LP3855ES-1.8 Linear Voltage Regulator — Equivalent & Substitute Parts

Part Overview

The LP3855ES-1.8 is a linear voltage regulator IC from Texas Instruments, delivering a fixed 1.8V output at 1.5A in a TO-263 (DDPAK-5) surface mount package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and design updates. The regulator includes integrated protection features for over-current, over-temperature, and short-circuit conditions, with an enable control input for power management applications.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Part Number	LP3855ES-1.8
Output Voltage (Fixed)	1.8V
Output Current	1.5A
Input Voltage (Max)	7V
Voltage Dropout (Max)	0.38V @ 1.5A
Quiescent Current	3 mA
Package	TO-263-6 (DDPAK-5)
Operating Temperature	-40°C to 125°C
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following critical parameters:

Fixed output voltage of 1.8V
Output current capability of 1.5A
Maximum input voltage of 7V or greater
TO-263 (DDPAK-5) package compatibility
Operating temperature range of -40°C to 125°C
Enable control feature
Over-current, over-temperature, and short-circuit protection

Substitute parts are grouped into two categories: direct equivalents from Texas Instruments with identical or superior electrical characteristics, and parametric equivalents from alternative manufacturers meeting the same functional requirements.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Voltage Dropout @ 1.5A	Quiescent Current	Input Voltage (Max)	Package	Product Status	RoHS Status
LP3855ES-1.8	Texas Instruments	1.8V	1.5A	0.38V	3 mA	7V	TO-263-6	Obsolete	Non-compliant
LP3855ES-1.8/NOPB	Texas Instruments	1.8V	1.5A	0.38V	3 mA	7V	TO-263-6	Active	ROHS3 Compliant
LP3852ES-1.8/NOPB	Texas Instruments	1.8V	1.5A	0.38V	3 mA	7V	TO-263-6	Active	ROHS3 Compliant
LP3872ES-1.8/NOPB	Texas Instruments	1.8V	1.5A	0.55V	5 mA	7V	TO-263-6	Active	ROHS3 Compliant
LP3875ES-1.8/NOPB	Texas Instruments	1.8V	1.5A	0.55V	5 mA	7V	TO-263-6	Active	ROHS3 Compliant
LP3962ES-1.8/NOPB	Texas Instruments	1.8V	1.5A	0.55V	9 mA	7V	TO-263-6	Active	ROHS3 Compliant
LP3965ES-1.8/NOPB	Texas Instruments	1.8V	1.5A	0.55V	9 mA	7V	TO-263-6	Active	ROHS3 Compliant
LP3872ES-1.8	Texas Instruments	1.8V	1.5A	0.55V	5 mA	7V	TO-263-6	Not For New Designs	Non-compliant
MCP1827-1802E/ET	Microchip Technology	1.8V	1.5A	0.6V	220 µA	6V	DDPAK-5	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: LP3855ES-1.8/NOPB

This part is the direct equivalent of the obsolete LP3855ES-1.8, offering identical electrical performance with active product status and ROHS3 compliance. It is the preferred choice for direct replacement in existing designs.

Secondary Recommendations: LP3852ES-1.8/NOPB, LP3872ES-1.8/NOPB, LP3875ES-1.8/NOPB

These Texas Instruments parts maintain the 1.8V fixed output and 1.5A current rating with active status and ROHS3 compliance. LP3852ES-1.8/NOPB matches the original dropout voltage specification. LP3872ES-1.8/NOPB and LP3875ES-1.8/NOPB feature slightly higher dropout voltages (0.55V) but remain functionally compatible for applications with adequate input voltage margin.

Alternative Manufacturer Option: MCP1827-1802E/ET

The Microchip MCP1827-1802E/ET provides equivalent functionality with active status and ROHS3 compliance. This part features a lower maximum input voltage (6V versus 7V) and significantly lower quiescent current (220 µA versus 3-9 mA), making it suitable for battery-powered or low-power applications. The dropout voltage is 0.6V at 1.5A. Additional control features include Power Good output and Under Voltage Lockout (UVLO).

Avoid: LP3872ES-1.8 (without /NOPB suffix)

This variant carries "Not For New Designs" status and RoHS non-compliance, making it unsuitable for new production.

Frequently Asked Questions (FAQ)

Q: Can I use LP3855ES-1.8/NOPB as a direct replacement for LP3855ES-1.8?

A: Yes. LP3855ES-1.8/NOPB is the active equivalent with identical electrical specifications, the same TO-263-6 package, and improved RoHS3 compliance. No circuit modifications are required.

Q: What is the difference between LP3852ES-1.8/NOPB and LP3872ES-1.8/NOPB?

A: Both deliver 1.8V at 1.5A in the same package. LP3852ES-1.8/NOPB maintains the original 0.38V dropout voltage, while LP3872ES-1.8/NOPB has 0.55V dropout. LP3852ES-1.8/NOPB is preferred if dropout voltage is critical to your design margin.

Q: Is the MCP1827-1802E/ET compatible with the original LP3855ES-1.8?

A: The MCP1827-1802E/ET meets the core functional requirements: 1.8V fixed output, 1.5A current, TO-263 package, and -40°C to 125°C operating range. However, the maximum input voltage is 6V (versus 7V), and quiescent current is significantly lower at 220 µA. Verify your input voltage does not exceed 6V and confirm that the additional Power Good and UVLO features do not conflict with your circuit design.

Q: Why do some parts have higher quiescent current?

A: Quiescent current varies by device architecture and internal circuitry. LP3962ES-1.8/NOPB and LP3965ES-1.8/NOPB draw 9 mA quiescent current compared to 3 mA for the original. This difference is acceptable for most applications but should be evaluated in battery-powered or ultra-low-power designs.

Q: Are all substitute parts RoHS3 compliant?

A: All recommended active parts (LP3855ES-1.8/NOPB, LP3852ES-1.8/NOPB, LP3872ES-1.8/NOPB, LP3875ES-1.8/NOPB, LP3962ES-1.8/NOPB, LP3965ES-1.8/NOPB, and MCP1827-1802E/ET) are ROHS3 compliant. The original LP3855ES-1.8 and LP3872ES-1.8 (without /NOPB) are not compliant and should not be used in new designs.

Q: Can I use these parts interchangeably in my PCB layout?

A: Yes. All substitute parts use the TO-263-6 or DDPAK-5 package with identical pinout and thermal characteristics. No PCB modifications are necessary for package compatibility.

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