LP3855EMP-5.0 Linear Voltage Regulator — Equivalent & Substitute Parts

Part Overview

The LP3855EMP-5.0 is a linear voltage regulator IC from Texas Instruments, classified as a Power Management (PMIC) component. It delivers a fixed 5V output at 1.5A in a surface-mount SOT-223-5 package. The device is currently marked as obsolete, making identification of active equivalent and substitute parts essential for ongoing production, maintenance, and design updates. This reference provides parametric equivalents and functional substitutes that maintain electrical and mechanical compatibility within the specified operating envelope.

Key Parameters

Parameter	Value
Manufacturer Part Number	LP3855EMP-5.0
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Package / Case	SOT-223-5 (TO-261-5, TO-261AB)
Output Configuration	Positive
Output Type	Fixed
Voltage - Output (Fixed)	5V
Voltage - Input (Max)	7V
Current - Output	1.5A
Voltage Dropout (Max)	0.44V @ 1.5A
Operating Temperature Range	-40°C to 125°C
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the LP3855EMP-5.0 are grouped based on strict electrical and mechanical parameter alignment:

Primary Substitution Criteria:

Fixed 5V output voltage
1.5A output current capability
Maximum input voltage of 7V
SOT-223-5 package compatibility
Surface-mount configuration
Operating temperature range -40°C to 125°C
Enable control feature
Over-current, over-temperature, and short-circuit protection

Grouping Logic:

Group 1 — Direct Parametric Equivalents (Identical Dropout Performance): LP3855EMP-5.0/NOPB, LP3855EMPX-5.0/NOPB, and LP3852EMP-5.0/NOPB maintain 0.44V maximum dropout at 1.5A, 3 mA quiescent current, and 10 mA maximum supply current. These parts are electrically interchangeable with the obsolete LP3855EMP-5.0.

Group 2 — Functional Equivalents (Relaxed Dropout Specification): LP3872EMP-5.0/NOPB and LP3875EMP-5.0/NOPB feature 0.55V maximum dropout at 1.5A, 5 mA quiescent current, and 15 mA maximum supply current. These parts meet the same output voltage and current requirements but with slightly higher power dissipation characteristics. They are suitable for applications where the relaxed dropout specification does not impact system performance.

All substitute parts maintain identical package geometry, pin configuration, and protection feature sets.

Parameter Comparison

Parameter	LP3855EMP-5.0	LP3852EMP-5.0/NOPB	LP3855EMP-5.0/NOPB	LP3855EMPX-5.0/NOPB	LP3872EMP-5.0/NOPB	LP3875EMP-5.0/NOPB
Manufacturer	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	National Semiconductor	Texas Instruments
Product Status	Obsolete	Active	Active	Active	Active	Active
Output Voltage (Fixed)	5V	5V	5V	5V	5V	5V
Output Current	1.5A	1.5A	1.5A	1.5A	1.5A	1.5A
Input Voltage (Max)	7V	7V	7V	7V	7V	7V
Voltage Dropout (Max)	0.44V @ 1.5A	0.44V @ 1.5A	0.44V @ 1.5A	0.44V @ 1.5A	0.55V @ 1.5A	0.55V @ 1.5A
Quiescent Current (Iq)	3 mA	3 mA	3 mA	3 mA	5 mA	5 mA
Supply Current (Max)	10 mA	10 mA	10 mA	10 mA	15 mA	15 mA
PSRR	73dB ~ 57dB (120Hz)	73dB ~ 57dB (120Hz)	73dB ~ 57dB (120Hz)	73dB ~ 57dB (120Hz)	73dB ~ 57dB (120Hz)	73dB ~ 57dB (120Hz)
Package / Case	SOT-223-5	SOT-223-5	SOT-223-5	SOT-223-5	SOT-223	SOT-223-5
Operating Temperature	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not specified	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Obsolete Part Elimination):

LP3855EMP-5.0/NOPB is the primary active equivalent. It maintains identical electrical specifications (0.44V dropout, 3 mA quiescent current) and is ROHS3 compliant, making it suitable for new designs and production restocking. This part is available in active status with 3374 units in stock.

