MIC4576BU TR Equivalent & Substitute Parts

Part Overview

The MIC4576BU TR is a buck switching regulator IC from Microchip Technology, classified as a Power Management (PMIC) component. It functions as a step-down converter with positive adjustable output, delivering up to 3A output current across a wide input voltage range of 4V to 36V. The device operates at a fixed switching frequency of 200kHz and supports adjustable output voltage from 1.23V to 33V.

The MIC4576BU TR carries an obsolete product status. Identifying equivalent substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support ongoing production or maintenance requirements for systems utilizing this regulator.

Key Parameters

Parameter	Value
Function	Step-Down (Buck)
Output Configuration	Positive
Output Type	Adjustable
Number of Outputs	1
Voltage - Input (Min)	4V
Voltage - Input (Max)	36V
Voltage - Output (Min/Fixed)	1.23V
Voltage - Output (Max)	33V
Current - Output	3A
Frequency - Switching	200kHz
Synchronous Rectifier	No
Operating Temperature	-40°C ~ 85°C (TA)
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution of the MIC4576BU TR is determined by strict equivalence across the following critical parameters:

Function and topology (step-down buck converter)
Output configuration (positive adjustable)
Electrical specifications (input voltage range 4V–36V, output voltage range 1.23V–33V, 3A output current)
Switching frequency (200kHz)
Package type (TO-263-6, D2PAK with 5 leads plus tab)
Operating temperature range (-40°C ~ 85°C)

The MIC4576WU TR meets all these criteria and is identified as a direct substitute. Both parts share identical electrical performance characteristics, thermal specifications, and physical packaging. The primary distinction lies in product status and compliance certifications.

Parameter Comparison

Parameter	MIC4576BU TR	MIC4576WU TR
Manufacturer	Microchip Technology	Microchip Technology
Category	Power Management (PMIC)	Power Management (PMIC)
Function	Step-Down	Step-Down
Output Configuration	Positive	Positive
Output Type	Adjustable	Adjustable
Number of Outputs	1	1
Voltage - Input (Min)	4V	4V
Voltage - Input (Max)	36V	36V
Voltage - Output (Min/Fixed)	1.23V	1.23V
Voltage - Output (Max)	33V	33V
Current - Output	3A	3A
Frequency - Switching	200kHz	200kHz
Synchronous Rectifier	No	No
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)
Package / Case	TO-263-6, D2PAK (5 Leads + Tab)	TO-263-6, D2PAK (5 Leads + Tab)
Mounting Type	Surface Mount	Surface Mount
Product Status	Obsolete	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	3 (168 Hours)	3 (168 Hours)
REACH Status	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

The MIC4576WU TR is the direct substitute for the obsolete MIC4576BU TR. Both parts are manufactured by Microchip Technology and provide identical electrical and thermal performance within the same physical package.

Selection of the MIC4576WU TR is supported by the following factors:

Active product status ensures ongoing availability and manufacturer support
ROHS3 compliance meets current environmental and regulatory requirements, whereas the MIC4576BU TR is non-compliant
Identical electrical specifications guarantee functional equivalence in existing circuit designs
Matching package and pin configuration enable direct PCB-level substitution without layout modifications

For new designs or production transitions, the MIC4576WU TR is the appropriate choice. For legacy system maintenance where RoHS compliance is not a constraint, the MIC4576BU TR remains functionally equivalent if inventory is available.

Frequently Asked Questions (FAQ)

Q: Can the MIC4576WU TR be used as a direct replacement for the MIC4576BU TR on existing PCBs?

A: Yes. Both parts share identical pin configurations, package dimensions (TO-263-6, D2PAK), and electrical specifications. No PCB modifications are required for substitution.

Q: What is the primary difference between these two parts?

A: The MIC4576BU TR is obsolete, while the MIC4576WU TR maintains active product status. Additionally, the MIC4576WU TR is ROHS3 compliant, whereas the MIC4576BU TR is not. Electrical performance and thermal characteristics are identical.

Q: Are there any differences in packaging or tape configuration?

A: The MIC4576BU TR is supplied in Tape & Reel (TR) format. The MIC4576WU TR is supplied in Cut Tape (CT) and Digi-Reel format. Both use the same physical package (TO-263-6, D2PAK). Tape configuration does not affect component functionality or PCB assembly compatibility.

Q: Do both parts operate across the same input and output voltage ranges?

A: Yes. Both the MIC4576BU TR and MIC4576WU TR operate with input voltage from 4V to 36V and support adjustable output voltage from 1.23V to 33V. Output current capability is 3A for both parts.

Q: Is the switching frequency identical between these parts?

A: Yes. Both parts operate at a fixed switching frequency of 200kHz.

Q: What is the moisture sensitivity level for these components?

A: Both parts have a Moisture Sensitivity Level (MSL) of 3, with a floor life of 168 hours.

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