LP2951CS-L-3-3 Equivalent & Substitute Parts

Part Overview

The LP2951CS-L-3-3 is a linear voltage regulator IC providing positive fixed 3.3V output at 100mA in an 8-SOIC surface mount package. Manufactured by MaxLinear, Inc., this component is discontinued at DiGi Electronics. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications requiring 3.3V regulation with 100mA output capacity.

Key Parameters

Parameter	Value
Manufacturer Part Number	LP2951CS-L-3-3
Manufacturer	MaxLinear, Inc.
Category	Power Management (PMIC)
Description	IC REG LINEAR 3.3V 100MA 8SOIC
Output Configuration	Positive
Output Type	Fixed
Voltage - Output (Fixed)	3.3V
Current - Output	100mA
Voltage - Input (Max)	30V
Voltage Dropout (Max)	0.45V @ 100mA
Current - Quiescent (Iq)	170 µA
Operating Temperature	-40°C ~ 125°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Protection Features	Over Current, Over Temperature
RoHS Status	RoHS Compliant
Product Status	Discontinued at DiGi Electronics

Substitute Part Grouping Explanation

Substitution for the LP2951CS-L-3-3 is determined by the following critical parameters:

Output Voltage: Fixed 3.3V output
Output Current: 100mA minimum capacity
Package: 8-SOIC form factor with 0.154" (3.90mm) width
Input Voltage Range: Maximum 30V input tolerance
Voltage Dropout: Maximum 0.45V @ 100mA
Operating Temperature Range: -40°C to 125°C
Surface Mount Configuration: Direct PCB compatibility
Protection Features: Over current and over temperature protection

Substitute parts are grouped into two categories:

Category 1: Fixed 3.3V Output Regulators — Parts with fixed 3.3V output matching the original specification exactly. These include LP2951CM-3.3/NOPB, LP2951CMX-3.3/NOPB, and LP2951ACD-3.3R2G from Texas Instruments and onsemi.

Category 2: Adjustable Output Regulators Configured for 3.3V — Parts with adjustable output capability that can be configured to 3.3V through external resistor networks. These include LP2951-30D, LP2951-30DR, LP2951-33D, and LP2951-33DR from Texas Instruments, and LP2951ACDR2G from onsemi.

All substitute parts maintain identical package geometry, input voltage tolerance, and operating temperature range, ensuring direct PCB compatibility and thermal performance equivalence.

Parameter Comparison

Parameter	LP2951CS-L-3-3 (Main)	LP2951CM-3.3/NOPB	LP2951CMX-3.3/NOPB	LP2951-33D	LP2951-33DR	LP2951ACD-3.3R2G
Manufacturer	MaxLinear, Inc.	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	onsemi
Output Type	Fixed	Adjustable (Fixed)	Adjustable (Fixed)	Adjustable (Fixed)	Adjustable (Fixed)	Fixed
Voltage - Output (Fixed)	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V
Current - Output	100mA	100mA	100mA	100mA	100mA	100mA
Voltage - Input (Max)	30V	30V	30V	30V	30V	30V
Voltage Dropout (Max)	0.45V @ 100mA	0.6V @ 100mA	0.6V @ 100mA	0.6V @ 100mA	0.6V @ 100mA	0.45V @ 100mA
Current - Quiescent (Iq)	170 µA	120 µA	120 µA	120 µA	120 µA	120 µA
Operating Temperature	-40°C ~ 125°C	-40°C ~ 125°C (TJ)	-40°C ~ 125°C (TJ)	-40°C ~ 125°C (TJ)	-40°C ~ 125°C (TJ)	-40°C ~ 125°C
Package / Case	8-SOIC (0.154", 3.90mm)	8-SOIC (0.154", 3.90mm)	8-SOIC (0.154", 3.90mm)	8-SOIC (0.154", 3.90mm)	8-SOIC (0.154", 3.90mm)	8-SOIC (0.154", 3.90mm)
Protection Features	Over Current, Over Temperature	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature
RoHS Status	RoHS Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Discontinued	Active	Active	Last Time Buy	Active	Active

Engineering Selection Recommendations

Primary Substitutes (Active Product Status)

LP2951CMX-3.3/NOPB and LP2951CM-3.3/NOPB from Texas Instruments are the preferred direct replacements. Both are in active production status with high inventory availability (30,100 and 26,145 units respectively). These fixed 3.3V output regulators require no external configuration and provide identical electrical performance to the original part. The LP2951CMX-3.3/NOPB is supplied in Cut Tape (CT) & Digi-Reel packaging, while LP2951CM-3.3/NOPB is supplied in Tube packaging.