LP3855EMPX-5.0/NOPB provides an alternative from the same manufacturer with identical performance characteristics and ROHS3 compliance. This variant is available with 868 units in stock.

LP3852EMP-5.0/NOPB is a functionally equivalent alternative from Texas Instruments with matching electrical performance and ROHS3 compliance. It is available in active status with 1781 units in stock.

For Applications with Relaxed Dropout Requirements:

LP3872EMP-5.0/NOPB (National Semiconductor) and LP3875EMP-5.0/NOPB (Texas Instruments) are suitable substitutes where the 0.55V dropout specification does not compromise system performance. Both maintain 1.5A output current and identical package geometry. LP3875EMP-5.0/NOPB is ROHS3 compliant with 2186 units in stock. LP3872EMP-5.0/NOPB is available with 1088 units in stock.

Compliance Considerations:

All active substitute parts are ROHS3 compliant or unaffected by REACH regulations. The obsolete LP3855EMP-5.0 is RoHS non-compliant; migration to any active equivalent ensures regulatory compliance for new production.

Frequently Asked Questions (FAQ)

Q: Can LP3855EMP-5.0/NOPB directly replace the obsolete LP3855EMP-5.0?

A: Yes. LP3855EMP-5.0/NOPB is the active equivalent with identical electrical specifications, package configuration, and pin assignment. The /NOPB suffix indicates lead-free (Pb-free) compliance. No circuit modifications are required.

Q: What is the difference between LP3855EMP-5.0/NOPB and LP3855EMPX-5.0/NOPB?

A: Both parts are from Texas Instruments with identical electrical performance (0.44V dropout, 3 mA quiescent current, 5V fixed output, 1.5A current). The X variant designation indicates a different manufacturing process or qualification level. Both are ROHS3 compliant and pin-compatible.

Q: Can I use LP3872EMP-5.0/NOPB or LP3875EMP-5.0/NOPB as substitutes?

A: Yes, if your application tolerates the higher dropout voltage (0.55V vs. 0.44V). These parts maintain the same 5V output, 1.5A current capability, and SOT-223 package. The increased quiescent current (5 mA vs. 3 mA) and supply current (15 mA vs. 10 mA) result in higher power dissipation. Verify that your power budget and thermal design accommodate these differences.

Q: Are all substitute parts available in the same package?

A: All substitute parts use SOT-223 or SOT-223-5 packages with identical pin configurations and mechanical footprints. LP3872EMP-5.0/NOPB is specified as SOT-223 (without the -5 designation), but maintains mechanical and electrical compatibility with SOT-223-5 devices.

Q: What is the impact of RoHS compliance on part selection?

A: The obsolete LP3855EMP-5.0 is RoHS non-compliant. All active substitutes (LP3855EMP-5.0/NOPB, LP3855EMPX-5.0/NOPB, LP3852EMP-5.0/NOPB, LP3875EMP-5.0/NOPB) are ROHS3 compliant. For new production and designs subject to RoHS regulations, use only ROHS3-compliant alternatives.

Q: Which substitute offers the best inventory availability?

A: LP3855EMP-5.0/NOPB has the highest inventory level at 3374 units in stock. LP3875EMP-5.0/NOPB is available with 2186 units, and LP3852EMP-5.0/NOPB with 1781 units. All three are suitable for immediate procurement.

Q: Can I mix different substitute parts in the same production batch?

A: Yes, provided all parts meet your electrical and thermal requirements. Parts within Group 1 (0.44V dropout) are electrically interchangeable. Parts within Group 2 (0.55V dropout) are interchangeable with each other but not with Group 1 without thermal re-analysis. Maintain consistent part selection within a single PCB assembly to avoid thermal design complications.

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