LP2981IM5X-3.0 Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LP2981IM5X-3.0 is a micropower linear voltage regulator IC manufactured by Texas Instruments, delivering a fixed 3V output at 100mA in a SOT-23-5 surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The device provides positive fixed output configuration with integrated enable control and comprehensive protection features including over-current, over-temperature, and short-circuit protection.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3V
Output Current	100mA
Input Voltage (Max)	16V
Dropout Voltage (Max)	0.37V @ 100mA
Quiescent Current	95 µA
PSRR	63dB (1kHz)
Operating Temperature Range	-40°C to 125°C
Package	SOT-23-5 (SC-74A)
Control Features	Enable
Protection Features	Over Current, Over Temperature, Short Circuit

Substitute Part Grouping Explanation

Substitution eligibility for the LP2981IM5X-3.0 is determined by the following critical parameters: fixed 3V output voltage, 100mA output current capability, SOT-23-5 package compatibility, 16V maximum input voltage rating, and operating temperature range of -40°C to 125°C. All substitute parts must maintain these electrical and mechanical specifications to ensure direct functional replacement without circuit redesign.

The substitute parts are grouped into two categories:

Texas Instruments LP2981 Series (Parametric Equivalents): Parts LP2981-30DBVR, LP2981-30DBVT, LP2981A-30DBVR, LP2981A-30DBVRG4, LP2981A-30DBVT, LP2981A-30DBVTG4, and LP2981AIM5-3.0/NOPB maintain identical electrical specifications and package configuration. Differences exist only in product status, packaging format (Cut Tape, Tape & Reel, or bulk), and RoHS compliance status.

Cross-Manufacturer Alternatives: The LD2981ABM30TR from STMicroelectronics provides full parametric equivalence with identical output current, voltage ratings, and package. The LD2980ABM30TR from STMicroelectronics is a reduced-current variant (50mA output) and is suitable only when lower current requirements are acceptable.

Parameter Comparison

Part Number	Manufacturer	Output Current	Dropout Voltage	Quiescent Current	Product Status	RoHS Status	Packaging
LP2981IM5X-3.0	Texas Instruments	100mA	0.37V @ 100mA	95 µA	Obsolete	Non-compliant	SOT-23-5
LP2981-30DBVR	Texas Instruments	100mA	0.37V @ 100mA	95 µA	Active	ROHS3 Compliant	SOT-23-5
LP2981-30DBVT	Texas Instruments	100mA	0.37V @ 100mA	95 µA	Active	ROHS3 Compliant	SOT-23-5
LP2981A-30DBVR	Texas Instruments	100mA	0.37V @ 100mA	95 µA	Active	ROHS3 Compliant	SOT-23-5
LP2981A-30DBVRG4	Texas Instruments	100mA	0.37V @ 100mA	95 µA	Discontinued at DiGi Electronics	ROHS3 Compliant	SOT-23-5
LP2981A-30DBVT	Texas Instruments	100mA	0.37V @ 100mA	95 µA	Obsolete	ROHS3 Compliant	SOT-23-5
LP2981A-30DBVTG4	Texas Instruments	100mA	0.37V @ 100mA	95 µA	Discontinued at DiGi Electronics	ROHS3 Compliant	SOT-23-5
LP2981AIM5-3.0/NOPB	Texas Instruments	100mA	0.37V @ 100mA	95 µA	Obsolete	ROHS3 Compliant	SOT-23-5
LP2981IM5X-3.0/NOPB	National Semiconductor	100mA	0.37V @ 100mA	95 µA	Active	Not specified	SOT-23-5
LD2981ABM30TR	STMicroelectronics	100mA	0.375V @ 100mA	150 µA	Active	ROHS3 Compliant	SOT-23-5
LD2980ABM30TR	STMicroelectronics	50mA	0.225V @ 50mA	150 µA	Active	ROHS3 Compliant	SOT-23-5

Engineering Selection Recommendations

Primary Substitutes (Direct Replacement): LP2981-30DBVR and LP2981-30DBVT are the preferred substitutes. Both are active products from Texas Instruments with ROHS3 compliance, identical electrical specifications, and full SOT-23-5 package compatibility. LP2981-30DBVR is available in Cut Tape & Digi-Reel packaging with 5,000,300 pieces in stock. LP2981-30DBVT is available in Tape & Reel format with 17,603 pieces in stock. Selection between these two depends on packaging and procurement requirements.

