MIC29310-3.3BU TR Equivalent & Substitute Parts

Part Overview

The MIC29310-3.3BU TR is a linear voltage regulator IC from Microchip Technology designed to deliver a fixed 3.3V output at 3A in a TO-263-3 surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The device provides positive fixed output regulation with integrated protection features including over-current, over-temperature, and reverse polarity protection, operating across a 0°C to 125°C temperature range.

Key Parameters

Parameter	Value
Manufacturer	Microchip Technology
Part Number	MIC29310-3.3BU TR
Category	Power Management (PMIC)
Output Voltage	3.3V Fixed
Output Current	3A
Input Voltage (Max)	16V
Dropout Voltage	1V @ 3A
Package Type	TO-263-3 (D2PAK)
Operating Temperature	0°C ~ 125°C
Product Status	Obsolete
RoHS Status	RoHS Non-Compliant

Substitute Part Grouping Explanation

Substitute parts for the MIC29310-3.3BU TR are selected based on the following critical parameters:

Output voltage: 3.3V fixed
Output current capability: 3A or greater
Input voltage maximum: 16V or greater
Package type: TO-263-3 compatible (D2PAK with 3 leads plus tab)
Output configuration: Positive fixed
Protection features: Over-current and over-temperature minimum

Substitutes are grouped into two categories:

Direct Parametric Equivalents (3A Output): Parts maintaining the full 3A output current specification with identical electrical performance.

Functional Alternatives (Reduced Current): Parts with 1A output current that provide functional regulation at lower current levels, suitable for applications not requiring the full 3A capacity.

Parameter Comparison

Parameter	MIC29310-3.3BU TR	MIC29310-3.3WU-TR	LT1587CM-3.3#PBF	LT1587CM-3.3#TRPBF	SPX29300T-L-3-3/TR	SPX3940AT-L-3-3/TR	SPX3940T-L-3-3/TR
Manufacturer	Microchip	Microchip	Analog Devices	Analog Devices	MaxLinear	MaxLinear	MaxLinear
Output Voltage	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V
Output Current	3A	3A	3A	3A	3A	1A	1A
Input Voltage (Max)	16V	16V	7V	7V	16V	16V	16V
Dropout Voltage @ Rated Current	1V @ 3A	1V @ 3A	1.3V @ 3A	1.3V @ 3A	0.8V @ 3A	0.55V @ 1A	0.55V @ 1A
Package Type	TO-263-3	TO-263-3	DDPAK-3	DDPAK-3	TO-263-3	TO-263-3	TO-263-3
Operating Temperature	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	Non-Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	RoHS Compliant	RoHS Compliant	ROHS3 Compliant
MSL Rating	3 (168 Hours)	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)	3 (168 Hours)	3 (168 Hours)	3 (168 Hours)

Engineering Selection Recommendations

For Direct 3A Replacement (Preferred):

MIC29310-3.3WU-TR is the primary substitute, offering identical electrical specifications with active product status and ROHS3 compliance. This part maintains the same 3A output current, 1V dropout voltage, and 16V maximum input voltage as the original MIC29310-3.3BU TR.

SPX29300T-L-3-3/TR provides an alternative 3A solution with improved dropout voltage (0.8V @ 3A) and extended operating temperature range (-40°C to 125°C). This part is RoHS compliant and actively produced.

LT1587CM-3.3#PBF and LT1587CM-3.3#TRPBF from Analog Devices maintain 3A output capability with ROHS3 compliance and superior moisture sensitivity rating (MSL 1). However, these parts have a reduced maximum input voltage of 7V and higher dropout voltage (1.3V @ 3A) compared to the original specification.

For Reduced Current Applications (1A):

SPX3940AT-L-3-3/TR and SPX3940T-L-3-3/TR are suitable only for applications requiring 1A or less output current. These parts offer superior dropout voltage (0.55V @ 1A), extended temperature range (-40°C to 125°C), and comprehensive protection features. Both are RoHS compliant and actively produced.

Compliance Considerations:

All active substitute parts listed are RoHS compliant, addressing the non-compliance status of the obsolete MIC29310-3.3BU TR. Selection should prioritize parts with ROHS3 certification for maximum regulatory alignment.

Frequently Asked Questions (FAQ)

Q: Can MIC29310-3.3WU-TR be used as a direct replacement for MIC29310-3.3BU TR?

A: Yes. MIC29310-3.3WU-TR is a parametric equivalent with identical output voltage (3.3V), output current (3A), input voltage rating (16V), and dropout voltage (1V @ 3A). The primary difference is product status (active vs. obsolete) and RoHS compliance (ROHS3 vs. non-compliant). Pinout and package type (TO-263-3) are identical.

Q: What is the difference between the Analog Devices LT1587 variants?

A: LT1587CM-3.3#PBF is supplied in tube packaging, while LT1587CM-3.3#TRPBF is supplied in cut tape and Digi-Reel format. Both parts are electrically identical with 3A output, 3.3V fixed output, and ROHS3 compliance. The packaging difference affects handling and automated assembly compatibility.

Q: Why do SPX3940 parts have lower output current than the original?

A: SPX3940AT-L-3-3/TR and SPX3940T-L-3-3/TR are rated for 1A output current, compared to the 3A specification of MIC29310-3.3BU TR. These parts are functional alternatives suitable only for applications with lower current requirements. For full 3A capability, use MIC29310-3.3WU-TR or SPX29300T-L-3-3/TR.

Q: What is the significance of the input voltage difference in LT1587 parts?

A: LT1587CM-3.3#PBF and LT1587CM-3.3#TRPBF have a maximum input voltage of 7V, compared to 16V for the original MIC29310-3.3BU TR. This limits their use to applications with lower input voltage supplies. Verify input voltage requirements before selecting these parts.

Q: Are all substitute parts pin-compatible with the original?

A: All listed substitutes use TO-263-3 or DDPAK-3 packaging (mechanically and electrically equivalent D2PAK formats with 3 leads plus tab). Pin assignments are identical across all parts listed. PCB layout modifications are not required.

Q: Which substitute offers the best dropout voltage performance?

A: SPX3940AT-L-3-3/TR and SPX3940T-L-3-3/TR offer the lowest dropout voltage at 0.55V @ 1A. For 3A applications, SPX29300T-L-3-3/TR provides the best dropout voltage at 0.8V @ 3A. The original MIC29310-3.3BU TR and its direct equivalent MIC29310-3.3WU-TR have 1V dropout voltage @ 3A.

Q: What is the moisture sensitivity level (MSL) and why does it matter?

A: MSL indicates the maximum time a component can be stored in ambient conditions before requiring baking before reflow soldering. LT1587 parts have MSL 1 (unlimited storage), while other parts have MSL 3 (168 hours maximum). For long-term inventory or delayed assembly, LT1587 parts offer advantages in handling flexibility.

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