter Comparison

Parameter	LM317EMP	LM317EMP/NOPB	LM317EMPX/NOPB	LM317MBSTT3G	LM317MSTT3G	NCV317MBSTT3G
Manufacturer	Texas Instruments	Texas Instruments	Texas Instruments	onsemi	onsemi	onsemi
Output Configuration	Positive	Positive	Positive	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable
Number of Regulators	1	1	1	1	1	1
Voltage - Input (Max)	37V	37V	37V	40V	40V	40V
Voltage - Output (Min/Fixed)	1.25V	1.25V	1.25V	1.2V	1.2V	1.2V
Voltage - Output (Max)	37V	37V	37V	37V	37V	37V
Current - Output	1.5A	1.5A	1.5A	500mA	500mA	500mA
Current - Quiescent (Iq)	10 mA	10 mA	10 mA	10 mA	10 mA	10 mA
PSRR	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (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
Operating Temperature	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA
Supplier Device Package	SOT-223-4	SOT-223-4	SOT-223-4	SOT-223 (TO-261)	SOT-223 (TO-261)	SOT-223 (TO-261)
Product Status	Last Time Buy	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Affected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

For Direct Replacement (1.5A Output Current):

LM317EMP/NOPB and LM317EMPX/NOPB are parametric equivalents manufactured by Texas Instruments with identical electrical specifications and current ratings. Both parts are in Active product status, ROHS3 compliant, and REACH unaffected. These parts are suitable for applications requiring the full 1.5A output current specification and maintain compatibility with existing designs using the LM317EMP.

For Alternative Designs (500mA Output Current):

LM317MBSTT3G and LM317MSTT3G are onsemi-manufactured alternatives with reduced output current (500mA) and extended input voltage rating (40V max). LM317MSTT3G maintains the 0°C to 125°C operating temperature range matching the LM317EMP. LM317MBSTT3G extends the operating temperature to -40°C to 125°C, suitable for industrial applications.

For Automotive Applications:

NCV317MBSTT3G is an automotive-grade alternative qualified to AEC-Q100 with -40°C to 125°C operating temperature range. This part is suitable for automotive and harsh environment applications where extended temperature performance and automotive qualification are required.

All substitute parts maintain SOT-223 (TO-261) packaging compatibility, identical protection features, and equivalent PSRR characteristics. Selection between alternatives depends on output current requirements, operating temperature range, and compliance certifications needed for the target application.

Frequently Asked Questions (FAQ)

Q: Can LM317MBSTT3G or LM317MSTT3G replace LM317EMP in applications requiring 1.5A output?

A: No. LM317MBSTT3G and LM317MSTT3G are rated for 500mA maximum output current, compared to 1.5A for the LM317EMP. These parts are suitable only for applications where the load current does not exceed 500mA. For applications requiring 1.5A output, use LM317EMP/NOPB or LM317EMPX/NOPB.

Q: Are LM317EMP/NOPB and LM317EMPX/NOPB interchangeable?

A: Yes. Both parts are Texas Instruments-manufactured parametric equivalents with identical electrical specifications, current ratings, voltage ranges, and SOT-223-4 packaging. The primary difference is product status (both Active) and inventory availability.

Q: What is the difference between LM317MSTT3G and LM317MBSTT3G?

A: Both parts are onsemi-manufactured with 500mA output current and 40V maximum input voltage. The primary difference is operating temperature range: LM317MSTT3G operates from 0°C to 125°C, while LM317MBSTT3G operates from -40°C to 125°C. Select LM317MBSTT3G for applications requiring extended low-temperature performance.

Q: Is NCV317MBSTT3G suitable for non-automotive applications?

A: Yes. NCV317MBSTT3G is automotive-qualified but functionally compatible with non-automotive designs. The automotive qualification (AEC-Q100) and extended temperature range (-40°C to 125°C) provide additional reliability margins suitable for industrial and harsh environment applications.

Q: What is the impact of the LM317EMP Last Time Buy status?

A: Last Time Buy status indicates discontinued production. Existing inventory is limited. For new designs or long-term supply requirements, transition to LM317EMP/NOPB, LM317EMPX/NOPB (for 1.5A applications), or alternative onsemi parts (for 500mA applications or extended temperature range).

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts (LM317EMP/NOPB, LM317EMPX/NOPB, LM317MBSTT3G, LM317MSTT3G, NCV317MBSTT3G) are ROHS3 compliant. The original LM317EMP is RoHS non-compliant.

Q: Do all parts use the same SOT-223 package?

A: Yes. All parts use SOT-223 (TO-261) surface mount packaging with TO-261-4 and TO-261AA case designations, ensuring mechanical and thermal compatibility in existing PCB layouts.

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