MIC39301-1.8BU TR Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The MIC39301-1.8BU TR is a linear voltage regulator IC from Microchip Technology designed to deliver a fixed 1.8V output at 3A maximum current in a TO-263-5 surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and production continuity. The regulator provides positive fixed output with integrated over-current, over-temperature, and reverse polarity protection, suitable for applications requiring stable 1.8V power delivery with moderate current demands.

Key Parameters

Parameter	Value
Manufacturer	Microchip Technology
Part Number	MIC39301-1.8BU TR
Output Voltage (Fixed)	1.8V
Output Current	3A
Input Voltage (Max)	16V
Dropout Voltage @ 3A	0.55V
Package	TO-263-5 (D2PAK)
Operating Temperature	-40°C to 125°C
Protection Features	Over Current, Over Temperature, Reverse Polarity
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution for the MIC39301-1.8BU TR is determined by the following critical parameters:

Primary Substitution Criteria:

Fixed output voltage of 1.8V
Output current capability of 3A or greater
TO-263-5 (D2PAK) package compatibility
Operating temperature range of -40°C to 125°C
Enable control feature
Protection against over-current and over-temperature conditions

Substitution Categories:

Category 1: Direct Microchip Equivalents (Active Status) MIC39301-1.8WU-TR is the active production equivalent from Microchip Technology with identical electrical specifications and package. This part maintains full compatibility with the obsolete MIC39301-1.8BU TR while offering RoHS3 compliance.

Category 2: Texas Instruments 3A Regulators LP3853ES-1.8/NOPB and LP3853ESX-1.8/NOPB deliver 3A output current in TO-263 (DDPAK-5) package with 1.8V fixed output. These parts feature lower input voltage maximum (7V vs. 16V) but maintain equivalent output current and thermal performance.

Category 3: Texas Instruments 1.5A Regulators LP3965ES-1.8/NOPB and LP3965ESX-1.8/NOPB provide 1.5A output current, representing a reduced-current alternative suitable for applications not requiring full 3A capacity. These parts share the same 1.8V output and TO-263 package footprint.

Category 4: Analog Devices 3A Regulators LT1764AEQ-1.8#PBF, LT1764AEQ-1.8#TRPBF, and LT1764EQ-1.8#TRPBF deliver 3A output with 1.8V fixed output in DDPAK-5 package. These parts support higher input voltage (20V maximum) and feature lower quiescent current (1.5 mA).

Category 5: Analog Devices 1.5A Regulators LT1963AEQ-1.8#PBF and LT1963AEQ-1.8#TRPBF provide 1.5A output current with 1.8V fixed output in DDPAK-5 package, offering reduced current capacity with improved quiescent current performance.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Dropout @ Rated Current	Package	Product Status	RoHS Status	Quiescent Current
MIC39301-1.8BU TR	Microchip	3A	16V	0.55V @ 3A	TO-263-5	Obsolete	Non-compliant	—
MIC39301-1.8WU-TR	Microchip	3A	16V	0.55V @ 3A	TO-263-5	Active	ROHS3 Compliant	—
LP3853ES-1.8/NOPB	Texas Instruments	3A	7V	0.6V @ 3A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant	4 mA
LP3853ESX-1.8/NOPB	Texas Instruments	3A	7V	0.6V @ 3A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant	4 mA
LP3965ES-1.8/NOPB	Texas Instruments	1.5A	7V	0.55V @ 1.5A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant	9 mA
LP3965ESX-1.8/NOPB	Texas Instruments	1.5A	7V	0.55V @ 1.5A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant	9 mA
LT1764AEQ-1.8#PBF	Analog Devices	3A	20V	0.66V @ 3A	DDPAK-5	Active	ROHS3 Compliant	1.5 mA
LT1764AEQ-1.8#TRPBF	Analog Devices	3A	20V	0.66V @ 3A	DDPAK-5	Active	ROHS3 Compliant	1.5 mA
LT1764EQ-1.8#TRPBF	Analog Devices	3A	20V	0.66V @ 3A	DDPAK-5	Active	ROHS3 Compliant	1.5 mA
LT1963AEQ-1.8#PBF	Analog Devices	1.5A	20V	0.55V @ 1.5A	DDPAK-5	Active	ROHS3 Compliant	1.5 mA
LT1963AEQ-1.8#TRPBF	Analog Devices	1.5A	20V	0.55V @ 1.5A	DDPAK-5	Active	ROHS3 Compliant	1.5 mA

Engineering Selection Recommendations

For Direct Replacement (Recommended Primary Choice): MIC39301-1.8WU-TR is the preferred substitute, offering identical electrical specifications and package compatibility with the obsolete MIC39301-1.8BU TR. This part is in active production status and achieves RoHS3 compliance, making it suitable for new designs and production environments requiring regulatory compliance.

