LP3966ESX-1.8 Linear Voltage Regulator — Equivalent & Substitute Parts

Part Overview

The LP3966ESX-1.8 is a linear voltage regulator IC manufactured by Texas Instruments, designed to deliver a fixed 1.8V output at 3A in a TO-263 (DDPAK-5) surface mount package. This device is classified as a Power Management IC (PMIC) and is currently in Last Time Buy status. Alternative equivalent parts are necessary due to product lifecycle transitions, inventory availability, and specific application requirements such as dropout voltage performance or quiescent current characteristics.

Key Parameters

Parameter	LP3966ESX-1.8
Manufacturer	Texas Instruments
Output Voltage (Fixed)	1.8V
Output Current	3A
Input Voltage (Max)	7V
Dropout Voltage @ 3A	1.2V
Quiescent Current	9 mA
Package	TO-263-6 (DDPAK-5)
Operating Temperature	-40°C to 125°C
Protection Features	Over Current, Over Temperature, Short Circuit
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the LP3966ESX-1.8 is determined by the following critical parameters:

Fixed output voltage of 1.8V
Output current capability of 3A (or higher)
Maximum input voltage of 7V or greater
TO-263 (DDPAK-5) package compatibility
Operating temperature range of -40°C to 125°C
Enable control feature
Protection against over current, over temperature, and short circuit conditions

Parts are grouped into two categories: parametric equivalents (matching all critical specifications) and manufacturer-recommended alternatives (meeting functional requirements with minor parameter variations).

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage @ Load	Quiescent Current	Package	Product Status
LP3966ESX-1.8	Texas Instruments	1.8V	3A	7V	1.2V @ 3A	9 mA	TO-263-6	Last Time Buy
LP3853ESX-1.8/NOPB	Texas Instruments	1.8V	3A	7V	0.6V @ 3A	4 mA	TO-263-6	Active
LP3856ESX-1.8/NOPB	Texas Instruments	1.8V	3A	7V	0.6V @ 3A	4 mA	TO-263-6	Active
LP3873ESX-1.8/NOPB	National Semiconductor	1.8V	3A	7V	1.2V @ 3A	9 mA	TO-263-6	Active
LP3876ESX-1.8/NOPB	Texas Instruments	1.8V	3A	7V	1.2V @ 3A	5 mA	TO-263-6	Active
LP3966ESX-1.8/NOPB	Texas Instruments	1.8V	3A	7V	1.2V @ 3A	9 mA	TO-263-6	Active
MIC39151-1.8WU	Microchip Technology	1.8V	1.5A	16V	0.5V @ 1.5A	Not specified	TO-263-6	Active
MIC39151-1.8WU-TR	Microchip Technology	1.8V	1.5A	16V	0.5V @ 1.5A	Not specified	TO-263-6	Active

Engineering Selection Recommendations

Direct Parametric Equivalents (3A Output Current)

LP3853ESX-1.8/NOPB and LP3856ESX-1.8/NOPB are parametric equivalents with identical 3A output current and TO-263 packaging. Both are Active status parts from Texas Instruments. These parts offer improved dropout voltage (0.6V vs. 1.2V) and lower quiescent current (4 mA vs. 9 mA), making them suitable for applications requiring reduced power dissipation. LP3853ESX-1.8/NOPB carries REACH Affected status, while LP3856ESX-1.8/NOPB is REACH Unaffected.

LP3876ESX-1.8/NOPB is an Active status Texas Instruments part with matching 3A output current and TO-263 packaging. It maintains the 1.2V dropout voltage specification and offers intermediate quiescent current (5 mA), providing a balance between the LP3966ESX-1.8 and the lower-current alternatives.

LP3873ESX-1.8/NOPB, manufactured by National Semiconductor, matches the LP3966ESX-1.8 in dropout voltage (1.2V) and quiescent current (9 mA) specifications while maintaining 3A output current and TO-263 packaging. This part is Active status and suitable for direct replacement in applications where these specific performance characteristics are required.