Secondary Substitutes (Active Status): LP2981A-30DBVR and LP2981IM5X-3.0/NOPB maintain active product status with identical electrical performance. LP2981A-30DBVR offers ROHS3 compliance and 4,267 pieces in stock. LP2981IM5X-3.0/NOPB from National Semiconductor provides active availability with 1,557 pieces in stock.

Cross-Manufacturer Alternative: LD2981ABM30TR from STMicroelectronics is a full parametric equivalent with 30,420 pieces in stock and active product status. The quiescent current specification differs slightly (150 µA versus 95 µA), and dropout voltage is marginally higher (0.375V versus 0.37V), but these differences remain within acceptable engineering tolerances for most applications. ROHS3 compliance is confirmed.

Reduced-Current Alternative: LD2980ABM30TR from STMicroelectronics is suitable only for applications where 50mA output current is sufficient. This part is not recommended as a direct substitute for 100mA applications.

Obsolete Parts to Avoid: LP2981A-30DBVT and LP2981AIM5-3.0/NOPB are classified as obsolete and should not be selected for new designs despite available inventory.

Frequently Asked Questions (FAQ)

Q: Can LP2981-30DBVR directly replace LP2981IM5X-3.0?

A: Yes. Both parts deliver 3V fixed output at 100mA with identical dropout voltage (0.37V @ 100mA), quiescent current (95 µA), and SOT-23-5 package configuration. LP2981-30DBVR is an active product with ROHS3 compliance, making it the preferred direct replacement.

Q: What is the difference between LP2981-30DBVR and LP2981-30DBVT?

A: Both parts are electrically identical. The difference is packaging format: LP2981-30DBVR is supplied in Cut Tape & Digi-Reel format, while LP2981-30DBVT is supplied in Tape & Reel format. Selection depends on procurement and assembly line requirements.

Q: Is LD2981ABM30TR from STMicroelectronics a suitable substitute?

A: Yes, with minor parameter variations. The LD2981ABM30TR maintains 100mA output current and 3V fixed output voltage in SOT-23-5 package. Quiescent current is higher (150 µA versus 95 µA) and dropout voltage is marginally higher (0.375V versus 0.37V). These differences are typically acceptable for most applications. Confirm compatibility with your specific circuit requirements.

Q: Why is LD2980ABM30TR not recommended as a substitute?

A: The LD2980ABM30TR is rated for 50mA maximum output current, compared to the 100mA requirement of the LP2981IM5X-3.0. This part is suitable only for applications with reduced current demands and should not be used as a direct substitute for 100mA designs.

Q: Should I use obsolete parts like LP2981A-30DBVT for new designs?

A: No. Although inventory is available, obsolete parts should not be selected for new designs. Active alternatives such as LP2981-30DBVR or LP2981-30DBVT provide superior long-term supply assurance and regulatory compliance.

Q: Are all substitute parts RoHS compliant?

A: Most active substitutes are ROHS3 compliant, including LP2981-30DBVR, LP2981-30DBVT, LP2981A-30DBVR, and LD2981ABM30TR. The original LP2981IM5X-3.0 is RoHS non-compliant. Verify RoHS compliance requirements for your application before final part selection.

Q: What is the significance of the "G4" suffix in part numbers like LP2981A-30DBVRG4?

A: The G4 suffix indicates a specific manufacturing date code or qualification level. Parts with G4 designation are discontinued at DiGi Electronics and should not be selected for new designs despite available inventory.

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