LP3873ESX-5.0 Linear Voltage Regulator IC Equivalent & Substitute Parts

Part Overview

The LP3873ESX-5.0 is a linear voltage regulator IC from Texas Instruments designed for positive fixed 5V output applications with 3A current capacity in a TO-263 (DDPAK-5) surface mount package. This part is classified as obsolete, which necessitates identification of active equivalent alternatives for new designs and ongoing production requirements. Substitute parts must maintain identical electrical performance characteristics and package compatibility to ensure direct replacement capability in existing circuit designs.

Key Parameters

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

Substitute Part Grouping Explanation

Substitution eligibility for the LP3873ESX-5.0 is determined by the following critical parameters:

Output voltage specification (5V fixed)
Maximum output current rating (3A minimum)
Input voltage tolerance (7V maximum)
Package configuration (TO-263 DDPAK-5)
Protection feature set (Over Current, Over Temperature, Short Circuit)
Operating temperature range (-40°C to 125°C)

Parts meeting all these criteria are classified as parametric equivalents. Secondary considerations include voltage dropout characteristics, quiescent current, and product status (active vs. obsolete). The substitute parts identified—LP3853ESX-5.0/NOPB, LP3856ESX-5.0/NOPB, and LP3873ESX-5.0/NOPB—satisfy all primary substitution requirements and are available in active product status with improved compliance certifications.

Parameter Comparison

Parameter	LP3873ESX-5.0	LP3853ESX-5.0/NOPB	LP3856ESX-5.0/NOPB	LP3873ESX-5.0/NOPB
Manufacturer	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments
Output Voltage	5V	5V	5V	5V
Output Current	3A	3A	3A	3A
Input Voltage (Max)	7V	7V	7V	7V
Voltage Dropout (Max)	1.2V @ 3A	0.6V @ 3A	0.6V @ 3A	1.2V @ 3A
Quiescent Current	9 mA	4 mA	4 mA	9 mA
Package	TO-263 (DDPAK-5)	TO-263 (DDPAK-5)	TO-263 (DDPAK-5)	TO-263 (DDPAK-5)
Operating Temperature	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C
Product Status	Obsolete	Active	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

All three substitute parts—LP3853ESX-5.0/NOPB, LP3856ESX-5.0/NOPB, and LP3873ESX-5.0/NOPB—are active products with ROHS3 compliance certification, making them suitable replacements for the obsolete LP3873ESX-5.0. The LP3873ESX-5.0/NOPB provides direct electrical equivalence with identical voltage dropout and quiescent current specifications. The LP3853ESX-5.0/NOPB and LP3856ESX-5.0/NOPB offer improved performance characteristics with reduced voltage dropout (0.6V vs. 1.2V) and lower quiescent current (4 mA vs. 9 mA), resulting in decreased power dissipation and improved thermal performance in applications where these parameters are beneficial. All parts maintain identical package configuration and protection feature sets, ensuring mechanical and functional compatibility in existing PCB layouts.

Frequently Asked Questions (FAQ)

Q: Can LP3853ESX-5.0/NOPB or LP3856ESX-5.0/NOPB be used as direct replacements for LP3873ESX-5.0?

A: Yes. Both parts meet all primary substitution criteria: identical 5V output, 3A current rating, 7V maximum input voltage, TO-263 DDPAK-5 package, and complete protection feature set. The reduced voltage dropout and quiescent current represent performance improvements rather than compatibility limitations.

Q: What is the significance of the voltage dropout difference between LP3873ESX-5.0 and LP3853ESX-5.0/NOPB?

A: Voltage dropout determines the minimum input-to-output voltage differential required for proper regulation. The LP3853ESX-5.0/NOPB requires only 0.6V dropout compared to 1.2V for the LP3873ESX-5.0, allowing operation with lower input voltages and reducing power dissipation in the regulator.

Q: Are all substitute parts available in the same packaging format?

A: Yes. All substitute parts are supplied in TO-263 (DDPAK-5) surface mount package configuration with identical pinout and thermal characteristics, ensuring direct PCB compatibility without layout modifications.

Q: What is the difference between LP3873ESX-5.0 and LP3873ESX-5.0/NOPB?

A: The primary difference is product status and compliance certification. LP3873ESX-5.0 is obsolete and RoHS non-compliant, while LP3873ESX-5.0/NOPB is an active product with ROHS3 compliance. The "/NOPB" designation indicates lead-free solder ball construction. Electrical specifications remain identical.

Q: Which substitute part should be selected for new designs?

A: For new designs, any of the three active substitute parts are acceptable. LP3873ESX-5.0/NOPB provides direct electrical equivalence. LP3853ESX-5.0/NOPB and LP3856ESX-5.0/NOPB offer superior performance with lower dropout voltage and quiescent current, making them preferable for power-sensitive or thermally constrained applications.

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