LP3855EMP-3.3 Equivalent & Substitute Parts

Part Overview

The LP3855EMP-3.3 is a linear voltage regulator IC from Texas Instruments, delivering a fixed 3.3V output at 1.5A in a SOT-223-5 surface mount package. This device is classified as obsolete, which necessitates identification of active equivalent alternatives for new designs and ongoing production requirements. The regulator incorporates enable control, over-current protection, over-temperature protection, and short-circuit protection, making it suitable for general-purpose 3.3V power supply applications requiring moderate current delivery.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Output Voltage (Fixed)	3.3V
Output Current	1.5A
Input Voltage (Max)	7V
Dropout Voltage (Max)	0.44V @ 1.5A
Quiescent Current	3 mA
Package	SOT-223-5
Operating Temperature Range	-40°C to 125°C
Protection Features	Over Current, Over Temperature, Short Circuit
Control Features	Enable
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the LP3855EMP-3.3 are grouped based on strict electrical and mechanical parameter matching. The primary substitution criteria are:

Core Matching Parameters:

Output voltage: 3.3V fixed
Output current capability: 1.5A
Input voltage maximum: 7V
Package type: SOT-223-5
Mounting type: Surface mount
Operating temperature range: -40°C to 125°C
Protection features: Over current, over temperature, short circuit
Control features: Enable function

Secondary Differentiation Parameters:

Dropout voltage (0.44V vs. 0.55V)
Quiescent current (3 mA vs. 5 mA vs. 9 mA)
Supply current maximum (10 mA vs. 15 mA)
Product status (Active vs. Last Time Buy vs. Obsolete)
RoHS compliance status
Packaging format (Tape & Reel vs. Cut Tape & Digi-Reel)

All listed substitutes maintain identical electrical performance for the primary output specifications and are pin-compatible within the SOT-223-5 package footprint.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage (Max)	Quiescent Current	Supply Current (Max)	Package	Product Status	RoHS Status
LP3855EMP-3.3	Texas Instruments	3.3V	1.5A	7V	0.44V @ 1.5A	3 mA	10 mA	SOT-223-5	Obsolete	Non-compliant
LP3852EMP-3.3	Texas Instruments	3.3V	1.5A	7V	0.44V @ 1.5A	3 mA	10 mA	SOT-223-5	Last Time Buy	ROHS3 Compliant
LP3852EMP-3.3/NOPB	Texas Instruments	3.3V	1.5A	7V	0.44V @ 1.5A	3 mA	10 mA	SOT-223-5	Active	ROHS3 Compliant
LP3855EMP-3.3/NOPB	Texas Instruments	3.3V	1.5A	7V	0.44V @ 1.5A	3 mA	10 mA	SOT-223-5	Active	ROHS3 Compliant
LP3872EMP-3.3/NOPB	Texas Instruments	3.3V	1.5A	7V	0.55V @ 1.5A	5 mA	15 mA	SOT-223-5	Active	ROHS3 Compliant
LP3872EMPX-3.3/NOPB	Texas Instruments	3.3V	1.5A	7V	0.55V @ 1.5A	5 mA	15 mA	SOT-223-5	Active	ROHS3 Compliant
LP3875EMP-3.3/NOPB	Texas Instruments	3.3V	1.5A	7V	0.55V @ 1.5A	5 mA	15 mA	SOT-223-5	Active	ROHS3 Compliant
LP3962EMP-3.3	Texas Instruments	3.3V	1.5A	7V	0.55V @ 1.5A	9 mA	15 mA	SOT-223-5	Last Time Buy	ROHS3 Compliant
LP3962EMP-3.3/NOPB	Texas Instruments	3.3V	1.5A	7V	0.55V @ 1.5A	9 mA	15 mA	SOT-223-5	Active	ROHS3 Compliant
LP3965EMP-3.3/NOPB	Texas Instruments	3.3V	1.5A	7V	0.55V @ 1.5A	9 mA	15 mA	SOT-223-5	Active	ROHS3 Compliant

Engineering Selection Recommendations

Tier 1 - Direct Replacement (Identical Electrical Performance):

LP3852EMP-3.3/NOPB and LP3855EMP-3.3/NOPB are the primary substitutes, offering identical dropout voltage (0.44V @ 1.5A) and quiescent current (3 mA) specifications. Both are Active status parts with ROHS3 compliance. LP3855EMP-3.3/NOPB maintains the original base part number designation. These are suitable for direct PCB substitution without design modification.

