LP5951MF-3.0 Linear Voltage Regulator — Equivalent & Substitute Parts

Part Overview

The LP5951MF-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 production continuity. 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
Manufacturer	Texas Instruments
Part Number	LP5951MF-3.0
Product Status	Obsolete
Output Voltage (Fixed)	3V
Output Current	150mA
Input Voltage (Max)	5.5V
Dropout Voltage (Max)	0.35V @ 150mA
Quiescent Current	55 µA
Package	SOT-23-5 (SC-74A)
Operating Temperature	-40°C ~ 125°C
Protection Features	Overcurrent, Over-Temperature, Short Circuit
RoHS Status	Non-compliant

Substitute Part Grouping Explanation

Substitution for the LP5951MF-3.0 is determined by the following critical parameters:

Output Voltage: Must be fixed at 3V
Output Current Capability: Minimum 150mA (higher ratings acceptable)
Package Type: SOT-23-5 or equivalent surface mount package
Input Voltage Range: Maximum input voltage of 5.5V or higher
Dropout Voltage: Lower or equal to 0.35V @ rated current
Operating Temperature Range: Must cover -40°C to 125°C or equivalent
Protection Features: Overcurrent and thermal shutdown required
Control Features: Enable pin functionality required

Substitutes are grouped into three categories:

Direct Manufacturer Equivalents (Texas Instruments LP5951 series variants)
Parametric Equivalents (Alternative manufacturers with matching electrical specifications)
Manufacturer-Recommended Alternatives (Higher performance or enhanced feature sets)

Parameter Comparison

Part Number	Manufacturer	Output Current	Dropout Voltage	Quiescent Current	Operating Temp	Package	Product Status	RoHS Status
LP5951MF-3.0	Texas Instruments	150mA	0.35V @ 150mA	55 µA	-40°C ~ 125°C	SOT-23-5	Obsolete	Non-compliant
LP5951MF-3.0/NOPB	Texas Instruments	150mA	0.35V @ 150mA	55 µA	-40°C ~ 125°C	SOT-23-5	Active	ROHS3 Compliant
LP5951MFX-3.0/NOPB	Texas Instruments	150mA	0.35V @ 150mA	55 µA	-40°C ~ 125°C	SOT-23-5	Active	ROHS3 Compliant
S-1312A30-M5T1U3	ABLIC Inc.	150mA	0.28V @ 100mA	30 µA	-40°C ~ 85°C	SOT-23-5	Active	ROHS3 Compliant
S-1312B30-M5T1U3	ABLIC Inc.	150mA	0.28V @ 100mA	30 µA	-40°C ~ 85°C	SOT-23-5	Active	ROHS3 Compliant
S-1312C30-M5T1U3	ABLIC Inc.	150mA	0.28V @ 100mA	30 µA	-40°C ~ 85°C	SOT-23-5	Active	ROHS3 Compliant
S-1312D30-M5T1U3	ABLIC Inc.	150mA	0.28V @ 100mA	30 µA	-40°C ~ 85°C	SOT-23-5	Active	ROHS3 Compliant
S-1313A30-M5T1U3	ABLIC Inc.	200mA	0.32V @ 100mA	1.35 µA	-40°C ~ 85°C	SOT-23-5	Active	ROHS3 Compliant
BU30SD2MG-MTR	Rohm Semiconductor	200mA	0.15V @ 100mA	80 µA	-40°C ~ 105°C	5-SSOP	Active	ROHS3 Compliant
MIC5307-3.0YD5-TR	Microchip Technology	300mA	0.25V @ 300mA	30 µA	-40°C ~ 125°C	TSOT-23-5	Active	ROHS3 Compliant
S-1135C30-M5T1U	ABLIC Inc.	300mA	Not specified	1 µA	-40°C ~ 85°C	SOT-23-5	Obsolete	ROHS3 Compliant

Engineering Selection Recommendations

Direct Replacement (Preferred for Pin-Compatible Designs)

LP5951MF-3.0/NOPB and LP5951MFX-3.0/NOPB are the primary alternatives. Both maintain identical electrical specifications to the original part while offering active product status and ROHS3 compliance. These variants are sourced from the same manufacturer and require no circuit redesign.

