LP3984IMF-1.5 Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LP3984IMF-1.5 is a linear voltage regulator IC from Texas Instruments designed to deliver a fixed 1.5V output at 150mA in a compact SOT-23-5 surface mount package. This device features enable control, over-temperature protection, and short-circuit protection, operating across the industrial temperature range of -40°C to 125°C.

The LP3984IMF-1.5 is classified as obsolete. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support long-term product availability for applications currently using this regulator.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	1.5V
Output Current	150mA
Input Voltage (Max)	6V
Dropout Voltage (Max)	0.12V @ 150mA
Quiescent Current (Iq)	125 µA
Package Type	SOT-23-5 (SC-74A)
Operating Temperature	-40°C to 125°C
Control Features	Enable
Protection Features	Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitution eligibility for the LP3984IMF-1.5 is determined by the following critical parameters:

Output Voltage: Must be fixed at 1.5V
Output Current Capability: Minimum 150mA (equal or greater)
Input Voltage Range: Maximum input voltage of 5.5V to 6.5V
Package Type: SOT-23-5 or TSOT-23-5 (pin-compatible surface mount packages)
Operating Temperature Range: Must support -40°C to 125°C or equivalent industrial range
Control Features: Enable function required
Protection: Over-temperature and short-circuit protection required

Substitute parts are grouped into two categories:

Category A - Direct Replacements (150mA Output Current) Parts with 150mA output current matching the original specification exactly.

Category B - Enhanced Replacements (200mA+ Output Current) Parts with higher output current capability (200mA to 300mA) that maintain all other critical parameters, providing improved headroom for current-limited applications.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage (Max)	Quiescent Current (Iq)	Package	Operating Temp	Product Status	RoHS Status
LP3984IMF-1.5	Texas Instruments	1.5V	150mA	6V	0.12V @ 150mA	125 µA	SOT-23-5	-40°C to 125°C	Obsolete	Non-compliant
LP5907MFX-1.5/NOPB	Texas Instruments	1.5V	250mA	5.5V	0.25V @ 250mA	25 µA	SOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
ADP121-AUJZ15R7	Analog Devices Inc.	1.5V	150mA	5.5V	—	21 µA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
AP2122AK-1.5TRE1	Diodes Incorporated	1.5V	150mA	6V	0.6V @ 150mA	50 µA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
BU15TD3WG-TR	Rohm Semiconductor	1.5V	200mA	6V	0.7V @ 200mA	60 µA	5-SSOP	-40°C to 85°C	Active	ROHS3 Compliant
MIC5317-1.5YM5-T5	Microchip Technology	1.5V	150mA	6V	0.38V @ 150mA	39 µA	SOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
MIC5318-1.5YD5-TR	Microchip Technology	1.5V	300mA	6V	—	150 µA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
NCV8560SN150T1G	onsemi	1.5V	150mA	6V	—	170 µA	5-TSOP	-40°C to 125°C	Obsolete	ROHS3 Compliant
S-1132B15-M5T1U	ABLIC Inc.	1.5V	300mA	6.5V	0.58V @ 100mA	1 µA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
S-1167B15-M5T1U	ABLIC Inc.	1.5V	150mA	6.5V	0.58V @ 100mA	900 nA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
S-1315A15-M5T1U3	ABLIC Inc.	1.5V	200mA	5.5V	0.486V @ 200mA	1 µA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: LP5907MFX-1.5/NOPB (Texas Instruments)

The LP5907MFX-1.5/NOPB is the direct manufacturer-recommended substitute from Texas Instruments. It maintains the same 1.5V output voltage and SOT-23-5 package footprint while offering 250mA output current capability. The device is active in production, ROHS3 compliant, and supports the full -40°C to 125°C operating temperature range. The lower quiescent current (25 µA vs. 125 µA) provides improved power efficiency.

Alternative Direct Replacement: MIC5317-1.5YM5-T5 (Microchip Technology)

The MIC5317-1.5YM5-T5 delivers 150mA output current in a SOT-23-5 package with identical voltage specifications and full temperature range support (-40°C to 125°C). This part is active and ROHS3 compliant, offering a pin-compatible alternative with lower quiescent current (39 µA).

Alternative Direct Replacement: ADP121-AUJZ15R7 (Analog Devices Inc.)

The ADP121-AUJZ15R7 provides 150mA output current in a TSOT-23-5 package with identical voltage specifications and full temperature range support. This part is active and ROHS3 compliant, with the lowest quiescent current (21 µA) among direct replacements.

Enhanced Capacity Option: S-1315A15-M5T1U3 (ABLIC Inc.)

The S-1315A15-M5T1U3 offers 200mA output current in a SOT-23-5 package with 1.5V fixed output. This part is active and ROHS3 compliant, providing increased current headroom for applications requiring higher load capacity. Operating temperature range is -40°C to 85°C.

Note on Obsolete Parts:

The NCV8560SN150T1G (onsemi) is classified as obsolete despite ROHS3 compliance. While it meets electrical specifications, its obsolete status makes it unsuitable for new designs or long-term supply assurance.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with higher output current (200mA or 300mA) in place of the 150mA LP3984IMF-1.5?

A: Yes. Higher output current capability is a compatible substitution parameter. Parts rated for 200mA or 300mA will function correctly in applications designed for 150mA, as they provide additional current headroom without affecting voltage regulation or control characteristics.

Q: Are SOT-23-5 and TSOT-23-5 packages pin-compatible?

A: Both packages use identical pin configurations and footprints. TSOT-23-5 is a thinner variant of SOT-23-5 but maintains full pin compatibility for PCB assembly and electrical connection.

Q: What is the significance of the dropout voltage difference between the LP3984IMF-1.5 (0.12V) and substitute parts?

A: The LP3984IMF-1.5 has exceptionally low dropout voltage. Substitute parts with higher dropout voltages (0.25V to 0.7V) require proportionally higher input voltage headroom to maintain stable 1.5V output. Verify your input voltage supply can accommodate the substitute part's dropout specification.

Q: Why do some substitute parts have lower quiescent current?

A: Quiescent current represents the regulator's internal power consumption when no load is connected. Lower quiescent current (21 µA to 1 µA) indicates more efficient IC design, reducing standby power consumption in battery-powered or low-power applications.

Q: Is the LP3984IMF-1.5 RoHS non-compliance a concern for substitution?

A: The LP3984IMF-1.5 is RoHS non-compliant due to its obsolete status. All recommended substitute parts are ROHS3 compliant, meeting current environmental and regulatory requirements. Use ROHS3-compliant substitutes for new designs and long-term product support.

Q: Can I substitute a part with a narrower operating temperature range (−40°C to 85°C instead of −40°C to 125°C)?

A: Only if your application's maximum operating temperature does not exceed 85°C. The LP3984IMF-1.5 supports 125°C; substitutes with 85°C maximum ratings are suitable only for applications operating within this lower temperature ceiling.

Q: What is the difference between "Active" and "Obsolete" product status?

A: Active parts are in current production with guaranteed long-term availability and manufacturer support. Obsolete parts are no longer manufactured and have limited remaining inventory. For new designs and sustained production, select only active substitute parts.

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