LP3981IMM-2.5 Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LP3981IMM-2.5 is a linear voltage regulator IC from Texas Instruments designed for positive fixed 2.5V output applications with 300mA current capacity in an 8-VSSOP surface mount package. This device is classified as "Not For New Designs," indicating it has been superseded in the product lifecycle. Identifying equivalent and substitute parts is necessary for legacy system support, design continuity, and procurement flexibility when the primary part becomes unavailable or when design requirements favor alternative variants with improved compliance status.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Output Voltage (Fixed)	2.5V
Output Current	300mA
Input Voltage (Max)	6V
Voltage Dropout (Max)	0.2V @ 300mA
Package Type	8-VSSOP (8-TSSOP, 8-MSOP)
Mounting Type	Surface Mount
Operating Temperature Range	-40°C to 125°C
Control Features	Enable
Protection Features	Over Current, Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitute parts for the LP3981IMM-2.5 are identified based on strict parametric equivalence across the following critical criteria:

Output voltage configuration: Positive fixed 2.5V
Output current capacity: 300mA
Maximum input voltage: 6V
Voltage dropout specification: 0.2V @ 300mA
Package type: 8-VSSOP surface mount
Operating temperature range: -40°C to 125°C
Control and protection features: Enable function with Over Current, Over Temperature, and Short Circuit protection

The identified substitutes maintain identical electrical specifications and mechanical compatibility, differing only in product lifecycle status and compliance certifications. All substitute parts are manufactured by Texas Instruments and share the same base product number LP3981.

Parameter Comparison

Parameter	LP3981IMM-2.5	LP3981IMM-2.5/NOPB	LP3981IMMX-2.5/NOPB
Manufacturer	Texas Instruments	Texas Instruments	Texas Instruments
Output Voltage	2.5V	2.5V	2.5V
Output Current	300mA	300mA	300mA
Input Voltage (Max)	6V	6V	6V
Voltage Dropout (Max)	0.2V @ 300mA	0.2V @ 300mA	0.2V @ 300mA
Quiescent Current	120 µA	120 µA	120 µA
PSRR	50dB ~ 55dB (1kHz ~ 10kHz)	50dB ~ 55dB (1kHz ~ 10kHz)	50dB ~ 55dB (1kHz ~ 10kHz)
Package Type	8-VSSOP	8-VSSOP	8-VSSOP
Operating Temperature	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C
Product Status	Not For New Designs	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

For new designs and applications requiring regulatory compliance, LP3981IMM-2.5/NOPB or LP3981IMMX-2.5/NOPB are the preferred selections. Both substitute parts carry Active product status and ROHS3 compliance certification, ensuring long-term availability and adherence to environmental regulations.

The LP3981IMM-2.5 remains suitable for legacy system maintenance and repair applications where the original part specification is required. However, the non-compliant RoHS status and "Not For New Designs" classification restrict its use in new product development.

LP3981IMM-2.5/NOPB and LP3981IMMX-2.5/NOPB are electrically and mechanically interchangeable with the original part. Selection between these two active variants depends on procurement availability and inventory requirements, as both meet identical functional and compliance specifications.

Frequently Asked Questions (FAQ)

Q: Can LP3981IMM-2.5/NOPB be used as a direct replacement for LP3981IMM-2.5?

A: Yes. Both parts are parametrically equivalent across all electrical specifications, output voltage, current capacity, dropout voltage, and package type. The primary differences are product lifecycle status and RoHS compliance. LP3981IMM-2.5/NOPB is Active and ROHS3 compliant, making it suitable for new designs.

Q: What is the difference between LP3981IMM-2.5/NOPB and LP3981IMMX-2.5/NOPB?

A: Both parts are electrically and mechanically identical with matching specifications for output voltage, current, dropout voltage, and operating temperature range. Both are Active products with ROHS3 compliance. The designation difference reflects internal Texas Instruments product coding; both are suitable for equivalent applications.

Q: Are all three parts compatible with the same PCB layout?

A: Yes. All three parts use the 8-VSSOP package type with identical pin configuration, spacing, and mechanical dimensions. PCB layouts designed for any variant are compatible with the others without modification.

Q: Why is the original LP3981IMM-2.5 marked "Not For New Designs"?

A: This classification indicates the part has been superseded in Texas Instruments' product lifecycle. Active alternatives with improved compliance certifications are available. Existing designs using this part may continue operation, but new product development should utilize the Active variants.

Q: What compliance certifications apply to the substitute parts?

A: Both LP3981IMM-2.5/NOPB and LP3981IMMX-2.5/NOPB carry ROHS3 compliance certification and REACH Unaffected status. Both have Moisture Sensitivity Level 1 (Unlimited) and are classified under ECCN EAR99 for export purposes.

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