LMS1585ACT-3.3 Linear Voltage Regulator - Equivalent & Substitute Parts

Part Overview

The LMS1585ACT-3.3 is a linear voltage regulator IC manufactured by Texas Instruments, designed to deliver a fixed 3.3V output at 5A in a TO-220-3 package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The regulator provides positive fixed output configuration with integrated over-current and over-temperature protection suitable for power management applications requiring stable 3.3V rails.

Substiute Parts

LMS1585ACT-3.3

Texas InstrumentsIn Stock: 1420LMS1585ACT-3.3 Datasheet

Current PartRFQ

LMS1585ACT-3.3/NOPB

Texas InstrumentsIn Stock: 1457LMS1585ACT-3.3/NOPB Datasheet

DirectRFQ

LD1117V33

STMicroelectronicsIn Stock: 15597LD1117V33 Datasheet

MFR RecommendedRFQ

LD1117V33C

STMicroelectronicsIn Stock: 18037LD1117V33C Datasheet

MFR RecommendedRFQ

LT1585ACT-3.3#PBF

Analog Devices Inc.In Stock: 1282LT1585ACT-3.3#PBF Datasheet

MFR RecommendedRFQ

LT1585CT-3.3#PBF

Analog Devices Inc.In Stock: 1446LT1585CT-3.3#PBF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LMS1585ACT-3.3 are grouped based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

• Output voltage: 3.3V fixed
• Package type: TO-220-3 (mechanical and thermal compatibility)
• Output configuration: Positive fixed
• Protection features: Over-current and over-temperature protection
• Mounting type: Through-hole

Substitution Categories:

Category 1: Direct Equivalent (Same Manufacturer, Active Status) LMS1585ACT-3.3/NOPB is the direct equivalent from Texas Instruments with identical electrical specifications and active product status. This part differs only in packaging designation (NOPB indicates no lead-free plating).

Category 2: Higher Input Voltage Rating (STMicroelectronics) LD1117V33 and LD1117V33C from STMicroelectronics provide 3.3V fixed output in TO-220 package. These parts accept higher maximum input voltage (15V vs. 13V) but deliver reduced output current (800mA vs. 5A). Substitution is valid only for applications requiring less than 800mA output current.

Category 3: Matched Current Rating (Analog Devices Inc.) LT1585ACT-3.3#PBF and LT1585CT-3.3#PBF from Analog Devices Inc. maintain the 5A output current capability and TO-220-3 package. LT1585ACT-3.3#PBF delivers 5A; LT1585CT-3.3#PBF delivers 4.6A. Both accept lower maximum input voltage (7V vs. 13V) and include short-circuit protection in addition to over-current and over-temperature protection.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Recommended Primary Choice): LMS1585ACT-3.3/NOPB is the preferred substitute. It maintains identical electrical specifications and TO-220-3 package compatibility with the obsolete LMS1585ACT-3.3. This part carries active product status and ROHS3 compliance, eliminating obsolescence risk for new designs and production continuity.

For Current-Limited Applications (800mA Maximum): LD1117V33 or LD1117V33C from STMicroelectronics are suitable substitutes only when application requirements do not exceed 800mA output current. Both parts are ROHS3 compliant and actively produced. LD1117V33C extends operating temperature range to -40°C ~ 125°C, providing advantage for extended temperature applications.

For Input Voltage-Constrained Applications (7V Maximum Input): LT1585ACT-3.3#PBF and LT1585CT-3.3#PBF from Analog Devices Inc. are suitable only when maximum input voltage does not exceed 7V. LT1585ACT-3.3#PBF maintains full 5A output current; LT1585CT-3.3#PBF delivers 4.6A. Both include short-circuit protection and are ROHS3 compliant with active product status.

Compliance Consideration: All substitute parts listed carry ROHS3 compliance, addressing regulatory requirements absent in the obsolete LMS1585ACT-3.3. This compliance status is mandatory for new designs in regulated markets.

Frequently Asked Questions (FAQ)

Q: Can LMS1585ACT-3.3/NOPB directly replace LMS1585ACT-3.3 without circuit modification? A: Yes. LMS1585ACT-3.3/NOPB is electrically and mechanically identical to the obsolete LMS1585ACT-3.3. Both deliver 5A at 3.3V in TO-220-3 package with identical dropout voltage and protection features. No circuit changes are required.

Q: Why do LD1117V33 and LD1117V33C have lower output current ratings? A: The LD1117 series is designed for lower current applications (800mA maximum). These parts are suitable substitutes only for circuits requiring output current below 800mA. Applications requiring 5A output current must use LMS1585ACT-3.3/NOPB or Analog Devices LT1585 series.

Q: What is the difference between LD1117V33 and LD1117V33C? A: Both deliver 3.3V at 800mA in TO-220 package. LD1117V33C extends operating temperature range to -40°C ~ 125°C compared to LD1117V33 (0°C ~ 125°C). LD1117V33C is the preferred choice for applications requiring extended low-temperature operation.

Q: Can LT1585ACT-3.3#PBF and LT1585CT-3.3#PBF substitute for LMS1585ACT-3.3 in all applications? A: These parts are suitable substitutes only when maximum input voltage does not exceed 7V. The LMS1585ACT-3.3 accepts input voltage up to 13V. Applications with input voltage between 7V and 13V require LMS1585ACT-3.3/NOPB or LD1117 series (if current is limited to 800mA).

Q: Are all substitute parts RoHS compliant? A: Yes. All listed substitute parts carry ROHS3 compliance. The original LMS1585ACT-3.3 is RoHS non-compliant. Substitution with any listed part addresses RoHS compliance requirements for new designs.

Q: Do all substitute parts use the same TO-220-3 package? A: Yes. All substitute parts use TO-220-3 package, ensuring mechanical and thermal compatibility with existing PCB layouts and thermal management designs. No board redesign is required for package accommodation.

Q: Which substitute part offers the best overall compatibility? A: LMS1585ACT-3.3/NOPB from Texas Instruments provides the best overall compatibility. It maintains identical electrical specifications, output current rating, input voltage range, and package type as the obsolete original part while offering active product status and RoHS compliance.