Tier 2 - Functional Equivalents (Acceptable Parameter Variance):

LP3872EMP-3.3/NOPB, LP3872EMPX-3.3/NOPB, LP3875EMP-3.3/NOPB, LP3962EMP-3.3/NOPB, and LP3965EMP-3.3/NOPB are functionally equivalent with acceptable parameter differences. These parts exhibit higher dropout voltage (0.55V @ 1.5A) and increased quiescent current (5 mA or 9 mA). All are Active status with ROHS3 compliance. Selection from this tier requires verification that the increased dropout voltage and quiescent current do not violate system power budget or thermal constraints.

Compliance Considerations:

All substitute parts carry ROHS3 compliance certification, addressing the non-compliant status of the original LP3855EMP-3.3. The /NOPB suffix indicates halogen-free lead-free construction, meeting modern environmental and manufacturing standards.

Inventory and Availability:

LP3872EMP-3.3/NOPB offers the highest inventory availability (55,342 units), followed by LP3852EMP-3.3/NOPB (2,200 units) and LP3855EMP-3.3/NOPB (2,396 units). Parts designated Last Time Buy (LP3852EMP-3.3, LP3962EMP-3.3) should be avoided for new designs requiring long-term supply assurance.

Frequently Asked Questions (FAQ)

Q: Can LP3872EMP-3.3/NOPB replace LP3855EMP-3.3 directly on the PCB?

A: Yes, LP3872EMP-3.3/NOPB is pin-compatible in the SOT-223-5 package. However, the increased dropout voltage (0.55V vs. 0.44V) and quiescent current (5 mA vs. 3 mA) must be evaluated against system power supply headroom and thermal design margins.

Q: What is the difference between LP3855EMP-3.3 and LP3855EMP-3.3/NOPB?

A: The /NOPB suffix indicates halogen-free, lead-free construction. Both maintain identical electrical specifications. LP3855EMP-3.3/NOPB is Active status with ROHS3 compliance, while the original LP3855EMP-3.3 is Obsolete and non-compliant.

Q: Why do some substitutes have higher quiescent current (9 mA vs. 3 mA)?

A: Quiescent current variation reflects different internal circuit implementations across the LP39xx regulator family. Higher quiescent current increases standby power consumption. Selection depends on application duty cycle and power budget constraints.

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

A: Substitute parts are available in Tape & Reel (TR) or Cut Tape & Digi-Reel (CT) formats. Verify packaging format compatibility with your procurement and assembly processes before selection.

Q: Which substitute offers the best long-term availability?

A: LP3852EMP-3.3/NOPB, LP3855EMP-3.3/NOPB, LP3872EMP-3.3/NOPB, LP3872EMPX-3.3/NOPB, LP3875EMP-3.3/NOPB, LP3962EMP-3.3/NOPB, and LP3965EMP-3.3/NOPB all carry Active product status, ensuring continued manufacturing and supply. Avoid Last Time Buy designations for new production designs.

Q: Is the dropout voltage difference between 0.44V and 0.55V significant?

A: The 0.11V difference is significant in low-headroom applications. If your input supply margin is less than 0.55V above the 3.3V output requirement, verify that Tier 2 substitutes maintain adequate regulation. Tier 1 substitutes (LP3852EMP-3.3/NOPB, LP3855EMP-3.3/NOPB) preserve the original 0.44V specification.

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