LP2950CDT-3.3RK Equivalent & Substitute Parts

Part Overview

The LP2950CDT-3.3RK is a linear voltage regulator IC from onsemi, delivering a fixed 3.3V output at 100mA in a DPAK surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The regulator provides over-current and over-temperature protection suitable for low-power applications requiring stable 3.3V rails.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3.3V
Output Current	100mA
Input Voltage (Max)	30V
Dropout Voltage	0.45V @ 100mA
Quiescent Current	120 µA
Package	TO-252-3 DPAK
Operating Temperature	-40°C to 125°C
Protection Features	Over Current, Over Temperature

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following critical parameters:

Output Voltage: Must be fixed at 3.3V
Package Type: TO-252-3 DPAK (2 Leads + Tab, SC-63)
Mounting Type: Surface Mount
Operating Temperature Range: -40°C to 125°C
Protection Features: Over Current and Over Temperature protection required

Substitute parts are grouped into three categories:

Direct Manufacturer Equivalent: Identical electrical specifications and package, differing only in product status or packaging format
Parametric Equivalent: Identical core electrical specifications with active product status and RoHS3 compliance
Similar Functional Equivalent: Higher output current capability or improved specifications while maintaining 3.3V output, DPAK package, and temperature range

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Dropout Voltage	Quiescent Current	Product Status	RoHS Status
LP2950CDT-3.3RK	onsemi	100mA	30V	0.45V @ 100mA	120 µA	Obsolete	Non-compliant
LP2950CDT-3.3RKG	onsemi	100mA	30V	0.45V @ 100mA	120 µA	Active	RoHS3 Compliant
LP2950ACDT-3.3RG	onsemi	100mA	30V	0.45V @ 100mA	120 µA	Active	RoHS3 Compliant
LP2950CDT-3.3/NOPB	Texas Instruments	100mA	30V	0.6V @ 100mA	120 µA	Active	RoHS3 Compliant
LP2950CDTX-3.3/NOPB	Texas Instruments	100mA	30V	0.6V @ 100mA	120 µA	Active	RoHS3 Compliant
SM72238TDE-3.3/NOPB	Texas Instruments	100mA	30V	0.6V @ 100mA	140 µA	Active	RoHS3 Compliant
SM72238TDX-3.3/NOPB	National Semiconductor	100mA	30V	0.6V @ 100mA	140 µA	Active	RoHS3 Compliant
BA033CC0FP-E2	Rohm Semiconductor	1A	25V	Not specified	2.5 mA	Active	RoHS3 Compliant
LD29150DT33R	STMicroelectronics	1.5A	14V	0.7V @ 1.5A	180 µA	Active	RoHS3 Compliant
LF33ABDT-TR	STMicroelectronics	500mA	16V	0.7V @ 500mA	1 mA	Active	RoHS3 Compliant

Engineering Selection Recommendations

Direct Replacement (Recommended for Obsolete Part Transition):

LP2950CDT-3.3RKG and LP2950ACDT-3.3RG from onsemi provide identical electrical performance to the obsolete LP2950CDT-3.3RK while maintaining active product status and RoHS3 compliance. These parts require no circuit redesign and offer the shortest qualification path.

Cross-Manufacturer Equivalents (100mA Output Current):

LP2950CDT-3.3/NOPB and LP2950CDTX-3.3/NOPB from Texas Instruments deliver equivalent 100mA output current and 30V maximum input voltage. The dropout voltage specification is slightly higher at 0.6V versus 0.45V. SM72238TDE-3.3/NOPB and SM72238TDX-3.3/NOPB offer the same electrical performance with marginally higher quiescent current at 140 µA. All are RoHS3 compliant and actively supported.

Higher Current Alternatives (Design Flexibility):

BA033CC0FP-E2 (Rohm, 1A), LD29150DT33R (STMicroelectronics, 1.5A), and LF33ABDT-TR (STMicroelectronics, 500mA) provide increased output current capability while maintaining the 3.3V output and DPAK package. These are suitable when circuit requirements exceed 100mA or when design margin is needed. Input voltage maximums vary: BA033CC0FP-E2 at 25V, LD29150DT33R at 14V, and LF33ABDT-TR at 16V. All include RoHS3 compliance and active product status.

Frequently Asked Questions (FAQ)

Q: Can I use a higher current rated regulator as a direct substitute?

A: Yes. Higher current regulators (500mA, 1A, 1.5A) are functionally compatible in circuits designed for 100mA operation. The regulator will deliver the required 3.3V at lower current levels without performance degradation. Verify that the maximum input voltage specification meets your application requirements.

Q: What is the difference between LP2950CDT-3.3RKG and LP2950ACDT-3.3RG?

A: Both are onsemi equivalents with identical electrical specifications. The primary difference is packaging format: LP2950CDT-3.3RKG is supplied in Cut Tape and Digi-Reel format, while LP2950ACDT-3.3RG is supplied in Tape & Reel format. Select based on your procurement and assembly requirements.

Q: Are Texas Instruments LP2950 variants pin-compatible?

A: Yes. LP2950CDT-3.3/NOPB and LP2950CDTX-3.3/NOPB share identical pinouts and electrical performance. The primary difference is packaging: LP2950CDT-3.3/NOPB is supplied in Tube format, while LP2950CDTX-3.3/NOPB is supplied in Cut Tape & Digi-Reel format.

Q: Why do some substitutes have different input voltage maximums?

A: Input voltage ratings reflect the regulator's internal design and protection thresholds. LD29150DT33R (14V max) and LF33ABDT-TR (16V max) are optimized for lower input voltage applications. Verify your circuit's input voltage does not exceed the selected regulator's maximum specification.

Q: Is the DPAK package identical across all listed parts?

A: Yes. All parts use the TO-252-3 DPAK package (2 Leads + Tab, SC-63), ensuring mechanical and thermal compatibility. PCB footprints and thermal characteristics are equivalent.

Q: What compliance certifications apply to these parts?

A: All active substitute parts are RoHS3 compliant and REACH unaffected. The original LP2950CDT-3.3RK is RoHS non-compliant. For new designs, select RoHS3 compliant alternatives to meet current regulatory requirements.

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