LP3966ESX-1.8/NOPB is the tape and reel packaged variant of the main part, maintaining identical electrical specifications and Active product status.

Manufacturer-Recommended Alternative (1.5A Output Current)

MIC39151-1.8WU and MIC39151-1.8WU-TR are Microchip Technology parts with reduced output current (1.5A vs. 3A) and higher maximum input voltage (16V vs. 7V). These parts are suitable only for applications where the 1.5A output current is sufficient. Both variants are Active status and ROHS3 compliant. MIC39151-1.8WU is supplied in Tube packaging, while MIC39151-1.8WU-TR is supplied in Tape & Reel packaging.

Frequently Asked Questions (FAQ)

Q: Can LP3853ESX-1.8/NOPB or LP3856ESX-1.8/NOPB be used as direct replacements for LP3966ESX-1.8?

A: Yes. Both parts deliver 1.8V at 3A in TO-263 packaging with identical input voltage ratings and operating temperature ranges. The primary differences are improved dropout voltage (0.6V vs. 1.2V) and lower quiescent current (4 mA vs. 9 mA), which reduce power dissipation and heat generation. These characteristics make them suitable for direct substitution in most applications.

Q: What is the difference between LP3876ESX-1.8/NOPB and LP3853ESX-1.8/NOPB?

A: Both parts maintain 1.8V output at 3A in TO-263 packaging. LP3876ESX-1.8/NOPB has a quiescent current of 5 mA (between LP3966ESX-1.8 at 9 mA and LP3853ESX-1.8/NOPB at 4 mA) and maintains the 1.2V dropout voltage of the original part. LP3853ESX-1.8/NOPB offers the lowest quiescent current (4 mA) and lowest dropout voltage (0.6V). Selection depends on whether the application prioritizes lower quiescent current or maintains the original dropout voltage specification.

Q: Can MIC39151-1.8WU replace LP3966ESX-1.8?

A: MIC39151-1.8WU is suitable only if the application requires a maximum output current of 1.5A or less. The part delivers 1.8V output in TO-263 packaging with superior dropout voltage (0.5V) and higher maximum input voltage (16V). It is not suitable for applications requiring the full 3A output current of the LP3966ESX-1.8.

Q: What is the difference between MIC39151-1.8WU and MIC39151-1.8WU-TR?

A: Both parts are electrically identical with 1.8V output at 1.5A maximum current. The difference is packaging: MIC39151-1.8WU is supplied in Tube packaging, while MIC39151-1.8WU-TR is supplied in Tape & Reel packaging. Selection depends on assembly process requirements and inventory management preferences.

Q: Why is LP3873ESX-1.8/NOPB listed as a substitute if it is manufactured by National Semiconductor?

A: LP3873ESX-1.8/NOPB matches the LP3966ESX-1.8 in all critical electrical specifications: 1.8V output, 3A output current, 1.2V dropout voltage, 9 mA quiescent current, and TO-263 packaging. It is Active status and suitable for direct replacement. Manufacturer diversity provides supply chain flexibility and alternative sourcing options.

Q: Are all substitute parts ROHS3 compliant?

A: All listed substitute parts are ROHS3 compliant. The LP3966ESX-1.8 is ROHS3 compliant. All Texas Instruments and Microchip Technology alternatives listed are ROHS3 compliant. LP3873ESX-1.8/NOPB RoHS status is not specified in the provided data.

Q: What should I consider when selecting between LP3853ESX-1.8/NOPB and LP3876ESX-1.8/NOPB?

A: Both parts are Active status Texas Instruments regulators with 1.8V output at 3A. LP3853ESX-1.8/NOPB offers the lowest quiescent current (4 mA) and lowest dropout voltage (0.6V), minimizing power dissipation. LP3876ESX-1.8/NOPB provides intermediate quiescent current (5 mA) while maintaining the original 1.2V dropout voltage. Selection depends on whether the application prioritizes maximum efficiency (LP3853ESX-1.8/NOPB) or maintains the original dropout voltage specification (LP3876ESX-1.8/NOPB).

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