LP2950ACZ-3.3RA Equivalent & Substitute Parts

Part Overview

The LP2950ACZ-3.3RA is a linear voltage regulator IC from onsemi, delivering a fixed 3.3V output at 100mA in a TO-92-3 package. This part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements. Direct replacements and parametric equivalents are available from onsemi, STMicroelectronics, and Texas Instruments, all meeting the same electrical and mechanical specifications.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3.3V
Output Current	100mA
Input Voltage (Max)	30V
Voltage Dropout (Max)	0.45V @ 100mA
Quiescent Current (Iq)	120 µA
Operating Temperature Range	-40°C ~ 125°C
Package / Case	TO-226-3, TO-92-3 Long Body (Formed Leads)
Mounting Type	Through Hole
Protection Features	Over Current, Over Temperature

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Direct Manufacturer Equivalents (onsemi LP2950 series): Parts with identical electrical specifications, output voltage, current rating, input voltage range, dropout voltage, quiescent current, operating temperature range, and TO-92-3 package configuration. These include LP2950ACZ-3.3RAG and LP2950CZ-3.3RAG, differing only in product status (Active vs. Obsolete) and packaging format (Cut Tape vs. Bulk).

Parametric Equivalents (Cross-manufacturer): Parts meeting all critical electrical parameters—3.3V fixed output, 100mA current capacity, 30V maximum input, TO-92-3 package, and -40°C to 125°C operating range—regardless of manufacturer. STMicroelectronics L78L33 series and Texas Instruments LP2950-33LPRE3 qualify under this category.

Key substitution parameters: Output voltage (3.3V), output current (100mA), input voltage rating (30V), package type (TO-92-3), and operating temperature range (-40°C to 125°C).

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage	Iq	Operating Temp	Package	Product Status	RoHS Status
LP2950ACZ-3.3RA	onsemi	3.3V	100mA	30V	0.45V @ 100mA	120 µA	-40°C ~ 125°C	TO-92-3	Obsolete	Non-compliant
LP2950ACZ-3.3RAG	onsemi	3.3V	100mA	30V	0.45V @ 100mA	120 µA	-40°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant
LP2950CZ-3.3RAG	onsemi	3.3V	100mA	30V	0.45V @ 100mA	120 µA	-40°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant
L78L33ABZ-AP	STMicroelectronics	3.3V	100mA	30V	Not specified	5.5 mA	-40°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant
L78L33ACZ	STMicroelectronics	3.3V	100mA	30V	Not specified	5.5 mA	0°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant
L78L33ACZ-AP	STMicroelectronics	3.3V	100mA	30V	Not specified	5.5 mA	0°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant
L78L33ACZTR	STMicroelectronics	3.3V	100mA	30V	Not specified	5.5 mA	0°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant
LP2950-33LPRE3	Texas Instruments	3.3V	100mA	30V	0.6V @ 100mA	120 µA	-40°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant
LP2950CZ-3.3/LFT3	Texas Instruments	3.3V	100mA	30V	0.6V @ 100mA	120 µA	-40°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: LP2950ACZ-3.3RAG (onsemi) is the direct successor to the obsolete LP2950ACZ-3.3RA. It maintains identical electrical specifications and package configuration while offering Active product status and ROHS3 compliance. This part is the preferred choice for direct replacement in existing designs.

Alternative from onsemi: LP2950CZ-3.3RAG provides the same electrical performance and compliance profile as LP2950ACZ-3.3RAG, with Active status and ROHS3 compliance.

Cross-Manufacturer Alternatives:

Texas Instruments LP2950-33LPRE3 and LP2950CZ-3.3/LFT3 are functionally equivalent, maintaining the same output voltage, current rating, input voltage range, and operating temperature. Both are Active products with ROHS3 compliance. Dropout voltage specification differs slightly (0.6V vs. 0.45V), which may be relevant in low-input-voltage applications.

STMicroelectronics L78L33 series (L78L33ACZ, L78L33ACZ-AP, L78L33ABZ-AP, L78L33ACZTR) meets all critical electrical and mechanical parameters. These parts are Active and ROHS3 compliant. Quiescent current is lower (5.5 mA vs. 120 µA), which may provide advantages in low-power applications. Operating temperature range for L78L33ACZ, L78L33ACZ-AP, and L78L33ACZTR is 0°C to 125°C, narrower than the original part's -40°C to 125°C range; L78L33ABZ-AP maintains the full -40°C to 125°C range.

All substitute parts are through-hole mounted in TO-92-3 packages and include over-current and over-temperature protection.

Frequently Asked Questions (FAQ)

Q: Can I use LP2950ACZ-3.3RAG as a direct replacement for LP2950ACZ-3.3RA?

A: Yes. LP2950ACZ-3.3RAG is electrically and mechanically identical to the obsolete LP2950ACZ-3.3RA, with the same 3.3V output, 100mA current capacity, 30V input rating, TO-92-3 package, and -40°C to 125°C operating range. The primary difference is product status (Active vs. Obsolete) and RoHS compliance (ROHS3 vs. non-compliant).

Q: What is the difference between onsemi and Texas Instruments LP2950 variants?

A: Both manufacturers' LP2950 series deliver 3.3V at 100mA with identical package and operating temperature specifications. The dropout voltage specification differs: onsemi specifies 0.45V @ 100mA, while Texas Instruments specifies 0.6V @ 100mA. This difference is relevant only in applications with tight input voltage margins.

Q: Why do STMicroelectronics L78L33 parts have lower quiescent current?

A: The L78L33 series is a different design from the LP2950, resulting in lower quiescent current (5.5 mA vs. 120 µA). Both designs meet the 100mA output current and 3.3V output voltage requirements. The lower quiescent current may benefit battery-powered or low-power applications.

Q: Does the operating temperature range matter for my application?

A: The original LP2950ACZ-3.3RA operates from -40°C to 125°C. Most STMicroelectronics L78L33 variants (L78L33ACZ, L78L33ACZ-AP, L78L33ACZTR) operate from 0°C to 125°C, which is narrower. If your application requires operation below 0°C, use L78L33ABZ-AP (which maintains -40°C to 125°C) or onsemi/Texas Instruments LP2950 variants.

Q: Are all substitute parts RoHS compliant?

A: All Active substitute parts listed are ROHS3 compliant. The original LP2950ACZ-3.3RA is RoHS non-compliant. If RoHS compliance is required for your application, select from the Active alternatives.

Q: Can I mix different manufacturers' parts in the same production run?

A: All substitute parts are mechanically and electrically compatible within the specified parameters. However, verify that your circuit design accommodates the dropout voltage and quiescent current specifications of the selected part, as these vary slightly between manufacturers.

Q: What packaging formats are available?

A: Substitute parts are available in Cut Tape (CT) and Bulk packaging formats. LP2950ACZ-3.3RAG and LP2950CZ-3.3RAG are available in Cut Tape. L78L33ACZ is available in Bulk. Select the packaging format that matches your procurement and assembly requirements.

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