For 3A Output Requirement with Lower Input Voltage: LP3853ES-1.8/NOPB and LP3853ESX-1.8/NOPB maintain the 3A output current specification but operate with a maximum input voltage of 7V. These parts are appropriate for applications where input voltage does not exceed 7V and where RoHS3 compliance is required. The tape-and-reel variant (LP3853ESX-1.8/NOPB) is suitable for automated assembly processes.

For 3A Output with Extended Input Voltage Range: LT1764AEQ-1.8#TRPBF and LT1764EQ-1.8#TRPBF support input voltages up to 20V while maintaining 3A output current. These parts offer superior quiescent current performance (1.5 mA) and are available in cut-tape and digi-reel packaging for flexible procurement. RoHS3 compliance is achieved across all variants.

For Reduced Current Applications (1.5A): LP3965ESX-1.8/NOPB and LT1963AEQ-1.8#TRPBF provide 1.5A output current alternatives. Selection between these depends on input voltage requirements: LP3965ESX-1.8/NOPB for applications with input voltage not exceeding 7V, or LT1963AEQ-1.8#TRPBF for applications requiring input voltage up to 20V.

Compliance Considerations: All recommended substitutes achieve RoHS3 compliance, addressing the non-compliant status of the original MIC39301-1.8BU TR. For applications requiring REACH compliance verification, LP3853ESX-1.8/NOPB is marked as REACH Affected, while all other substitutes are REACH Unaffected.

Frequently Asked Questions (FAQ)

Q: Can MIC39301-1.8WU-TR be used as a direct drop-in replacement for MIC39301-1.8BU TR? A: Yes. MIC39301-1.8WU-TR provides identical electrical specifications, output voltage, output current, and package configuration. The primary difference is active production status and RoHS3 compliance. No circuit modifications are required.

Q: What is the difference between LP3853ES-1.8/NOPB and LP3853ESX-1.8/NOPB? A: Both parts are electrically identical with 3A output at 1.8V. The primary difference is packaging: LP3853ES-1.8/NOPB is supplied in tube packaging, while LP3853ESX-1.8/NOPB is supplied in tape-and-reel format suitable for automated assembly. Select based on procurement and assembly requirements.

Q: Why do some substitutes have lower maximum input voltage (7V vs. 16V)? A: Texas Instruments LP3853 and LP3965 series regulators are designed for lower input voltage applications. If your circuit requires input voltages above 7V, select Analog Devices LT1764 or LT1963 series (20V maximum) or Microchip MIC39301-1.8WU-TR (16V maximum).

Q: Can I use a 1.5A regulator (LP3965 or LT1963) instead of a 3A regulator? A: Only if your application requires maximum output current of 1.5A or less. If your circuit draws more than 1.5A, the regulator will enter current-limit protection. Verify actual current requirements before selecting a reduced-current substitute.

Q: Are all substitute parts RoHS3 compliant? A: Yes. All recommended substitutes achieve RoHS3 compliance. The original MIC39301-1.8BU TR is RoHS non-compliant. If regulatory compliance is required, any of the recommended substitutes satisfy this requirement.

Q: What is the difference between cut-tape and tape-and-reel packaging? A: Cut-tape (CT) and digi-reel packaging (indicated by #TRPBF suffix) are suitable for manual or semi-automated assembly. Standard tape-and-reel (TR) packaging is optimized for high-volume automated assembly. Select based on your assembly process requirements.

Q: Do all substitutes support the same operating temperature range? A: Yes. All recommended substitutes operate across -40°C to 125°C, matching the original MIC39301-1.8BU TR specification.

Q: What is quiescent current and why does it vary between substitutes? A: Quiescent current is the current consumed by the regulator itself when no load is connected. Lower quiescent current reduces standby power consumption. Analog Devices LT1764 and LT1963 series feature 1.5 mA quiescent current, while Texas Instruments LP3853 and LP3965 series feature 4 mA and 9 mA respectively. Select based on standby power budget requirements.

Q: Can I use LT1764AEQ-1.8#TRPBF in a design originally specified for MIC39301-1.8BU TR? A: Yes, with verification of input voltage requirements. LT1764AEQ-1.8#TRPBF supports input voltages up to 20V (vs. 16V for the original), maintains 3A output current, and uses compatible DDPAK-5 package. The higher input voltage rating provides additional design margin.

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