LP3871ES-1.8 Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LP3871ES-1.8 is a linear voltage regulator IC from Texas Instruments designed for positive fixed 1.8V output at 800mA in a TO-263 (DDPAK-5) surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The device provides regulated 1.8V output with integrated protection features including over-current, over-temperature, and short-circuit protection, suitable for applications requiring stable low-voltage power delivery.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Output Voltage (Fixed)	1.8V
Output Current	800mA
Input Voltage (Max)	7V
Voltage Dropout (Max)	0.35V @ 800mA
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)
Mounting Type	Surface Mount
Operating Temperature	-40°C ~ 125°C
Protection Features	Over Current, Over Temperature, Short Circuit
Control Features	Enable

Substitute Part Grouping Explanation

Substitution for the LP3871ES-1.8 is determined by the following critical parameters that must remain constant across all equivalent parts:

Output voltage: 1.8V fixed
Output current capability: 800mA
Input voltage maximum: 7V
Voltage dropout: 0.35V @ 800mA
Package type: TO-263 (DDPAK-5)
Mounting type: Surface Mount
Protection features: Over Current, Over Temperature, Short Circuit
Control features: Enable function

Parts meeting these specifications are classified as direct or parametric equivalents. Direct equivalents maintain identical electrical and mechanical specifications. Parametric equivalents meet the core functional requirements but may have minor variations in secondary parameters such as quiescent current or PSRR that do not affect primary circuit operation.

Parameter Comparison

Parameter	LP3871ES-1.8	LP3871ES-1.8/NOPB	LP3961ES-1.8/NOPB	LP3964ES-1.8/NOPB
Manufacturer	Texas Instruments	Texas Instruments	National Semiconductor	Texas Instruments
Product Status	Obsolete	Active	Active	Active
Output Voltage	1.8V	1.8V	1.8V	1.8V
Output Current	800mA	800mA	800mA	800mA
Input Voltage (Max)	7V	7V	7V	7V
Voltage Dropout (Max)	0.35V @ 800mA	0.35V @ 800mA	0.35V @ 800mA	0.35V @ 800mA
Quiescent Current (Iq)	5 mA	5 mA	9 mA	9 mA
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)	TO-263-6, D2PAK (5 Leads + Tab)	TO-263-6, D2PAK (5 Leads + Tab)	TO-263-6, D2PAK (5 Leads + Tab)
Operating Temperature	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C
RoHS Status	RoHS non-compliant	ROHS3 Compliant	Not specified	ROHS3 Compliant

Engineering Selection Recommendations

LP3871ES-1.8/NOPB is the direct equivalent replacement for the obsolete LP3871ES-1.8. This part maintains identical electrical specifications and is currently in active production status with ROHS3 compliance certification. It is the primary choice for new designs and obsolescence mitigation.

LP3964ES-1.8/NOPB is a parametric equivalent from Texas Instruments with active product status and ROHS3 compliance. It meets all core functional requirements with identical output voltage, current, dropout voltage, and package specifications. The quiescent current is 9 mA compared to 5 mA in the original part, representing a secondary parameter variation that does not affect primary regulator function.

LP3961ES-1.8/NOPB is a parametric equivalent from National Semiconductor with active product status. It meets all core functional requirements including output voltage, current, dropout voltage, and package specifications. The quiescent current is 9 mA, and PSRR data is not provided in the specification. This part is suitable for applications where National Semiconductor sourcing is acceptable.

Selection should prioritize LP3871ES-1.8/NOPB for direct replacement due to identical specifications and active production status. LP3964ES-1.8/NOPB and LP3961ES-1.8/NOPB are acceptable alternatives when the primary part is unavailable, provided the higher quiescent current does not impact system power budget requirements.

Frequently Asked Questions (FAQ)

Q: Can LP3964ES-1.8/NOPB replace LP3871ES-1.8 in existing designs?

A: Yes. LP3964ES-1.8/NOPB meets all critical electrical and mechanical specifications including output voltage, current rating, dropout voltage, and TO-263 package type. The quiescent current difference (9 mA vs 5 mA) must be evaluated against system power budget requirements.

Q: What is the difference between LP3871ES-1.8 and LP3871ES-1.8/NOPB?

A: LP3871ES-1.8/NOPB is the active production equivalent with identical electrical specifications. The /NOPB suffix indicates lead-free (no lead) and halogen-free packaging. LP3871ES-1.8 is obsolete; LP3871ES-1.8/NOPB is the current replacement.

Q: Are all substitute parts in the same package?

A: Yes. All listed parts use TO-263-6 (D2PAK with 5 Leads + Tab) surface mount package, ensuring mechanical and thermal compatibility in existing PCB layouts.

Q: Does quiescent current variation affect circuit operation?

A: Quiescent current affects system standby power consumption but does not impact regulator output voltage stability or load regulation performance. Applications with strict power budget constraints should account for the 4 mA difference between LP3871ES-1.8 (5 mA) and LP3964ES-1.8/NOPB or LP3961ES-1.8/NOPB (9 mA).

Q: Which substitute part has the best compliance status?

A: LP3871ES-1.8/NOPB and LP3964ES-1.8/NOPB both carry ROHS3 compliance certification. LP3961ES-1.8/NOPB compliance status is not specified in available documentation.

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