MIC39151-1.8BU Equivalent & Substitute Parts

Part Overview

The MIC39151-1.8BU is a linear voltage regulator IC from Microchip Technology, delivering a fixed 1.8V output at 1.5A in a TO-263-5 surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The regulator features enable control, over-current protection, over-temperature protection, and reverse polarity protection, with a maximum input voltage of 16V and dropout voltage of 0.5V at 1.5A.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	1.8V
Output Current	1.5A
Input Voltage (Max)	16V
Dropout Voltage (Max)	0.5V @ 1.5A
Package Type	TO-263-5 (D2PAK)
Operating Temperature Range	-40°C to 125°C
Protection Features	Over Current, Over Temperature, Reverse Polarity
Control Features	Enable

Substitute Part Grouping Explanation

Substitution for the MIC39151-1.8BU is determined by the following critical parameters:

Fixed output voltage of 1.8V
Output current capability of 1.5A 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

Substitute parts are grouped into two categories:

Category 1: Direct Microchip Equivalent — MIC39151-1.8WU maintains identical electrical specifications and differs only in packaging format (Tube vs. standard packaging) and product status (Active vs. Obsolete).

Category 2: Cross-Manufacturer Alternatives — Texas Instruments LP39xx and LP39xx series, and Analog Devices LT1764 series meet the core electrical requirements with compatible package footprints. These parts may have different input voltage maximums, dropout characteristics, or quiescent current specifications, but maintain the essential 1.8V fixed output, 1.5A minimum current capability, and TO-263-5 package form factor.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout Voltage (Max)	Package	Product Status	RoHS Status
MIC39151-1.8BU	Microchip Technology	1.8V	1.5A	16V	0.5V @ 1.5A	TO-263-5	Obsolete	Non-compliant
MIC39151-1.8WU	Microchip Technology	1.8V	1.5A	16V	0.5V @ 1.5A	TO-263-5	Active	ROHS3 Compliant
LP3962ES-1.8/NOPB	Texas Instruments	1.8V	1.5A	7V	0.55V @ 1.5A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant
LP3962ESX-1.8/NOPB	Texas Instruments	1.8V	1.5A	7V	0.55V @ 1.5A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant
LP3965ES-1.8/NOPB	Texas Instruments	1.8V	1.5A	7V	0.55V @ 1.5A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant
LP3965ESX-1.8/NOPB	Texas Instruments	1.8V	1.5A	7V	0.55V @ 1.5A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant
LP3966ES-1.8/NOPB	Texas Instruments	1.8V	3A	7V	1.2V @ 3A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant
LP3966ESX-1.8/NOPB	Texas Instruments	1.8V	3A	7V	1.2V @ 3A	TO-263 (DDPAK-5)	Active	ROHS3 Compliant
LT1764AEQ-1.8#PBF	Analog Devices Inc.	1.8V	3A	20V	0.66V @ 3A	DDPAK-5	Active	ROHS3 Compliant
LT1764AEQ-1.8#TRPBF	Analog Devices Inc.	1.8V	3A	20V	0.66V @ 3A	DDPAK-5	Active	ROHS3 Compliant
LT1764EQ-1.8#TRPBF	Analog Devices Inc.	1.8V	3A	20V	0.66V @ 3A	DDPAK-5	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: MIC39151-1.8WU

The MIC39151-1.8WU is the direct active equivalent of the obsolete MIC39151-1.8BU. It maintains identical electrical specifications, package footprint, and pinout. The primary advantage is active product status with ROHS3 compliance, ensuring long-term availability and regulatory alignment for new designs.

Secondary Recommendations: Texas Instruments LP39xx Series

The LP3962ES-1.8/NOPB, LP3962ESX-1.8/NOPB, LP3965ES-1.8/NOPB, and LP3965ESX-1.8/NOPB are functionally equivalent at the 1.5A output current level. These parts are active, ROHS3 compliant, and available in multiple packaging formats (Tube, Cut Tape & Digi-Reel, Tape & Reel). The primary design consideration is the reduced maximum input voltage (7V vs. 16V), which limits application in higher input voltage systems.

Higher Current Alternative: Texas Instruments LP3966 Series

The LP3966ES-1.8/NOPB and LP3966ESX-1.8/NOPB provide 3A output current capability in the same TO-263 package. These are suitable for designs requiring higher current delivery while maintaining the 1.8V fixed output. Input voltage is limited to 7V maximum.

Premium Alternative: Analog Devices LT1764 Series

The LT1764AEQ-1.8#PBF, LT1764AEQ-1.8#TRPBF, and LT1764EQ-1.8#TRPBF deliver 3A output current with a maximum input voltage of 20V, matching the original MIC39151-1.8BU input specification. These parts feature lower quiescent current (1.5 mA vs. unspecified), superior PSRR (63dB at 120Hz), and MSL rating of 1 (Unlimited). All variants are active and ROHS3 compliant.

Frequently Asked Questions (FAQ)

Q: Can I use LP3962ES-1.8/NOPB as a direct replacement for MIC39151-1.8BU?

A: The LP3962ES-1.8/NOPB is electrically compatible at the 1.5A output current level and uses the same TO-263 package footprint. However, the maximum input voltage is reduced from 16V to 7V. If your application operates within 7V input, this part is suitable. If higher input voltages are required, use the LT1764 series instead.

Q: What is the difference between LP3965ES-1.8/NOPB and LP3965ESX-1.8/NOPB?

A: Both parts have identical electrical specifications. The difference is packaging format: LP3965ES-1.8/NOPB is supplied in Tube packaging, while LP3965ESX-1.8/NOPB is supplied in Tape & Reel (TR) format. Select based on your procurement and assembly requirements.

Q: Why would I choose LT1764 over MIC39151-1.8WU?

A: The LT1764 series offers higher output current (3A vs. 1.5A), higher maximum input voltage (20V vs. 16V), and superior quiescent current performance (1.5 mA). Choose LT1764 if your design requires higher current delivery or operates at higher input voltages. For equivalent 1.5A applications within 16V input, MIC39151-1.8WU is the simpler choice.

Q: Are all substitute parts ROHS3 compliant?

A: All recommended substitute parts are ROHS3 compliant. The original MIC39151-1.8BU is RoHS non-compliant. If RoHS compliance is required for your application, use MIC39151-1.8WU or any of the cross-manufacturer alternatives.

Q: Can I use LP3966ES-1.8/NOPB (3A) in place of MIC39151-1.8BU (1.5A)?

A: Yes. The LP3966ES-1.8/NOPB is backward compatible for 1.5A applications. The higher current rating provides design margin and future scalability. The same input voltage limitation (7V maximum) applies.

Q: What is the package compatibility between TO-263-5 and DDPAK-5?

A: TO-263-5 and DDPAK-5 are equivalent designations for the same physical package: a 5-lead surface mount package with a thermal tab. All substitute parts listed use this package family and are footprint compatible with the original MIC39151-1.8BU.

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