LP3855ESX-3.3 Equivalent & Substitute Parts

Part Overview

The LP3855ESX-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 1.5A in a TO-263 (DDPAK-5) surface mount package. The device is currently listed as obsolete, which necessitates identification of active equivalent and substitute parts for ongoing design support and procurement.

Substiute Parts

LP3855ESX-3.3

Texas InstrumentsIn Stock: 1615LP3855ESX-3.3 Datasheet

Current PartRFQ

LP3852ESX-3.3/NOPB

Texas InstrumentsIn Stock: 2415LP3852ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3855ESX-3.3/NOPB

National SemiconductorIn Stock: 1711LP3855ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3872ESX-3.3/NOPB

Texas InstrumentsIn Stock: 1623LP3872ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3875ESX-3.3/NOPB

National SemiconductorIn Stock: 1462LP3875ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3962ESX-3.3/NOPB

Texas InstrumentsIn Stock: 2327LP3962ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LP3965ESX-3.3/NOPB

National SemiconductorIn Stock: 2875LP3965ESX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LP3855ESX-3.3 are selected based on strict electrical and mechanical parameter matching. The following criteria determine substitution eligibility:

Core Matching Parameters:

• Output voltage: 3.3V fixed
• Output current capability: 1.5A
• Maximum input voltage: 7V
• Package type: TO-263 (DDPAK-5)
• Mounting type: Surface mount
• Output configuration: Positive fixed
• Number of regulators: 1
• Control features: Enable function
• Protection features: Over Current, Over Temperature, Short Circuit

Acceptable Variation Parameters:

• Voltage dropout: Up to 0.55V @ 1.5A (original: 0.38V @ 1.5A)
• Quiescent current: Up to 9 mA (original: 3 mA)
• Supply current (max): Up to 15 mA (original: 10 mA)
• PSRR: May vary or be unspecified
• RoHS compliance: May differ from original
• Product status: Active preferred over obsolete

All substitute parts maintain identical output voltage, current rating, input voltage limits, package configuration, and thermal operating range.

Parameter Comparison

Engineering Selection Recommendations

Tier 1 - Direct Replacement (Lowest Risk): LP3852ESX-3.3/NOPB is the primary substitute. It maintains identical electrical specifications (0.38V dropout, 3 mA quiescent current) while offering active product status and ROHS3 compliance. This part provides the most direct functional equivalence to the obsolete LP3855ESX-3.3.

Tier 2 - Functional Equivalent (Acceptable Variation): LP3872ESX-3.3/NOPB and LP3875ESX-3.3/NOPB are functionally equivalent with acceptable parameter variations. Dropout voltage increases to 0.55V and quiescent current to 5 mA. These parts are suitable for applications where the slightly higher dropout voltage does not impact system performance. Both are active products with ROHS3 compliance (Texas Instruments) or active status (National Semiconductor).

Tier 3 - Extended Equivalent (Maximum Allowable Variation): LP3962ESX-3.3/NOPB and LP3965ESX-3.3/NOPB represent the maximum allowable parameter variation within the substitute group. Dropout voltage is 0.55V and quiescent current is 9 mA. These parts are suitable only for applications with sufficient input voltage margin and where quiescent current consumption is not a limiting factor. Both are active products.

Compliance Considerations: For new designs requiring RoHS compliance, select from Texas Instruments parts (LP3852ESX-3.3/NOPB, LP3872ESX-3.3/NOPB, LP3962ESX-3.3/NOPB), all of which carry ROHS3 certification. National Semiconductor variants are active but do not specify RoHS status.

Frequently Asked Questions (FAQ)

Q: Can LP3852ESX-3.3/NOPB be used as a direct replacement for LP3855ESX-3.3? A: Yes. LP3852ESX-3.3/NOPB is electrically and mechanically identical to the obsolete LP3855ESX-3.3, with matching dropout voltage (0.38V @ 1.5A), quiescent current (3 mA), and package configuration (TO-263 DDPAK-5). It is an active product with ROHS3 compliance.

Q: What is the difference between the 0.38V and 0.55V dropout voltage variants? A: Dropout voltage determines the minimum voltage differential required between input and output for proper regulation. The original LP3855ESX-3.3 specifies 0.38V dropout. Variants with 0.55V dropout require 0.17V additional input voltage margin. This affects applications with tight input voltage budgets or low input voltage supplies.

Q: Are all substitute parts available in the same package? A: Yes. All substitute parts use the TO-263 (DDPAK-5) surface mount package with identical pinout and mechanical dimensions. PCB layout and footprint compatibility is maintained across all listed substitutes.

Q: What is the difference between Texas Instruments and National Semiconductor part numbers? A: Both manufacturers produce functionally equivalent parts within the LP38xx regulator family. Texas Instruments parts carry explicit ROHS3 certification. National Semiconductor variants are active products but do not specify RoHS compliance status. Electrical performance and package configuration are identical for equivalent model numbers.

Q: Can I use LP3962ESX-3.3/NOPB or LP3965ESX-3.3/NOPB if the original design used LP3855ESX-3.3? A: These parts are functionally equivalent but with increased quiescent current (9 mA vs. 3 mA) and higher dropout voltage (0.55V vs. 0.38V). They are suitable only if the application can tolerate these parameter variations. Verify that input voltage margin remains adequate with the higher dropout specification.

Q: What does the /NOPB suffix indicate? A: The /NOPB suffix indicates the part is supplied without lead-free plating on the leads. This designation is a packaging and manufacturing specification that does not affect electrical performance or RoHS compliance status.

Q: Are there inventory considerations when selecting a substitute? A: Yes. Inventory levels vary across substitutes. LP3852ESX-3.3/NOPB (2351 pcs), LP3962ESX-3.3/NOPB (2300 pcs), and LP3965ESX-3.3/NOPB (2783 pcs) have higher availability. Verify current stock status with your supplier before finalizing component selection.