LP3984IMF-3.1/NOPB Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LP3984IMF-3.1/NOPB is a linear voltage regulator IC from Texas Instruments designed for positive fixed 3.1V 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 3.1V output with integrated enable control and protection features including over-temperature and short-circuit protection, suitable for low-power applications requiring stable voltage regulation in compact form factors.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Part Number	LP3984IMF-3.1/NOPB
Output Voltage	3.1V Fixed
Output Current	150mA
Input Voltage (Max)	6V
Dropout Voltage	0.12V @ 150mA
Quiescent Current	125 µA
Package	SOT-23-5 (SC-74A)
Operating Temperature	-40°C to 125°C
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the LP3984IMF-3.1/NOPB is determined by the following critical parameters:

Primary Substitution Criteria:

Output voltage: 3.1V fixed (exact match required)
Output current capability: minimum 150mA
Package type: SOT-23-5 compatible
Input voltage rating: minimum 5.5V to 6V
Operating temperature range: -40°C to 125°C minimum
Surface mount technology
Enable control feature
Protection features: Over-temperature and short-circuit minimum

Substitution Categories:

Direct Equivalents (150mA output, 3.1V): Parts with identical output current and voltage specifications, suitable for direct replacement in existing designs.

Enhanced Substitutes (higher output current, 3.1V): Parts with 200mA to 300mA output capability at 3.1V, providing improved current headroom while maintaining voltage compatibility.

Alternative Voltage Substitutes (3.3V output): Parts with 3.3V fixed output instead of 3.1V, usable only in applications tolerant of the 0.2V voltage difference.

Lower Current Substitutes (100mA output, 3.1V): Parts with reduced output current capability, suitable only for applications with current requirements below 100mA.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage	Quiescent Current	Package	Operating Temp	Product Status
LP3984IMF-3.1/NOPB	Texas Instruments	3.1V	150mA	6V	0.12V @ 150mA	125 µA	SOT-23-5	-40°C to 125°C	Obsolete
LP5907MFX-3.1/NOPB	Texas Instruments	3.1V	250mA	5.5V	0.25V @ 250mA	25 µA	SOT-23-5	-40°C to 125°C	Active
ADP162AUJZ-3.1-R7	Analog Devices Inc.	3.1V	150mA	5.5V	Not specified	1.25 µA	TSOT-23-5	-40°C to 125°C	Active
BU31TD3WG-TR	Rohm Semiconductor	3.1V	200mA	6V	0.46V @ 200mA	60 µA	5-SSOP	-40°C to 85°C	Active
MIC5255-3.1YM5-TR	Microchip Technology	3.1V	150mA	6V	0.25V @ 150mA	150 µA	SOT-23-5	-40°C to 125°C	Active
MIC5365-3.3YD5-T5	Microchip Technology	3.3V	150mA	5.5V	0.31V @ 150mA	39 µA	TSOT-23-5	-40°C to 125°C	Active
MIC5365-3.3YD5-TR	Microchip Technology	3.3V	150mA	5.5V	0.31V @ 150mA	39 µA	TSOT-23-5	-40°C to 125°C	Active
RT9169H-31GB	Richtek USA Inc.	3.1V	100mA	6V	0.6V @ 100mA	7 µA	SOT-23-5	-40°C to 85°C	Active
RT9169H-33GB	Richtek USA Inc.	3.3V	100mA	6V	0.6V @ 100mA	7 µA	SOT-23-5	-40°C to 85°C	Active
S-1132B31-M5T1U	ABLIC Inc.	3.1V	300mA	6.5V	0.19V @ 100mA	1 µA	SOT-23-5	-40°C to 85°C	Active
S-1167B31-M5T1U	ABLIC Inc.	3.1V	150mA	6.5V	0.23V @ 100mA	900 nA	SOT-23-5	-40°C to 85°C	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications):

MIC5255-3.1YM5-TR and S-1167B31-M5T1U provide the closest functional equivalence to LP3984IMF-3.1/NOPB with 3.1V output and 150mA current rating. Both are active products with ROHS3 compliance and SOT-23-5 packaging. MIC5255-3.1YM5-TR maintains the full -40°C to 125°C operating range matching the original part. S-1167B31-M5T1U operates to 85°C maximum but offers superior quiescent current performance at 900 nA.

For Enhanced Current Capability:

LP5907MFX-3.1/NOPB from Texas Instruments offers 250mA output at 3.1V in active production status with SOT-23-5 packaging and full temperature range. S-1132B31-M5T1U from ABLIC provides 300mA output at 3.1V with exceptionally low quiescent current of 1 µA, though operating temperature is limited to 85°C.

For Voltage-Tolerant Applications:

MIC5365-3.3YD5-TR and MIC5365-3.3YD5-T5 deliver 3.3V output at 150mA in active status with ROHS3 compliance. These are suitable only for designs tolerating 0.2V higher output voltage.

For Current-Limited Applications:

RT9169H-31GB provides 3.1V at 100mA output in active status with SOT-23-5 packaging, suitable for applications requiring less than 100mA.

All recommended substitutes maintain ROHS3 compliance, REACH unaffected status, and EAR99 ECCN classification consistent with the original part.

Frequently Asked Questions (FAQ)

Q: Can LP5907MFX-3.1/NOPB directly replace LP3984IMF-3.1/NOPB?

A: Yes, LP5907MFX-3.1/NOPB is a direct functional replacement with identical 3.1V output voltage and SOT-23-5 packaging. The higher 250mA output current provides additional headroom for applications originally designed for 150mA. Both parts maintain -40°C to 125°C operating range and ROHS3 compliance.

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 and electrically compatible for PCB mounting. Verify PCB footprint clearance requirements before substituting TSOT-23-5 parts in designs originally specified for standard SOT-23-5.

Q: Can I use MIC5365-3.3YD5-TR instead of LP3984IMF-3.1/NOPB?

A: MIC5365-3.3YD5-TR outputs 3.3V instead of 3.1V, a 0.2V difference. Substitution is only valid for applications with voltage tolerance specifications that accept 3.3V output. Verify circuit design requirements before implementation.

Q: Why does S-1132B31-M5T1U have lower operating temperature maximum than LP3984IMF-3.1/NOPB?

A: S-1132B31-M5T1U operates to 85°C maximum versus 125°C for LP3984IMF-3.1/NOPB. This limits use to applications with ambient temperature requirements not exceeding 85°C. Verify thermal environment specifications before selection.

Q: What is the significance of quiescent current differences between substitute parts?

A: Quiescent current ranges from 900 nA (S-1167B31-M5T1U) to 150 µA (MIC5255-3.1YM5-TR). Lower quiescent current reduces standby power consumption. Select based on application power budget requirements and duty cycle characteristics.

Q: Are all substitute parts ROHS3 compliant?

A: Yes, all listed substitute parts maintain ROHS3 compliance and REACH unaffected status consistent with LP3984IMF-3.1/NOPB, ensuring regulatory compliance for new designs.

Q: What does "Active" product status mean versus "Obsolete"?

A: Active status indicates the part is in current production with ongoing manufacturer support and availability. Obsolete status indicates the part is no longer manufactured. Substituting with active parts ensures long-term supply chain continuity.

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