LP3963ESX-3.3 Equivalent & Substitute Parts

Part Overview

The LP3963ESX-3.3 is a linear voltage regulator IC from Texas Instruments, delivering a fixed 3.3V output at 3A in a TO-263 (DDPAK-5) surface mount package. This device is classified as Last Time Buy, indicating end-of-life status. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain flexibility, and support long-term production requirements for applications requiring 3.3V regulation at 3A output capacity.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3.3V
Output Current	3A
Input Voltage (Max)	7V
Voltage Dropout (Max)	1.2V @ 3A
Quiescent Current (Iq)	9 mA
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)
Operating Temperature Range	-40°C ~ 125°C
Protection Features	Over Current, Over Temperature, Short Circuit
Control Features	Enable
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitute parts for the LP3963ESX-3.3 are classified based on strict electrical and mechanical parameter alignment:

Direct Manufacturer Equivalent:

LP3963ESX-3.3/NOPB (National Semiconductor) — Identical electrical specifications and package configuration. Differs only in packaging format (Bulk vs. Cut Tape).

Parametric Equivalents:

LP3853ESX-3.3/NOPB, LP3856ESX-3.3/NOPB, LP3873ESX-3.3/NOPB, LP3966ESX-3.3/NOPB — All maintain the same output voltage (3.3V), output current (3A), input voltage maximum (7V), package type (TO-263 DDPAK-5), operating temperature range (-40°C ~ 125°C), and protection features (Over Current, Over Temperature, Short Circuit).

Substitution eligibility is determined by:

Fixed output voltage of 3.3V
Output current rating of 3A
Maximum input voltage of 7V
TO-263 (DDPAK-5) package compatibility
Enable control feature
Operating temperature range of -40°C ~ 125°C
Identical protection feature set

Parameter Comparison

Part Number	Manufacturer	Product Status	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage @ 3A	Quiescent Current	Supply Current (Max)	Package	Inventory (Pcs)
LP3963ESX-3.3	Texas Instruments	Last Time Buy	3.3V	3A	7V	1.2V	9 mA	15 mA	TO-263 (DDPAK-5)	1456
LP3963ESX-3.3/NOPB	National Semiconductor	Active	3.3V	3A	7V	1.2V	9 mA	15 mA	TO-263 (DDPAK-5)	1403
LP3853ESX-3.3/NOPB	Texas Instruments	Active	3.3V	3A	7V	0.6V	4 mA	10 mA	TO-263 (DDPAK-5)	10300
LP3856ESX-3.3/NOPB	Texas Instruments	Active	3.3V	3A	7V	0.6V	4 mA	10 mA	TO-263 (DDPAK-5)	1417
LP3873ESX-3.3/NOPB	Texas Instruments	Active	3.3V	3A	7V	1.2V	9 mA	15 mA	TO-263 (DDPAK-5)	1895
LP3966ESX-3.3/NOPB	National Semiconductor	Active	3.3V	3A	7V	1.2V	9 mA	15 mA	TO-263 (DDPAK-5)	1992

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical Performance): LP3963ESX-3.3/NOPB (National Semiconductor) is the primary direct equivalent. Both the original part and this substitute maintain identical dropout voltage (1.2V @ 3A), quiescent current (9 mA), and supply current specifications (15 mA max). Product status is Active, ensuring ongoing availability. Selection between Cut Tape and Bulk packaging depends on procurement volume requirements.

For Enhanced Performance (Lower Dropout, Reduced Quiescent Current): LP3853ESX-3.3/NOPB and LP3856ESX-3.3/NOPB offer improved electrical characteristics with 0.6V dropout voltage and 4 mA quiescent current, reducing power dissipation and thermal load. Both are Active products from Texas Instruments with substantial inventory availability (10300 and 1417 units respectively). These parts are suitable for applications where lower power consumption or reduced thermal management is beneficial.

For Dropout Voltage Matching: LP3873ESX-3.3/NOPB and LP3966ESX-3.3/NOPB maintain the original 1.2V dropout specification and 9 mA quiescent current, providing electrical equivalence to the LP3963ESX-3.3. Both are Active products with adequate inventory (1895 and 1992 units respectively).

All substitute parts are ROHS3 compliant, REACH unaffected, and rated for -40°C ~ 125°C operation, meeting standard industrial compliance requirements.

Frequently Asked Questions (FAQ)

Q: Can LP3853ESX-3.3/NOPB replace LP3963ESX-3.3 in existing designs? A: Yes. Both parts deliver 3.3V at 3A in TO-263 (DDPAK-5) packages with identical input voltage ratings (7V max) and operating temperature ranges (-40°C ~ 125°C). LP3853ESX-3.3/NOPB offers superior performance with lower dropout voltage (0.6V vs. 1.2V) and reduced quiescent current (4 mA vs. 9 mA), making it a direct functional replacement with improved efficiency.

Q: What is the difference between LP3963ESX-3.3 and LP3963ESX-3.3/NOPB? A: Both parts are electrically identical with matching output voltage (3.3V), output current (3A), dropout voltage (1.2V @ 3A), and quiescent current (9 mA). The primary difference is packaging format: LP3963ESX-3.3 is supplied in Cut Tape (CT) & Digi-Reel format, while LP3963ESX-3.3/NOPB is supplied in Bulk packaging. Selection depends on procurement and assembly requirements.

Q: Are all substitute parts in the same package? A: Yes. All listed substitute parts use the TO-263-6 (D2PAK with 5 Leads + Tab) package, ensuring mechanical and electrical pin compatibility for direct PCB substitution without layout modifications.

Q: Why is LP3963ESX-3.3 marked as Last Time Buy? A: Last Time Buy status indicates the original part is being discontinued. Identifying and qualifying substitute parts ensures design continuity and supply chain resilience for ongoing production and field support.

Q: Which substitute offers the best power efficiency? A: LP3853ESX-3.3/NOPB and LP3856ESX-3.3/NOPB provide the lowest quiescent current (4 mA) and dropout voltage (0.6V @ 3A), resulting in reduced power dissipation and improved thermal performance compared to the original LP3963ESX-3.3 specification (9 mA quiescent, 1.2V dropout).

Q: Are all parts RoHS and REACH compliant? A: Yes. All listed parts are ROHS3 compliant and REACH unaffected, meeting standard environmental and regulatory requirements for industrial and commercial applications.

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