SPX2954S-L-3-3 Equivalent & Substitute Parts

Part Overview

The SPX2954S-L-3-3 is a linear voltage regulator IC manufactured by MaxLinear, Inc., designed to deliver a fixed 3.3V output at 250mA with a maximum dropout voltage of 0.5V. This 8-SOIC surface mount device includes integrated over-current and over-temperature protection, along with enable and power-on-reset control features. The part is RoHS compliant and rated for operation across -40°C to 125°C.

The SPX2954S-L-3-3 is currently discontinued at DiGi Electronics. Equivalent substitute parts are available from active manufacturers including onsemi and Texas Instruments, offering comparable or enhanced electrical performance within the same package footprint.

Key Parameters

Parameter	SPX2954S-L-3-3
Manufacturer	MaxLinear, Inc.
Output Voltage (Fixed)	3.3V
Output Current	250mA
Input Voltage (Max)	30V
Dropout Voltage (Max)	0.5V @ 250mA
Quiescent Current	170 µA
Package	8-SOIC (0.154", 3.90mm Width)
Operating Temperature	-40°C ~ 125°C
Protection Features	Over Current, Over Temperature
Control Features	Enable, Power On Reset
RoHS Status	RoHS Compliant
Product Status	Discontinued at DiGi Electronics

Substitute Part Grouping Explanation

Substitution of the SPX2954S-L-3-3 is determined by the following critical parameters:

Electrical Compatibility Requirements:

Fixed output voltage of 3.3V
Input voltage tolerance up to 30V maximum
Operating temperature range -40°C to 125°C
Package type: 8-SOIC surface mount
Over-current and over-temperature protection

Output Current Consideration: The SPX2954S-L-3-3 delivers 250mA output current. All identified substitute parts deliver 100mA maximum output current. Substitution is valid only for applications requiring 100mA or less. Applications requiring the full 250mA output current cannot use these substitutes.

Substitute Parts Identified:

onsemi LP2951 Series (Fixed Output): LP2951ACD-3.3R2G, LP2951CD-3.3R2G, NCV2951ACD3.3R2G
- Fixed 3.3V output, 100mA maximum
- Dropout voltage 0.45V @ 100mA
- Active product status
- NCV2951ACD3.3R2G includes automotive qualification (AEC-Q100)
Texas Instruments LP2951 Series (Adjustable/Fixed): LP2951ACM-3.3/NOPB, LP2951ACMX-3.3/NOPB, LP2951CM-3.3/NOPB, LP2951CMX-3.3/NOPB
- Adjustable output with fixed 3.3V configuration, 100mA maximum
- Dropout voltage 0.6V @ 100mA
- Enable control feature
- Active product status

Parameter Comparison

Parameter	SPX2954S-L-3-3	LP2951ACD-3.3R2G	LP2951ACM-3.3/NOPB	LP2951ACMX-3.3/NOPB	LP2951CD-3.3R2G	LP2951CM-3.3/NOPB	LP2951CMX-3.3/NOPB	NCV2951ACD3.3R2G
Manufacturer	MaxLinear	onsemi	Texas Instruments	Texas Instruments	onsemi	Texas Instruments	Texas Instruments	onsemi
Output Voltage	3.3V (Fixed)	3.3V (Fixed)	3.3V (Adjustable/Fixed)	3.3V (Adjustable/Fixed)	3.3V (Fixed)	3.3V (Adjustable/Fixed)	3.3V (Adjustable/Fixed)	3.3V (Fixed)
Output Current	250mA	100mA	100mA	100mA	100mA	100mA	100mA	100mA
Input Voltage (Max)	30V	30V	30V	30V	30V	30V	30V	30V
Dropout Voltage (Max)	0.5V @ 250mA	0.45V @ 100mA	0.6V @ 100mA	0.6V @ 100mA	0.45V @ 100mA	0.6V @ 100mA	0.6V @ 100mA	0.45V @ 100mA
Quiescent Current	170 µA	120 µA	120 µA	120 µA	120 µA	120 µA	120 µA	Not specified
Operating Temperature	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C (TJ)	-40°C ~ 125°C (TJ)	-40°C ~ 125°C	-40°C ~ 125°C (TJ)	-40°C ~ 125°C (TJ)	-40°C ~ 125°C
Package	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Protection Features	Over Current, Over Temperature	Over Current, Over Temperature	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature
Control Features	Enable, Power On Reset	None	Enable	Enable	None	Enable	Enable	None
Product Status	Discontinued	Active	Active	Active	Active	Active	Active	Active
RoHS Status	RoHS Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Automotive Grade	Not specified	Not specified	Not specified	Not specified	Not specified	Not specified	Not specified	AEC-Q100