LP2951ACD-3.3R2G from onsemi is an alternative active substitute with matching fixed 3.3V output and identical dropout voltage specification (0.45V @ 100mA). This part maintains full compatibility with the original design and is available in Cut Tape & Digi-Reel packaging with 2,616 units in stock.

Secondary Substitutes (Last Time Buy Status)

LP2951-33D and LP2951-33DR from Texas Instruments are adjustable output regulators configured for 3.3V output. These parts are in Last Time Buy and Active status respectively, with substantial inventory (65,300 and 65,400 units). The adjustable architecture requires external resistor configuration but provides identical 3.3V output performance. LP2951-33DR is supplied in Cut Tape & Digi-Reel packaging.

Compliance and Certification

All substitute parts maintain ROHS3 compliance and RoHS Compliant status. Texas Instruments parts include REACH Unaffected certification. All parts are classified under ECCN EAR99 and HTSUS 8542.39.0001, matching the original part's regulatory classification.

Frequently Asked Questions (FAQ)

Q: Can LP2951-33D and LP2951-33DR be used as direct drop-in replacements?

A: Yes, these adjustable output regulators can be configured for 3.3V output through external resistor networks. They maintain identical package geometry, input voltage tolerance, and operating temperature range. However, they require external component configuration, whereas the fixed output variants (LP2951CM-3.3/NOPB, LP2951CMX-3.3/NOPB) require no additional components.

Q: What is the difference between LP2951CM-3.3/NOPB and LP2951CMX-3.3/NOPB?

A: Both parts are functionally identical fixed 3.3V output regulators from Texas Instruments. The primary difference is packaging: LP2951CM-3.3/NOPB is supplied in Tube packaging, while LP2951CMX-3.3/NOPB is supplied in Cut Tape (CT) & Digi-Reel packaging. Select based on your assembly process requirements.

Q: Are there any performance differences between the MaxLinear original and Texas Instruments substitutes?

A: The Texas Instruments substitutes feature lower quiescent current (120 µA vs. 170 µA) and enhanced protection features including short circuit protection. Voltage dropout is slightly higher at 0.6V @ 100mA compared to the original 0.45V @ 100mA. These differences are within acceptable operating margins for most 3.3V regulation applications.

Q: Is the onsemi LP2951ACD-3.3R2G equivalent to the MaxLinear original?

A: Yes, the onsemi part matches the original specification exactly, including the 0.45V @ 100mA dropout voltage and 100 µA quiescent current specification. It is a direct functional equivalent with identical package geometry and electrical performance.

Q: What packaging options are available for 3.3V fixed output substitutes?

A: LP2951CM-3.3/NOPB is available in Tube packaging. LP2951CMX-3.3/NOPB and LP2951ACD-3.3R2G are available in Cut Tape (CT) & Digi-Reel packaging. Select based on your manufacturing process and volume requirements.

Q: Can I use parts with different output voltages (5V variants) in my design?

A: No. The LP2951-50D and LP2951-50DR are configured for 5V output and are not suitable for applications requiring 3.3V regulation. Use only parts specified for 3.3V output or adjustable variants configured for 3.3V.

Q: What is the inventory status for each substitute?

A: LP2951CMX-3.3/NOPB has the highest availability (30,100 units). LP2951CM-3.3/NOPB has 26,145 units. LP2951-33DR has 65,400 units. LP2951ACD-3.3R2G has 2,616 units. Verify current availability with your supplier before design finalization.

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