ABLIC S-1312 Series (150mA Output Current)

The S-1312A30-M5T1U3, S-1312B30-M5T1U3, S-1312C30-M5T1U3, and S-1312D30-M5T1U3 provide 150mA output current matching the original specification. These parts feature improved dropout voltage (0.28V vs. 0.35V) and lower quiescent current (30 µA vs. 55 µA). Operating temperature range is limited to -40°C ~ 85°C, which is acceptable for most applications not requiring the full 125°C upper limit. All variants are ROHS3 compliant and actively produced.

Higher Current Alternatives (200mA and 300mA)

For applications requiring additional current margin, the S-1313A30-M5T1U3 (200mA), BU30SD2MG-MTR (200mA), and MIC5307-3.0YD5-TR (300mA) provide enhanced output current capability. The MIC5307-3.0YD5-TR maintains the full -40°C ~ 125°C operating range and offers the highest current rating (300mA) with superior dropout voltage performance (0.25V @ 300mA). Package differences must be evaluated for PCB layout compatibility.

Compliance Considerations

The original LP5951MF-3.0 is RoHS non-compliant. All recommended substitutes are ROHS3 compliant, supporting modern manufacturing and environmental requirements. Product status transitions from obsolete to active for all primary recommendations, ensuring long-term availability and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can I use a higher current-rated regulator as a direct substitute?

A: Yes, provided the output voltage (3V fixed), package type (SOT-23-5 or compatible), and control features (Enable pin) remain unchanged. Higher current ratings provide design margin without affecting circuit operation. Verify PCB layout compatibility with the selected package.

Q: What is the difference between LP5951MF-3.0 and LP5951MF-3.0/NOPB?

A: The /NOPB suffix indicates "No Lead (Pb)" and represents the RoHS-compliant version. Electrical specifications are identical. The /NOPB variant is actively produced while the original is obsolete.

Q: Are ABLIC S-1312 variants interchangeable with each other?

A: Yes. The S-1312A30-M5T1U3, S-1312B30-M5T1U3, S-1312C30-M5T1U3, and S-1312D30-M5T1U3 share identical electrical specifications and SOT-23-5 packaging. Differences are internal process variations. All are suitable for direct substitution.

Q: Why does the MIC5307-3.0YD5-TR have a different package designation (TSOT-23-5)?

A: TSOT-23-5 is a thin variant of SOT-23-5 with identical pin configuration and spacing. It is mechanically compatible with standard SOT-23-5 footprints. Verify PCB assembly equipment compatibility with thin package profiles.

Q: What is the impact of operating temperature range differences?

A: The original LP5951MF-3.0 operates to 125°C. ABLIC S-1312 and S-1313 variants are rated to 85°C. If your application requires operation above 85°C, select MIC5307-3.0YD5-TR (125°C) or maintain the Texas Instruments LP5951MF-3.0/NOPB variant.

Q: Can I substitute the BU30SD2MG-MTR (5-SSOP package) directly?

A: No. The 5-SSOP package has different pin spacing and layout compared to SOT-23-5. PCB redesign is required. This option is suitable only when layout modifications are acceptable and the automotive-grade qualification (AEC-Q100) is beneficial.

Q: What does ROHS3 compliance mean?

A: ROHS3 compliance indicates the part meets the Restriction of Hazardous Substances Directive, restricting lead, cadmium, mercury, and other hazardous materials. This is required for most modern electronics manufacturing and distribution.

Q: Is the lower quiescent current of ABLIC parts significant?

A: Yes. ABLIC S-1312 series (30 µA) and S-1313 series (1.35 µA) consume less standby power than the original LP5951MF-3.0 (55 µA). This is beneficial for battery-powered or low-power applications where quiescent current contributes to overall power consumption.

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