Engineering Selection Recommendations

Primary Substitutes for General Applications (100mA or Less):

LP2951ACMX-3.3/NOPB and LP2951CMX-3.3/NOPB from Texas Instruments are the preferred substitutes. Both are active products with high inventory availability (163,395 and 30,100 units respectively), ROHS3 compliance, and enable control functionality. The adjustable output configuration provides design flexibility while maintaining fixed 3.3V operation.

Alternative Fixed-Output Substitutes:

LP2951ACD-3.3R2G and LP2951CD-3.3R2G from onsemi deliver fixed 3.3V output with lower dropout voltage (0.45V @ 100mA) compared to the Texas Instruments adjustable variants. These are suitable for applications where fixed output is preferred and enable control is not required.

Automotive Applications:

NCV2951ACD3.3R2G from onsemi is the only substitute with automotive qualification (AEC-Q100). This part is required for automotive-grade designs and meets the same electrical specifications as other onsemi LP2951 fixed-output variants.

Current Limitation:

All substitute parts are rated for 100mA maximum output current. The original SPX2954S-L-3-3 delivers 250mA. Direct substitution is valid only for applications drawing 100mA or less. Applications requiring higher current must source alternative regulators with higher current ratings.

Frequently Asked Questions (FAQ)

Q: Can I use a 100mA substitute in place of the 250mA SPX2954S-L-3-3?

A: Only if your application draws 100mA or less. The substitute parts are rated for a maximum of 100mA output current. Exceeding this rating will cause the regulator to enter current-limit protection or fail. Verify your actual load current before substitution.

Q: What is the difference between fixed and adjustable output LP2951 variants?

A: Fixed-output variants (LP2951ACD-3.3R2G, LP2951CD-3.3R2G, NCV2951ACD3.3R2G) deliver a preset 3.3V output. Adjustable variants (LP2951ACM-3.3/NOPB, LP2951ACMX-3.3/NOPB, LP2951CM-3.3/NOPB, LP2951CMX-3.3/NOPB) can be configured for different output voltages but are factory-set to 3.3V in the specified part numbers. Both are electrically equivalent for 3.3V applications.

Q: Are all substitutes pin-compatible with the SPX2954S-L-3-3?

A: All substitute parts use the 8-SOIC package with identical 0.154" width and 3.90mm body dimensions. Pin compatibility must be verified against the specific datasheet, as control feature differences (Enable, Power On Reset) may affect pin assignments.

Q: Which substitute has the best dropout voltage performance?

A: LP2951ACD-3.3R2G, LP2951CD-3.3R2G, and NCV2951ACD3.3R2G from onsemi deliver 0.45V dropout voltage at 100mA, compared to 0.6V for Texas Instruments adjustable variants. The onsemi fixed-output parts are superior for low-headroom applications.

Q: Is the NCV2951ACD3.3R2G suitable for non-automotive applications?

A: Yes. The NCV2951ACD3.3R2G meets AEC-Q100 automotive qualification but is not restricted to automotive use. It can be used in any application requiring the same electrical specifications. Automotive-qualified parts typically offer enhanced reliability screening.

Q: What packaging options are available for substitutes?

A: Substitute parts are available in Tube, Cut Tape (CT) & Digi-Reel, and Tape & Reel (TR) packaging. Select packaging based on your procurement and assembly requirements. All packaging options contain the same die and electrical performance.

Q: Do all substitutes include the same protection features as the original?

A: All substitutes include over-current and over-temperature protection. Texas Instruments LP2951 adjustable variants add short-circuit protection. The original SPX2954S-L-3-3 includes power-on-reset functionality, which is not present in any substitute. Verify that your design does not depend on power-on-reset behavior.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message