LP3856ESX-3.3 Equivalent & Substitute Parts

Part Overview

The LP3856ESX-3.3 is a linear voltage regulator IC from Texas Instruments, classified as a Power Management (PMIC) component. It delivers a fixed 3.3V output at 3A maximum current in a TO-263 (DDPAK-5) surface mount package. The main part is currently listed as obsolete, making equivalent substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain identical electrical performance and mechanical compatibility to ensure direct replacement capability in existing circuit designs.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3.3V
Maximum Output Current	3A
Maximum Input Voltage	7V
Maximum Dropout Voltage	0.6V @ 3A
Quiescent Current (Iq)	4 mA
Package Type	TO-263 (DDPAK-5)
Operating Temperature Range	-40°C to 125°C
Control Features	Enable
Protection Features	Over Current, Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitute parts for the LP3856ESX-3.3 are grouped based on strict electrical and mechanical parameter alignment. The primary substitution criteria are:

Fixed output voltage of 3.3V
Maximum output current of 3A
Maximum input voltage of 7V
TO-263 (DDPAK-5) package compatibility
Enable control feature and integrated protection (Over Current, Over Temperature, Short Circuit)
Operating temperature range of -40°C to 125°C

Parts are further differentiated by dropout voltage specifications and quiescent current characteristics. The LP3856ESX-3.3/NOPB and LP3853ESX-3.3/NOPB maintain the original 0.6V dropout specification, while LP3873ESX-3.3/NOPB, LP3963ESX-3.3, LP3963ESX-3.3/NOPB, and LP3966ESX-3.3/NOPB feature a 1.2V dropout voltage with higher quiescent current (9 mA vs. 4 mA).

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage @ 3A	Quiescent Current	Supply Current (Max)	PSRR	Product Status	RoHS Status
LP3856ESX-3.3	Texas Instruments	3.3V	3A	7V	0.6V	4 mA	10 mA	73dB ~ 57dB (120Hz)	Obsolete	RoHS Non-Compliant
LP3853ESX-3.3/NOPB	Texas Instruments	3.3V	3A	7V	0.6V	4 mA	10 mA	73dB ~ 57dB (120Hz)	Active	ROHS3 Compliant
LP3856ESX-3.3/NOPB	Texas Instruments	3.3V	3A	7V	0.6V	4 mA	10 mA	73dB ~ 57dB (120Hz)	Active	ROHS3 Compliant
LP3873ESX-3.3/NOPB	Texas Instruments	3.3V	3A	7V	1.2V	9 mA	15 mA	73dB ~ 57dB (120Hz)	Active	ROHS3 Compliant
LP3963ESX-3.3	Texas Instruments	3.3V	3A	7V	1.2V	9 mA	15 mA	Not Specified	Last Time Buy	ROHS3 Compliant
LP3963ESX-3.3/NOPB	National Semiconductor	3.3V	3A	7V	1.2V	9 mA	15 mA	Not Specified	Active	Not Specified
LP3966ESX-3.3/NOPB	National Semiconductor	3.3V	3A	7V	1.2V	9 mA	15 mA	Not Specified	Active	Not Specified

Engineering Selection Recommendations

For direct replacement of the obsolete LP3856ESX-3.3, the LP3856ESX-3.3/NOPB is the primary equivalent, offering identical electrical specifications with active product status and ROHS3 compliance. The LP3853ESX-3.3/NOPB provides an alternative with matching performance characteristics and active availability.

For applications where higher dropout voltage and quiescent current are acceptable, the LP3873ESX-3.3/NOPB offers active status and full ROHS3 compliance. The LP3963ESX-3.3/NOPB and LP3966ESX-3.3/NOPB are functionally equivalent alternatives with active product status, though PSRR specifications are not provided for these parts.

The LP3963ESX-3.3 variant carries Last Time Buy status and should not be selected for new designs requiring long-term supply assurance.

Frequently Asked Questions (FAQ)

Q: Can LP3853ESX-3.3/NOPB directly replace LP3856ESX-3.3?

A: Yes. Both parts share identical electrical specifications: 3.3V fixed output, 3A maximum current, 0.6V dropout voltage at 3A, and 4 mA quiescent current. Both use the TO-263 (DDPAK-5) package. The primary difference is product status and RoHS compliance; LP3853ESX-3.3/NOPB is active and ROHS3 compliant.

Q: What is the difference between the 0.6V and 1.2V dropout voltage variants?

A: Parts with 0.6V dropout (LP3856ESX-3.3/NOPB, LP3853ESX-3.3/NOPB) require lower input-to-output voltage differential to maintain regulation at full 3A load. Parts with 1.2V dropout (LP3873ESX-3.3/NOPB, LP3963ESX-3.3/NOPB, LP3966ESX-3.3/NOPB) tolerate higher voltage differential but consume more quiescent current (9 mA vs. 4 mA). Selection depends on input voltage availability and power budget constraints.

Q: Are all substitute parts in the same package?

A: Yes. All listed substitute parts use the TO-263 (DDPAK-5) surface mount package, ensuring mechanical and thermal compatibility with existing PCB layouts.

Q: Which substitute part has the best availability and compliance status?

A: LP3856ESX-3.3/NOPB and LP3853ESX-3.3/NOPB both offer active product status and ROHS3 compliance. LP3873ESX-3.3/NOPB is also active and ROHS3 compliant. LP3963ESX-3.3 should be avoided due to Last Time Buy status.

Q: Can I use LP3963ESX-3.3/NOPB or LP3966ESX-3.3/NOPB as substitutes?

A: Yes, both are functionally equivalent with 3.3V output, 3A current, and 1.2V dropout voltage. However, PSRR specifications are not provided for these National Semiconductor variants. Verify PSRR performance requirements against your application before selection.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message