LP5951MFX-3.0 Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LP5951MFX-3.0 is a linear voltage regulator IC from Texas Instruments designed for positive fixed 3V output at 150mA in SOT-23-5 surface mount packaging. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The device provides regulated 3V output with integrated protection features including overcurrent, over-temperature, and short-circuit protection, suitable for low-power applications requiring stable voltage regulation.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3V
Output Current	150mA
Input Voltage (Max)	5.5V
Dropout Voltage (Max)	0.35V @ 150mA
Quiescent Current	55 µA
Package Type	SOT-23-5 (SC-74A)
Operating Temperature Range	-40°C to 125°C
Protection Features	Overcurrent, Over-Temperature, Short-Circuit

Substitute Part Grouping Explanation

Substitute parts for the LP5951MFX-3.0 are categorized based on the following critical parameters that determine functional equivalence:

Primary Substitution Criteria:

Fixed output voltage of 3V
Output current capability (150mA minimum for direct equivalence; higher ratings acceptable)
SOT-23-5 package compatibility
Input voltage rating of 5.5V or higher
Operating temperature range of -40°C to 125°C or compatible subset
Enable control feature
Surface mount technology

Substitution Categories:

Direct Equivalents (Same Output Current - 150mA): Parts with identical 150mA output current rating in SOT-23-5 packaging maintain pin-for-pin compatibility and identical electrical performance.

Higher Current Capacity Substitutes (200mA-300mA): Parts with increased output current ratings provide enhanced capability while maintaining voltage regulation and package compatibility. These are suitable for applications where additional current headroom is beneficial.

Parametric Equivalents (Different Packaging or Specifications): Parts with equivalent electrical performance but different package types or slightly modified specifications require board-level design verification.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage	Package	Operating Temp	Product Status	RoHS Status
LP5951MFX-3.0	Texas Instruments	3V	150mA	5.5V	0.35V @ 150mA	SOT-23-5	-40°C to 125°C	Obsolete	Non-compliant
LP5951MFX-3.0/NOPB	Texas Instruments	3V	150mA	5.5V	0.35V @ 150mA	SOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
LP5951MF-3.0/NOPB	Texas Instruments	3V	150mA	5.5V	0.35V @ 150mA	SOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
S-1312A30-M5T1U3	ABLIC Inc.	3V	150mA	5.5V	0.28V @ 100mA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
S-1312B30-M5T1U3	ABLIC Inc.	3V	150mA	5.5V	0.28V @ 100mA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
S-1312C30-M5T1U3	ABLIC Inc.	3V	150mA	5.5V	0.28V @ 100mA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
S-1312D30-M5T1U3	ABLIC Inc.	3V	150mA	5.5V	0.28V @ 100mA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
S-1313A30-M5T1U3	ABLIC Inc.	3V	200mA	5.5V	0.32V @ 100mA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
BU30SD2MG-MTR	Rohm Semiconductor	3V	200mA	6V	0.15V @ 100mA	5-SSOP	-40°C to 105°C	Active	ROHS3 Compliant
MIC5307-3.0YD5-TR	Microchip Technology	3V	300mA	5.5V	0.25V @ 300mA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
S-1135C30-M5T1U	ABLIC Inc.	3V	300mA	5.5V	Not specified	SOT-23-5	-40°C to 85°C	Obsolete	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Pin-Compatible, Same Performance):

The LP5951MFX-3.0/NOPB and LP5951MF-3.0/NOPB are direct equivalents from Texas Instruments with active product status and ROHS3 compliance. These parts maintain identical electrical specifications and packaging, making them suitable for direct substitution in existing designs. The /NOPB designation indicates lead-free, RoHS-compliant versions.

For Active Product Status with Extended Temperature Range:

The MIC5307-3.0YD5-TR from Microchip Technology provides 300mA output current in TSOT-23-5 packaging with the full -40°C to 125°C operating range matching the original part. This option offers increased current capacity and active product status. Board layout verification is required due to TSOT-23-5 package differences from SOT-23-5.

For 150mA Output Current Requirement:

The ABLIC S-1312 series (S-1312A30-M5T1U3, S-1312B30-M5T1U3, S-1312C30-M5T1U3, S-1312D30-M5T1U3) provides exact 150mA output current matching with improved dropout voltage performance (0.28V @ 100mA versus 0.35V @ 150mA). All variants are active products with ROHS3 compliance. Operating temperature range is -40°C to 85°C, which is acceptable for most applications but does not extend to 125°C.

For Higher Current Applications:

The S-1313A30-M5T1U3 from ABLIC and BU30SD2MG-MTR from Rohm Semiconductor provide 200mA output current. The BU30SD2MG-MTR offers superior dropout voltage (0.15V @ 100mA) and extended input voltage rating (6V), with automotive AEC-Q100 qualification. Package differences require design verification.

Compliance Considerations:

All recommended active substitutes carry ROHS3 compliance certification. The original LP5951MFX-3.0 is RoHS non-compliant; migration to compliant alternatives is necessary for new designs and regulatory adherence.

Frequently Asked Questions (FAQ)

Q: Can I use the S-1312 series parts as direct replacements for the LP5951MFX-3.0?

A: Yes. The S-1312A30-M5T1U3, S-1312B30-M5T1U3, S-1312C30-M5T1U3, and S-1312D30-M5T1U3 are pin-compatible SOT-23-5 packages with identical 3V output and 150mA current rating. The improved dropout voltage (0.28V @ 100mA) provides better performance. Operating temperature range is -40°C to 85°C instead of 125°C maximum; verify this meets application requirements.

Q: What is the difference between SOT-23-5 and TSOT-23-5 packaging?

A: TSOT-23-5 is a thin variant of SOT-23-5 with reduced height. Both are mechanically compatible in most applications, but PCB footprint and thermal characteristics may differ slightly. Consult device datasheets for specific dimensional requirements.

Q: Can I use the MIC5307-3.0YD5-TR with 300mA output instead of the 150mA LP5951MFX-3.0?

A: Yes. The MIC5307-3.0YD5-TR provides the same 3V output with higher current capacity in TSOT-23-5 packaging. This is suitable for applications where additional current headroom is beneficial or required. Verify PCB layout compatibility with the TSOT-23-5 package.

Q: Why is the BU30SD2MG-MTR recommended despite using 5-SSOP packaging instead of SOT-23-5?

A: The BU30SD2MG-MTR offers superior electrical performance with 0.15V dropout voltage, extended input voltage rating (6V), and automotive AEC-Q100 qualification. The 5-SSOP package requires PCB redesign but provides enhanced reliability for demanding applications. This is a parametric equivalent, not a pin-compatible replacement.

Q: Are all recommended substitutes RoHS compliant?

A: All active product substitutes listed carry ROHS3 compliance certification. The original LP5951MFX-3.0 is RoHS non-compliant. The S-1135C30-M5T1U is obsolete but ROHS3 compliant.

Q: What is the significance of the /NOPB designation on Texas Instruments parts?

A: The /NOPB suffix indicates a lead-free, RoHS-compliant version without plumbum (lead). This designation ensures compliance with environmental regulations and is standard for active product offerings.

Q: Can I substitute a 200mA or 300mA regulator in a circuit designed for 150mA?

A: Yes. Higher current-rated regulators are suitable for circuits designed for lower current. The regulator will supply only the current demanded by the load. Verify that input voltage, output voltage, package compatibility, and operating temperature range meet application requirements.

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