LMS1587CT-ADJ Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LMS1587CT-ADJ is a linear voltage regulator IC from Texas Instruments designed for positive adjustable output applications. It delivers 3A output current in a TO-220-3 package and supports input voltages up to 13V with adjustable output ranging from 1.25V to 11.7V. The device is marked as "Not For New Designs," making identification of suitable alternatives essential for ongoing production and maintenance applications. This status indicates the part is obsolete or being phased out, necessitating equivalent substitutes for system continuity.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Part Number	LMS1587CT-ADJ
Category	Power Management (PMIC)
Package / Case	TO-220-3
Output Configuration	Positive
Output Type	Adjustable
Current - Output	3A
Voltage - Input (Max)	13V
Voltage - Output (Min/Fixed)	1.25V
Voltage - Output (Max)	11.7V
Voltage Dropout (Max)	1.3V @ 3A
Operating Temperature	0°C ~ 125°C
Mounting Type	Through Hole
Product Status	Not For New Designs

Substitute Part Grouping Explanation

Substitution for the LMS1587CT-ADJ is determined by strict alignment of the following electrical and mechanical parameters:

Package / Case: TO-220-3 (through-hole mounting)
Output Configuration: Positive adjustable
Current - Output: 3A minimum
Voltage - Input (Max): 13V or greater
Voltage - Output Range: 1.25V minimum to 11.7V maximum
Voltage Dropout (Max): 1.3V @ 3A or lower
Operating Temperature: 0°C ~ 125°C
Protection Features: Over Current and Over Temperature minimum

Substitute parts must maintain compatibility across all these parameters to ensure direct functional replacement without circuit redesign.

Parameter Comparison

Parameter	LMS1587CT-ADJ	LMS1587CT-ADJ/NOPB	LT1587CT#PBF
Manufacturer	Texas Instruments	Texas Instruments	Linear Technology
Product Status	Not For New Designs	Active	Active
Package / Case	TO-220-3	TO-220-3	TO-220-3
Output Configuration	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable
Current - Output	3A	3A	3A
Voltage - Input (Max)	13V	13V	7V
Voltage - Output (Min/Fixed)	1.25V	1.25V	1.25V
Voltage - Output (Max)	11.7V	11.7V	5.5V
Voltage Dropout (Max)	1.3V @ 3A	1.3V @ 3A	1.3V @ 3A
Operating Temperature	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C
Protection Features	Over Current, Over Temperature	Over Current, Over Temperature	Over Current, Over Temperature, Short Circuit
RoHS Status	RoHS non-compliant	ROHS3 Compliant	Not specified

Engineering Selection Recommendations

LMS1587CT-ADJ/NOPB is the primary direct substitute. It maintains identical electrical specifications and TO-220-3 packaging while offering Active product status and ROHS3 compliance. The /NOPB suffix indicates lead-free construction with no plumbum (lead), making it suitable for applications requiring RoHS compliance. This part is the recommended replacement for the obsolete LMS1587CT-ADJ.

LT1587CT#PBF from Linear Technology is a secondary alternative with the same 3A output current, adjustable output topology, and identical dropout voltage. However, it has critical parameter limitations: maximum input voltage is 7V (versus 13V for the LMS1587CT-ADJ) and maximum output voltage is 5.5V (versus 11.7V). The LT1587CT#PBF is suitable only for applications operating within these reduced voltage ranges. It provides additional short-circuit protection not present in the LMS1587CT-ADJ.

Selection should prioritize LMS1587CT-ADJ/NOPB for direct replacement. Use LT1587CT#PBF only when input and output voltage requirements fall within its specified limits.

Frequently Asked Questions (FAQ)

Q: Can LMS1587CT-ADJ/NOPB directly replace LMS1587CT-ADJ without circuit modification?

A: Yes. Both parts share identical electrical specifications, output voltage range (1.25V to 11.7V), current rating (3A), dropout voltage (1.3V @ 3A), and TO-220-3 package. The /NOPB designation indicates lead-free construction and does not affect functional compatibility.

Q: What is the key limitation of LT1587CT#PBF as a substitute?

A: The LT1587CT#PBF has reduced maximum input voltage (7V versus 13V) and maximum output voltage (5.5V versus 11.7V). It is compatible only with applications operating within these lower voltage ranges. Verify your circuit's input and output voltage requirements before selecting this part.

Q: Why is LMS1587CT-ADJ marked "Not For New Designs"?

A: This status indicates the part is obsolete or being discontinued by the manufacturer. LMS1587CT-ADJ/NOPB is the active replacement and should be used for all new designs and ongoing production.

Q: Are there packaging differences between these substitutes?

A: All three parts use TO-220-3 through-hole packaging. No PCB layout modifications are required for substitution.

Q: What compliance differences exist between the substitutes?

A: LMS1587CT-ADJ/NOPB is ROHS3 compliant with lead-free construction. The original LMS1587CT-ADJ is RoHS non-compliant. The LT1587CT#PBF compliance status is not specified in the provided data.

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