LP2981-33DBVRG4 Equivalent & Substitute Parts

Part Overview

The LP2981-33DBVRG4 is a linear voltage regulator IC from Texas Instruments designed to deliver a fixed 3.3V output at 100mA. This positive fixed output regulator operates across an input voltage range up to 16V with a maximum dropout voltage of 0.37V at full load. The device integrates over-current, over-temperature, and short-circuit protection, making it suitable for low-power applications requiring stable 3.3V regulation in space-constrained environments.

The LP2981-33DBVRG4 is currently listed as obsolete. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3.3V
Output Current	100mA
Input Voltage (Max)	16V
Dropout Voltage (Max)	0.37V @ 100mA
Quiescent Current	95 µA
PSRR	63dB (1kHz)
Package	SOT-23-5 (SC-74A)
Operating Temperature	-40°C to 125°C
Protection Features	Over Current, Over Temperature, Short Circuit
Control Features	Enable
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the LP2981-33DBVRG4 is determined by strict electrical and mechanical parameter matching:

Primary Substitution Criteria:

Fixed output voltage of 3.3V
Output current rating of 100mA minimum
Maximum input voltage of 16V or greater
Dropout voltage not exceeding 0.37V @ 100mA
SOT-23-5 package compatibility
Operating temperature range of -40°C to 125°C
Enable control feature
Over-current and over-temperature protection

Substitute Categories:

Manufacturer Recommended (Texas Instruments Active Parts): LP2981AIM5-3.3/NOPB, LP2981AIM5X-3.3/NOPB, and LP2981IM5X-3.3/NOPB meet all electrical specifications and are currently in active production status.

Parametric Equivalents (Texas Instruments): LP2981-33DBVR, LP2981-33DBVT, LP2981A-33DBVR, LP2981A-33DBVT, and LP2981IM5-3.3/NOPB provide identical electrical performance with variations in packaging format and product lifecycle status.

Cross-Manufacturer Equivalent (STMicroelectronics): LD2981ABM33TR from STMicroelectronics meets all core electrical parameters with minor variations in quiescent current (150 µA vs. 95 µA) and maximum supply current (2.6 mA vs. 1.7 mA), remaining functionally compatible for the specified application.

Parameter Comparison

Part Number	Manufacturer	Status	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage	Iq (µA)	Package	Inventory
LP2981-33DBVRG4	Texas Instruments	Obsolete	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	23,637 Pcs
LP2981AIM5-3.3/NOPB	Texas Instruments	Active	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	4,948 Pcs
LP2981AIM5X-3.3/NOPB	Texas Instruments	Active	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	7,272 Pcs
LP2981IM5X-3.3/NOPB	Texas Instruments	Active	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	12,302 Pcs
LP2981-33DBVR	Texas Instruments	Active	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	69,150 Pcs
LP2981-33DBVT	Texas Instruments	Last Time Buy	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	4,490 Pcs
LP2981A-33DBVR	Texas Instruments	Active	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	56,100 Pcs
LP2981A-33DBVT	Texas Instruments	Last Time Buy	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	1,900 Pcs
LP2981A-33DBVTG4	Texas Instruments	Discontinued at DiGi Electronics	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	23,637 Pcs
LP2981IM5-3.3/NOPB	Texas Instruments	Active	3.3V	100mA	16V	0.37V @ 100mA	95	SOT-23-5	18,400 Pcs
LD2981ABM33TR	STMicroelectronics	Active	3.3V	100mA	16V	0.375V @ 100mA	150	SOT-23-5	24,300 Pcs

Engineering Selection Recommendations

For New Designs and Production:

Select from active-status Texas Instruments parts: LP2981AIM5-3.3/NOPB, LP2981AIM5X-3.3/NOPB, LP2981IM5X-3.3/NOPB, LP2981-33DBVR, or LP2981A-33DBVR. These parts maintain full electrical equivalence to the obsolete LP2981-33DBVRG4 and carry ROHS3 compliance certification. LP2981-33DBVR offers the highest inventory availability at 69,150 units.

For Field Replacement and Legacy Support:

LP2981-33DBVR or LP2981A-33DBVR provide direct functional replacement with active production status and substantial stock levels. Parts marked "Last Time Buy" (LP2981-33DBVT, LP2981A-33DBVT) remain available but represent end-of-life inventory.

Cross-Manufacturer Alternative:

LD2981ABM33TR from STMicroelectronics is functionally compatible with identical output voltage, current rating, package, and operating temperature range. The quiescent current specification (150 µA vs. 95 µA) and maximum supply current (2.6 mA vs. 1.7 mA) represent minor parametric differences that do not affect functional compatibility in standard 3.3V regulation applications. This part is currently in active production with 24,300 units in stock.

All recommended substitutes maintain ROHS3 compliance and MSL-1 moisture sensitivity rating.

Frequently Asked Questions (FAQ)

Q: Can LP2981-33DBVR directly replace LP2981-33DBVRG4?

A: Yes. LP2981-33DBVR is a parametric equivalent with identical electrical specifications: 3.3V fixed output, 100mA current rating, 0.37V dropout voltage at 100mA, 95 µA quiescent current, and SOT-23-5 package. The primary difference is product status—LP2981-33DBVR is active production while LP2981-33DBVRG4 is obsolete.

Q: What is the difference between LP2981AIM5-3.3/NOPB and LP2981AIM5X-3.3/NOPB?

A: Both parts are manufacturer-recommended substitutes with identical electrical specifications and active production status. The difference lies in packaging format and supplier designation. Both meet all electrical and mechanical requirements for direct substitution.

Q: Is LD2981ABM33TR from STMicroelectronics a suitable replacement?

A: Yes, LD2981ABM33TR is functionally compatible. It delivers 3.3V at 100mA in SOT-23-5 package across the same -40°C to 125°C operating range. The quiescent current is 150 µA (versus 95 µA) and maximum supply current is 2.6 mA (versus 1.7 mA). These differences do not affect functional performance in standard 3.3V regulation applications.

Q: Why are some parts marked "Last Time Buy"?

A: Parts designated "Last Time Buy" (LP2981-33DBVT, LP2981A-33DBVT) represent end-of-life inventory from the manufacturer. While electrically equivalent and currently available, these parts will not be replenished. Active-status alternatives are recommended for new designs.

Q: Are all substitutes ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification and MSL-1 moisture sensitivity rating, matching the original LP2981-33DBVRG4 specifications.

Q: What packaging formats are available?

A: Substitute parts are available in Cut Tape (CT), Cut Tape & Digi-Reel (CT & Digi-Reel), and Tape & Reel (TR) formats. All maintain the SOT-23-5 package specification. Packaging selection depends on procurement volume and assembly requirements.

Q: Can I use these parts interchangeably in existing designs?

A: Yes. All listed substitutes maintain identical electrical performance and SOT-23-5 package compatibility, enabling direct board-level substitution without design modification.

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