LP3963ES-2.5 Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LP3963ES-2.5 is a linear voltage regulator IC from Texas Instruments, classified as a Power Management (PMIC) component. It delivers a fixed positive 2.5V output at 3A maximum current in a TO-263 (DDPAK-5) surface mount package. The main part is marked as "Not For New Designs," indicating it has reached end-of-life status. Finding equivalent or substitute parts is necessary for ongoing production support, legacy system maintenance, and design continuity where this regulator is already deployed.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	2.5V
Output Current	3A
Input Voltage (Max)	7V
Voltage Dropout (Max)	1.2V @ 3A
Quiescent Current	9 mA
Package Type	TO-263 (DDPAK-5)
Operating Temperature Range	-40°C to 125°C
Protection Features	Over Current, Over Temperature, Short Circuit
Control Features	Enable

Substitute Part Grouping Explanation

Substitution eligibility for the LP3963ES-2.5 is determined by the following critical parameters:

Fixed output voltage of 2.5V
Maximum output current of 3A
Maximum input voltage of 7V
TO-263 (DDPAK-5) package compatibility
Operating temperature range of -40°C to 125°C
Presence of Enable control feature and Over Current/Over Temperature/Short Circuit protection

Parts are grouped into two categories:

Direct Equivalents: Parts with identical electrical specifications and the same base product number variant (LP3963ES-2.5/NOPB). These are pin-compatible and functionally identical replacements.

Parametric Equivalents: Parts from the LP3853, LP3856, LP3873, and LP3876 series that meet all critical electrical requirements (2.5V output, 3A current, 7V max input, TO-263 package) but may differ in secondary parameters such as quiescent current, dropout voltage, or PSRR characteristics. These are functionally compatible for the same application space.

Parameter Comparison

Part Number	Manufacturer	Product Status	Dropout Voltage @ 3A	Quiescent Current	Supply Current (Max)	PSRR	RoHS Status	Inventory
LP3963ES-2.5	Texas Instruments	Not For New Designs	1.2V	9 mA	15 mA	—	RoHS Non-Compliant	1420 Pcs
LP3963ES-2.5/NOPB	Texas Instruments	Active	1.2V	9 mA	15 mA	—	ROHS3 Compliant	2200 Pcs
LP3853ES-2.5/NOPB	Texas Instruments	Active	0.6V	4 mA	10 mA	73dB ~ 57dB (120Hz)	ROHS3 Compliant	1087 Pcs
LP3856ES-2.5/NOPB	National Semiconductor	Active	0.6V	4 mA	10 mA	73dB ~ 57dB (120Hz)	Not Specified	1203 Pcs
LP3873ES-2.5/NOPB	National Semiconductor	Active	1.2V	9 mA	15 mA	73dB ~ 57dB (120Hz)	Not Specified	1175 Pcs
LP3876ES-2.5/NOPB	Texas Instruments	Active	1.2V	5 mA	15 mA	—	ROHS3 Compliant	1259 Pcs
LP3966ES-2.5/NOPB	Texas Instruments	Active	1.2V	9 mA	15 mA	—	ROHS3 Compliant	1058 Pcs
LP3853ES-2.5	Texas Instruments	Last Time Buy	0.6V	4 mA	10 mA	73dB ~ 57dB (120Hz)	ROHS3 Compliant	1200 Pcs

Engineering Selection Recommendations

For Active Production (Recommended Primary Choice): LP3963ES-2.5/NOPB is the direct equivalent with Active product status and ROHS3 compliance. It provides identical electrical performance to the original LP3963ES-2.5 with improved regulatory compliance and higher inventory availability (2200 pcs).

For Improved Power Efficiency: LP3853ES-2.5/NOPB and LP3853ES-2.5 offer superior performance characteristics with lower dropout voltage (0.6V vs. 1.2V), reduced quiescent current (4 mA vs. 9 mA), and specified PSRR (73dB ~ 57dB at 120Hz). Both are Active or Last Time Buy status with ROHS3 compliance. These are suitable when thermal management or battery life is a design priority.

