LM2591HVT-3.3 Equivalent & Substitute Parts

Part Overview

The LM2591HVT-3.3 is a buck switching regulator IC from Texas Instruments, rated for 3.3V fixed output at 1A current capacity in a TO-220-5 package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain compatibility across input voltage range, output voltage specification, current rating, and package form factor while meeting modern compliance standards.

Key Parameters

Parameter	LM2591HVT-3.3
Manufacturer	Texas Instruments
Function	Step-Down (Buck)
Output Voltage	3.3V Fixed
Output Current	1A
Input Voltage Range	4.5V to 60V
Switching Frequency	150kHz
Package	TO-220-5 Formed Leads
Operating Temperature	-40°C to 125°C (TJ)
Product Status	Obsolete
RoHS Status	RoHS Non-Compliant

Substitute Part Grouping Explanation

Substitution logic for the LM2591HVT-3.3 is based on the following critical parameters:

Primary Substitution Criteria:

Output voltage: 3.3V fixed
Package form factor: TO-220-5
Mounting type: Through-hole
Output configuration: Positive
Topology: Buck (step-down)

Secondary Compatibility Parameters:

Input voltage range must encompass or exceed the minimum 4.5V requirement
Output current rating must meet or exceed 1A
Operating temperature range: -40°C to 125°C
RoHS and REACH compliance status

Substitute parts are grouped into two categories: direct equivalents (matching 1A output current) and higher-capacity alternatives (3A output current). Higher-capacity parts are electrically compatible as they can deliver the required 1A while providing additional headroom for design margin.

Parameter Comparison

Parameter	LM2591HVT-3.3	LM2591HVT-3.3/NOPB	LM2575T-3.3G	LM2576-3.3WT	LM2576T-3.3G	MIC4575-3.3WT	MIC4576-3.3WT
Manufacturer	Texas Instruments	Texas Instruments	onsemi	Microchip Technology	onsemi	Microchip Technology	Microchip Technology
Output Voltage	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V	3.3V
Output Current	1A	1A	1A	3A	3A	1.7A (Switch)	3A
Input Voltage (Min)	4.5V	4.5V	4.75V	4V	7V	4V	4V
Input Voltage (Max)	60V	60V	40V	40V	40V	24V	36V
Switching Frequency	150kHz	150kHz	52kHz	52kHz	52kHz	200kHz	200kHz
Package	TO-220-5	TO-220-5	TO-220-5	TO-220-5	TO-220-5	TO-220-5	TO-220-5
Operating Temperature	-40°C to 125°C	-40°C to 125°C	-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
Product Status	Obsolete	Active	Active	Active	Obsolete	Active	Active
RoHS Status	Non-Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalent (Recommended Primary Choice): LM2591HVT-3.3/NOPB from Texas Instruments is the direct equivalent with identical electrical specifications and active product status. This part maintains the same 150kHz switching frequency, 1A output current, and 4.5V to 60V input range. It achieves ROHS3 compliance and is available in higher inventory quantities (2100 pcs), making it the preferred choice for designs requiring exact parameter matching and modern compliance certification.

Alternative 1A Substitutes: LM2575T-3.3G (onsemi) provides 1A output current with active status and ROHS3 compliance. Input voltage range is 4.75V to 40V with 52kHz switching frequency. This part is suitable where the reduced maximum input voltage (40V vs. 60V) and lower switching frequency do not conflict with application requirements.

Higher-Current Alternatives (3A Output): LM2576-3.3WT (Microchip Technology) and MIC4576-3.3WT (Microchip Technology) both deliver 3A output current in TO-220-5 packages with active product status and ROHS3 compliance. These parts provide design margin for applications requiring sustained 1A operation with thermal headroom. LM2576-3.3WT supports 4V to 40V input range at 52kHz, while MIC4576-3.3WT operates from 4V to 36V at 200kHz. Both maintain -40°C to 125°C operating temperature range.

Compliance Consideration: All recommended active substitutes achieve ROHS3 compliance, addressing the non-compliant status of the obsolete LM2591HVT-3.3. This is critical for new designs and production environments with regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can LM2591HVT-3.3/NOPB be used as a direct replacement for LM2591HVT-3.3? A: Yes. Both parts share identical electrical specifications: 3.3V output, 1A current, 4.5V to 60V input range, 150kHz switching frequency, and TO-220-5 package. The primary difference is product status (active vs. obsolete) and RoHS compliance (ROHS3 vs. non-compliant). The /NOPB variant is the recommended choice for new designs.

Q: What is the difference between 1A and 3A output current substitutes? A: The LM2591HVT-3.3 is rated for 1A output. Substitutes rated for 3A (LM2576-3.3WT, MIC4576-3.3WT) can deliver the required 1A while providing additional thermal margin and design headroom. They are electrically compatible but occupy the same package footprint. Selection depends on thermal management requirements and available board space for heat dissipation.

Q: Are there input voltage range limitations with substitute parts? A: Yes. The original LM2591HVT-3.3 supports 4.5V to 60V input. LM2575T-3.3G reduces the maximum to 40V. LM2576T-3.3G requires minimum 7V input (vs. 4.5V). MIC4575-3.3WT and MIC4576-3.3WT limit maximum input to 24V and 36V respectively. Verify application input voltage requirements before selection.

Q: Do substitute parts maintain the same switching frequency? A: No. The original operates at 150kHz. LM2575T-3.3G, LM2576-3.3WT, and LM2576T-3.3G operate at 52kHz. MIC4575-3.3WT and MIC4576-3.3WT operate at 200kHz. Switching frequency affects output ripple, EMI characteristics, and inductor/capacitor selection. Verify compatibility with existing filter designs.

Q: Are all substitute parts RoHS compliant? A: All active substitute parts listed (LM2591HVT-3.3/NOPB, LM2575T-3.3G, LM2576-3.3WT, MIC4575-3.3WT, MIC4576-3.3WT) achieve ROHS3 compliance. The original LM2591HVT-3.3 is non-compliant. This is a key advantage of substitution for new production and regulated environments.

Q: Can MIC4575-3.3WT be used despite its lower maximum input voltage (24V)? A: MIC4575-3.3WT is compatible only if application input voltage does not exceed 24V. This part also operates at -40°C to 85°C (vs. -40°C to 125°C for other options), which may be a constraint in high-temperature environments. Verify both input voltage and operating temperature requirements before selection.

Q: What is the significance of the TO-220-5 package across all parts? A: All listed parts use TO-220-5 package with identical pin configuration and through-hole mounting. This ensures mechanical and electrical compatibility without PCB redesign. Thermal performance may vary based on die design and internal layout, but package footprint and pinout remain consistent.

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