MIC5239-3.3BS TR Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The MIC5239-3.3BS TR is a linear voltage regulator IC from Microchip Technology designed to deliver a fixed 3.3V output at 500mA in a surface-mount SOT-223-3 package. This device is classified as obsolete, making equivalent and substitute parts necessary for new designs and production continuity. The MIC5239-3.3BS TR provides positive fixed output regulation with integrated protection features including over-current, over-temperature, over-voltage, and reverse polarity protection. Its 30V maximum input voltage and 0.35V typical dropout at 500mA make it suitable for general-purpose 3.3V power supply applications.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3.3V
Output Current	500mA
Input Voltage (Max)	30V
Dropout Voltage (Typ)	0.35V @ 500mA
Quiescent Current	45 µA
Operating Temperature Range	-40°C to 125°C
Package	SOT-223-3
Protection Features	Over Current, Over Temperature, Over Voltage, Reverse Polarity
Control Features	Enable

Substitute Part Grouping Explanation

Substitute parts for the MIC5239-3.3BS TR are grouped based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

Fixed output voltage of 3.3V
Output current capability of 500mA or greater
Surface-mount SOT-223 package (SOT-223-3 or SOT-223-4)
Operating temperature range of -40°C to 125°C or compatible subset
Positive fixed output configuration

Secondary Compatibility Factors:

Input voltage rating (minimum 26V to 30V acceptable)
Dropout voltage performance
Protection feature set (over-current, over-temperature minimum)
RoHS compliance status for new designs

Substitutes are classified into two categories: parametric equivalents (matching all primary criteria) and manufacturer-recommended alternatives (meeting functional requirements with acceptable trade-offs in secondary parameters).

Parameter Comparison

Parameter	MIC5239-3.3BS TR	MIC5239-3.3YS-TR	MCP1825ST-3302E/DB	LM2937IMP-3.3/NOPB	LM2937IMPX-3.3/NOPB	SPX2945M3-L-3-3/TR	SPX2954M3-L-3-3/TR
Manufacturer	Microchip	Microchip	Microchip	Texas Instruments	Texas Instruments	MaxLinear	MaxLinear
Output Voltage	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V
Output Current	500mA	500mA	500mA	500mA	500mA	400mA	250mA
Input Voltage (Max)	30V	30V	6V	26V	26V	26V	30V
Dropout Voltage (Typ)	0.35V @ 500mA	0.35V @ 500mA	0.35V @ 500mA	1V @ 500mA	1V @ 500mA	0.7V @ 400mA	0.5V @ 250mA
Quiescent Current	45 µA	45 µA	220 µA	10 mA	10 mA	300 µA	170 µA
Operating Temperature	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 85°C	-40°C to 85°C	-40°C to 85°C	-40°C to 125°C
Package	SOT-223-3	SOT-223-3	SOT-223-3	SOT-223-4	SOT-223-4	SOT-223-3	SOT-223-3
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	RoHS Compliant
Moisture Sensitivity (MSL)	3 (168 Hours)	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

Parametric Equivalent (Recommended Primary Substitute): MIC5239-3.3YS-TR is the direct parametric equivalent to the MIC5239-3.3BS TR. It maintains identical electrical specifications including 500mA output current, 30V maximum input voltage, 0.35V typical dropout, and 45 µA quiescent current. The primary advantage is active product status with ROHS3 compliance and improved moisture sensitivity rating (MSL 3). This part is suitable for direct replacement in existing designs without circuit modifications.

Manufacturer-Recommended Alternatives:

MCP1825ST-3302E/DB (Microchip) provides 500mA output current and 3.3V fixed output with ROHS3 compliance and superior moisture sensitivity (MSL 1). The trade-off is reduced maximum input voltage (6V versus 30V), making this suitable only for applications with input voltage limited to 6V or below.

LM2937IMP-3.3/NOPB and LM2937IMPX-3.3/NOPB (Texas Instruments) deliver 500mA output current with active status and ROHS3 compliance. These parts feature SOT-223-4 packaging and operate to -40°C to 85°C. The higher dropout voltage (1V @ 500mA) and lower quiescent current (10 mA) require circuit evaluation for thermal and efficiency impact.

SPX2945M3-L-3-3/TR (MaxLinear) provides 400mA output current with 26V maximum input voltage and 0.7V dropout. This part is suitable for applications requiring less than 400mA output current.

SPX2954M3-L-3-3/TR (MaxLinear) delivers 250mA output current with 30V maximum input voltage and extended temperature range to 125°C. This part is suitable for applications requiring 250mA or less output current.

Compliance Considerations: All substitute parts except MIC5239-3.3BS TR are ROHS3 compliant, making them suitable for new designs subject to RoHS regulations. The MCP1825ST-3302E/DB, LM2937 variants, and SPX2945M3-L-3-3/TR feature MSL 1 (unlimited moisture sensitivity), providing superior handling and storage flexibility compared to the original part's MSL 3 rating.

Frequently Asked Questions (FAQ)

Q: Can MIC5239-3.3YS-TR be used as a direct drop-in replacement for MIC5239-3.3BS TR?

A: Yes. MIC5239-3.3YS-TR is a parametric equivalent with identical electrical specifications. The primary differences are product status (active versus obsolete) and packaging format (Cut Tape & Digi-Reel versus Tape & Reel). No circuit modifications are required.

Q: What is the key limitation of MCP1825ST-3302E/DB as a substitute?

A: The MCP1825ST-3302E/DB has a maximum input voltage rating of 6V, compared to 30V for the MIC5239-3.3BS TR. This part is suitable only for applications where the input voltage does not exceed 6V. Exceeding this rating will damage the device.

Q: Why do LM2937IMP-3.3/NOPB and LM2937IMPX-3.3/NOPB have different part numbers?

A: Both parts are functionally identical with the same electrical specifications. The difference is in the manufacturing process or packaging format. Both are suitable substitutes with equivalent performance.

Q: Can SPX2954M3-L-3-3/TR replace the MIC5239-3.3BS TR in all applications?

A: SPX2954M3-L-3-3/TR has a maximum output current of 250mA, compared to 500mA for the original part. This substitute is suitable only for applications requiring 250mA or less output current. Applications requiring higher current will experience voltage regulation failure.

Q: What is the significance of the SOT-223-4 package used by LM2937 variants?

A: The SOT-223-4 package has four pins instead of three (SOT-223-3). While both packages are surface-mount and have similar physical dimensions, the PCB footprint differs. Verify that your PCB layout accommodates the four-pin configuration before selecting this substitute.

Q: Are all substitute parts RoHS compliant?

A: All substitute parts listed are RoHS compliant (ROHS3 or RoHS). The original MIC5239-3.3BS TR is RoHS non-compliant. For new designs subject to RoHS regulations, any of the listed substitutes are acceptable from a compliance perspective.

Q: Which substitute has the best moisture sensitivity rating?

A: MCP1825ST-3302E/DB, LM2937IMP-3.3/NOPB, LM2937IMPX-3.3/NOPB, and SPX2945M3-L-3-3/TR all have MSL 1 (unlimited moisture sensitivity), providing superior handling and storage flexibility compared to the original part's MSL 3 rating.

Q: What is the operating temperature range limitation for LM2937 variants?

A: LM2937IMP-3.3/NOPB and LM2937IMPX-3.3/NOPB operate from -40°C to 85°C, compared to -40°C to 125°C for the original part. These substitutes are not suitable for applications requiring operation above 85°C junction temperature.

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