LP3981IMM-3.3 Equivalent & Substitute Parts

Part Overview

The LP3981IMM-3.3 is a linear voltage regulator IC from Texas Instruments designed for positive fixed 3.3V output applications. This device delivers 300mA output current in an 8-VSSOP surface mount package and includes integrated protection features for over-current, over-temperature, and short-circuit conditions. The main part number is currently in Last Time Buy status, making equivalent and substitute parts essential for ongoing design support and procurement planning. Alternative part numbers and cross-compatible regulators from other manufacturers provide continuity for production and new designs.

Substiute Parts

LP3981IMM-3.3

Texas InstrumentsIn Stock: 17446LP3981IMM-3.3 Datasheet

Current PartRFQ

LP3981IMM-3.3/NOPB

Texas InstrumentsIn Stock: 16358LP3981IMM-3.3/NOPB Datasheet

DirectRFQ

LP3981IMMX-3.3/NOPB

Texas InstrumentsIn Stock: 16452LP3981IMMX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

NCP3335ADM330R2G

onsemiIn Stock: 1308NCP3335ADM330R2G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LP3981IMM-3.3 are classified into two categories based on electrical and mechanical compatibility:

Direct Equivalents (Same Manufacturer - Texas Instruments): LP3981IMM-3.3/NOPB and LP3981IMMX-3.3/NOPB are direct equivalents with identical electrical specifications and package footprints. These parts differ only in packaging format (Tape & Reel vs. Cut Tape) and product status. Substitution is valid when the output voltage (3.3V fixed), output current (300mA), input voltage rating (6V max), dropout voltage (0.2V @ 300mA), protection features, and package dimensions remain unchanged.

Parametric Equivalent (Cross-Manufacturer - onsemi): NCP3335ADM330R2G from onsemi is a parametric equivalent with the same 3.3V fixed output voltage, identical package footprint (8-MSOP), and compatible surface mount mounting type. This part provides higher output current capability (500mA vs. 300mA) and higher input voltage rating (16V vs. 6V), making it suitable for applications requiring greater current headroom. The key substitution criteria are: fixed 3.3V output, 8-MSOP package compatibility, surface mount technology, and positive output configuration.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Pin-for-Pin Compatible): LP3981IMM-3.3/NOPB and LP3981IMMX-3.3/NOPB are recommended when the original LP3981IMM-3.3 reaches end-of-life. Both parts maintain identical electrical performance and package footprint. Selection between these two depends on procurement packaging requirements: LP3981IMM-3.3/NOPB is supplied in Tape & Reel format for automated assembly, while LP3981IMMX-3.3/NOPB is also available in Tape & Reel. Both parts carry Active product status and ROHS3 compliance, ensuring long-term availability and regulatory compliance.

For Enhanced Performance Applications: NCP3335ADM330R2G from onsemi is suitable when designs require higher output current capacity (500mA vs. 300mA) or higher input voltage tolerance (16V vs. 6V). This part maintains the same 3.3V fixed output voltage and 8-MSOP package footprint, ensuring PCB compatibility. The trade-off is a reduced operating temperature upper limit (85°C vs. 125°C) and higher quiescent current (190 µA vs. 120 µA). This part is recommended only when the application's current and voltage requirements exceed the LP3981IMM-3.3 specifications and the lower temperature rating is acceptable.

Frequently Asked Questions (FAQ)

Q: Can LP3981IMM-3.3/NOPB be used as a direct replacement for LP3981IMM-3.3? A: Yes. Both parts have identical electrical specifications, output voltage (3.3V), output current (300mA), input voltage rating (6V), dropout voltage (0.2V @ 300mA), and package footprint (8-MSOP). The difference is packaging format and product status. LP3981IMM-3.3/NOPB is in Active status, making it the preferred choice for new designs and ongoing production.

Q: What is the difference between LP3981IMMX-3.3/NOPB and LP3981IMM-3.3/NOPB? A: Both parts are electrically identical with the same 3.3V output, 300mA current rating, and 8-MSOP package. The suffix variation (IMMX vs. IMM) indicates different manufacturing process nodes or internal design revisions, but all electrical and mechanical parameters remain unchanged. Both are suitable for direct substitution.

Q: Can NCP3335ADM330R2G replace LP3981IMM-3.3 in all applications? A: NCP3335ADM330R2G is a parametric equivalent suitable for applications where higher output current (500mA) or higher input voltage (16V) is beneficial. However, it has a lower maximum operating temperature (85°C vs. 125°C) and higher quiescent current (190 µA vs. 120 µA). Substitution is valid only when the application does not require the full 125°C temperature range and can tolerate the increased quiescent current.

Q: Are all substitute parts ROHS3 compliant? A: Yes. LP3981IMM-3.3, LP3981IMM-3.3/NOPB, LP3981IMMX-3.3/NOPB, and NCP3335ADM330R2G are all ROHS3 compliant with MSL rating of 1 (Unlimited), meeting regulatory requirements for industrial and commercial applications.

Q: What is the package compatibility between these parts? A: All parts use the 8-TSSOP or 8-MSOP package with 0.118" width and 3.00mm body width. The footprint is identical across all substitute parts, allowing direct PCB layout reuse without redesign.

Q: Why is LP3981IMM-3.3 marked as Last Time Buy? A: Last Time Buy status indicates that Texas Instruments is discontinuing this specific part number. LP3981IMM-3.3/NOPB and LP3981IMMX-3.3/NOPB are active alternatives from the same manufacturer with identical specifications, ensuring design continuity without performance impact.