For Dropout-Sensitive Applications: LP3856ES-2.5/NOPB provides the same low-dropout performance as LP3853 variants (0.6V @ 3A) with Active status and equivalent quiescent current (4 mA).

For Electrical Specification Matching: LP3873ES-2.5/NOPB and LP3876ES-2.5/NOPB maintain the original dropout voltage (1.2V) and quiescent current characteristics (9 mA and 5 mA respectively) with Active product status, ensuring minimal circuit redesign.

Compliance Considerations: All recommended substitutes except LP3856ES-2.5/NOPB and LP3873ES-2.5/NOPB have confirmed ROHS3 compliance status. The original LP3963ES-2.5 is RoHS non-compliant; migration to compliant variants is necessary for new production batches.

Frequently Asked Questions (FAQ)

Q: Can I directly replace LP3963ES-2.5 with LP3963ES-2.5/NOPB? A: Yes. LP3963ES-2.5/NOPB is the direct equivalent with identical electrical specifications, pin configuration, and package type (TO-263 DDPAK-5). The primary difference is improved RoHS3 compliance status and higher inventory availability.

Q: What is the difference between LP3853ES-2.5 and LP3853ES-2.5/NOPB? A: Both are parametric equivalents with identical electrical performance. LP3853ES-2.5/NOPB is Active status with confirmed ROHS3 compliance and Tube packaging. LP3853ES-2.5 is Last Time Buy status with unspecified packaging. For new designs, LP3853ES-2.5/NOPB is preferred.

Q: Will LP3853 variants work as drop-in replacements? A: Yes, electrically and mechanically. LP3853ES-2.5/NOPB and LP3853ES-2.5 are pin-compatible in the TO-263 package. However, they feature improved performance (lower dropout voltage of 0.6V vs. 1.2V and reduced quiescent current of 4 mA vs. 9 mA). Verify that your circuit design does not depend on the original dropout voltage specification before substitution.

Q: Are National Semiconductor parts (LP3856, LP3873) compatible? A: Yes. LP3856ES-2.5/NOPB and LP3873ES-2.5/NOPB are parametric equivalents with identical package type, output voltage, current rating, and protection features. Both are Active status. Confirm RoHS compliance requirements with your supply chain, as these parts do not have specified RoHS status in the provided data.

Q: What is the impact of different quiescent current values? A: Quiescent current ranges from 4 mA (LP3853, LP3856) to 9 mA (LP3963, LP3873, LP3966). In battery-powered or low-power standby applications, lower quiescent current reduces idle power consumption. In standard AC-powered applications, this difference is typically negligible.

Q: Can I use parts with different dropout voltages interchangeably? A: Mechanically yes, electrically it depends on your input voltage margin. The original LP3963ES-2.5 has 1.2V dropout. LP3853 and LP3856 variants have 0.6V dropout, requiring less input voltage headroom. If your circuit operates with tight input voltage margins below 3.7V (2.5V output + 1.2V dropout), verify that the substitute's dropout voltage is compatible with your actual input voltage range.

Q: What packaging options are available? A: All parts use TO-263 (DDPAK-5) surface mount package. Packaging format varies: Tube (LP3963ES-2.5/NOPB, LP3876ES-2.5/NOPB, LP3966ES-2.5/NOPB, LP3853ES-2.5/NOPB), Bulk (LP3856ES-2.5/NOPB, LP3873ES-2.5/NOPB), or unspecified (LP3853ES-2.5). Confirm packaging requirements with your procurement process.

Q: Which part should I choose for new designs? A: LP3963ES-2.5/NOPB for direct compatibility, or LP3853ES-2.5/NOPB for improved efficiency. Both are Active status with ROHS3 compliance and adequate inventory. LP3853ES-2.5/NOPB is preferred if lower power consumption or reduced thermal dissipation is beneficial to your application.

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