LP2950ACZ-3.3 Equivalent & Substitute Parts

Part Overview

The LP2950ACZ-3.3 is a linear voltage regulator IC from onsemi, delivering a fixed positive 3.3V output at 100mA in a TO-92-3 package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The device provides over-current and over-temperature protection across an operating range of -40°C to 125°C, with a maximum input voltage of 30V and dropout voltage of 0.45V at 100mA.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3.3V
Output Current	100mA
Input Voltage (Max)	30V
Dropout Voltage (Max)	0.45V @ 100mA
Quiescent Current	120 µA
Operating Temperature	-40°C ~ 125°C
Package	TO-92-3 (TO-226-3)
Protection Features	Over Current, Over Temperature

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict alignment with the following electrical and mechanical parameters:

Output voltage: 3.3V fixed
Output current capability: 100mA minimum
Input voltage rating: 30V maximum
Package type: TO-92-3 (TO-226-3) through-hole configuration
Protection features: Over-current and over-temperature protection

Substitute parts are grouped into two categories:

Direct Manufacturer Equivalents (onsemi): Parts with identical electrical specifications and the same manufacturer, differing only in packaging format or product status designation.

Cross-Manufacturer Equivalents: Parts from STMicroelectronics and Texas Instruments meeting all electrical and mechanical requirements, with variations in quiescent current, dropout voltage, or protection feature sets.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage	Quiescent Current	Operating Temp	Package	Product Status	RoHS Status
LP2950ACZ-3.3	onsemi	3.3V	100mA	30V	0.45V @ 100mA	120 µA	-40°C ~ 125°C	TO-92-3	Obsolete	Non-compliant
LP2950ACZ-3.3G	onsemi	3.3V	100mA	30V	0.45V @ 100mA	120 µA	-40°C ~ 125°C	TO-92-3	Active	ROHS3 Compliant
LP2950CZ-3.3G	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
LP2950-33LPE3	Texas Instruments	3.3V	100mA	30V	0.6V @ 100mA	120 µA	-40°C ~ 125°C	TO-92-3	Last Time Buy	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
LP2950ACZ-3.3/NOPB	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-3.3G or LP2950CZ-3.3G (onsemi). These parts provide direct electrical equivalence to the obsolete LP2950ACZ-3.3 with active product status and ROHS3 compliance. Both maintain identical dropout voltage and quiescent current specifications.

Secondary Recommendation: LP2950-33LPRE3 (Texas Instruments). This part is actively produced with ROHS3 compliance and identical electrical performance. The 0.6V dropout voltage (versus 0.45V on the original) represents a minor increase acceptable in most 3.3V regulation applications.

Alternative Recommendation: L78L33ACZ or L78L33ACZ-AP (STMicroelectronics). These parts meet all electrical and mechanical requirements with active product status and ROHS3 compliance. The lower quiescent current (5.5 mA versus 120 µA) provides improved efficiency in low-power applications. Operating temperature range begins at 0°C rather than -40°C; verify suitability for your thermal environment.

Avoid: LP2950-33LPE3 (Texas Instruments) is designated Last Time Buy, indicating production discontinuation is planned.

Frequently Asked Questions (FAQ)

Q: Can I directly substitute LP2950ACZ-3.3 with LP2950ACZ-3.3G?

A: Yes. Both parts are onsemi products with identical electrical specifications (3.3V output, 100mA, 0.45V dropout, 120 µA quiescent current). The primary difference is product status: LP2950ACZ-3.3G is active and ROHS3 compliant, while the original is obsolete and non-compliant.

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

A: Both manufacturers produce LP2950-series regulators meeting the same 3.3V, 100mA specification. Texas Instruments variants specify 0.6V dropout voltage compared to onsemi's 0.45V. This 0.15V difference is typically negligible in 3.3V applications but should be verified if operating near minimum input voltage limits.

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

A: The L78L33 series uses different internal circuit topology, resulting in 5.5 mA quiescent current versus 120 µA for LP2950 variants. This makes L78L33 parts more efficient in battery-powered or low-power standby applications. All other electrical parameters remain equivalent.

Q: Are all substitute parts available in TO-92-3 package?

A: Yes. All listed substitute parts are specified for TO-92-3 (TO-226-3) through-hole mounting. Package compatibility is confirmed across all alternatives.

Q: Which substitute part has the best compliance status?

A: All active substitute parts carry ROHS3 compliance. LP2950ACZ-3.3G, LP2950CZ-3.3G, and all Texas Instruments and STMicroelectronics variants listed are ROHS3 compliant and REACH unaffected.

Q: Can I use L78L33ACZ if my application requires -40°C operation?

A: No. L78L33ACZ and L78L33ACZ-AP specify 0°C minimum operating temperature. For -40°C operation, use LP2950ACZ-3.3G, LP2950CZ-3.3G, or Texas Instruments LP2950 variants, all rated to -40°C.

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