LM350AT Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The LM350AT is a positive adjustable linear voltage regulator manufactured by Texas Instruments, designed for applications requiring 3A output current with adjustable voltage output from 1.25V to 33V. The device is packaged in TO-220-3 and currently holds Last Time Buy status, indicating end-of-life production. Finding equivalent and substitute parts is necessary to ensure design continuity and long-term supply chain reliability for new production runs and maintenance applications.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM350AT
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Package / Case	TO-220-3
Output Configuration	Positive
Output Type	Adjustable
Voltage - Input (Max)	35V
Voltage - Output (Min/Fixed)	1.25V
Voltage - Output (Max)	33V
Current - Output	3A
Operating Temperature	-40°C ~ 125°C
Protection Features	Over Current, Over Temperature, Short Circuit
RoHS Status	ROHS3 Compliant
Product Status	Last Time Buy

Substitute Part Grouping Explanation

Substitution of the LM350AT is determined by the following critical parameters:

Primary Substitution Criteria:

Output Configuration: Positive adjustable
Package / Case: TO-220-3 form factor
Output voltage range capability: minimum 1.25V or lower, maximum 33V or higher
Current output rating: must meet or exceed 3A requirement
Operating temperature range: must cover -40°C to 125°C or equivalent industrial range
Protection features: Over Current, Over Temperature, Short Circuit protection
RoHS3 compliance and regulatory alignment (REACH, ECCN)

Substitution Categories:

Direct Equivalent (Pin-Compatible, Identical Specifications): LM350AT/NOPB maintains identical electrical and mechanical specifications with active product status, making it a direct replacement.

Functional Equivalent (Reduced Current Rating): LM317BTG and LM317TG are manufacturer-recommended alternatives from onsemi. These devices provide positive adjustable regulation with identical package form factor but reduced output current (1.5A vs. 3A). Substitution is valid only for applications where the 1.5A current limit is acceptable. Both devices maintain the same voltage adjustment range (1.2V minimum output) and protection features.

Parameter Comparison

Parameter	LM350AT	LM350AT/NOPB	LM317BTG	LM317TG
Manufacturer	Texas Instruments	Texas Instruments	onsemi	onsemi
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Output Configuration	Positive	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable	Adjustable
Voltage - Input (Max)	35V	35V	40V	40V
Voltage - Output (Min)	1.25V	1.25V	1.2V	1.2V
Voltage - Output (Max)	33V	33V	37V	37V
Current - Output	3A	3A	1.5A	1.5A
PSRR	86dB ~ 65dB (120Hz)	86dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)	80dB ~ 65dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit	Over Current, Over Temperature, Short Circuit
Operating Temperature	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Last Time Buy	Active	Active	Active

Engineering Selection Recommendations

LM350AT/NOPB is the preferred substitute when supply of the original LM350AT is exhausted. This part maintains identical electrical specifications, current rating, and temperature range while offering active product status and continued manufacturer support. No design modifications are required for direct substitution.

LM317BTG and LM317TG are valid alternatives only when application current requirements do not exceed 1.5A. Both devices are actively manufactured by onsemi with established supply chains. The LM317BTG supports the full industrial temperature range (-40°C to 125°C), matching the original specification. The LM317TG operates from 0°C to 125°C, which may be limiting for applications requiring extended low-temperature operation below 0°C. All substitute options maintain ROHS3 compliance and equivalent protection features.

Frequently Asked Questions (FAQ)

Q: Can LM317BTG or LM317TG directly replace LM350AT in all applications?

A: Direct replacement is valid only if your application current requirement does not exceed 1.5A. The LM317 series devices are rated for 1.5A maximum output, while the LM350AT is rated for 3A. If your design draws more than 1.5A, the LM317 devices will not function properly and may trigger over-current protection. Verify your actual load current before substitution.

Q: What is the difference between LM317BTG and LM317TG?

A: Both devices are electrically identical with the same 1.5A output rating and voltage adjustment range. The primary difference is operating temperature range: LM317BTG operates from -40°C to 125°C (full industrial range), while LM317TG operates from 0°C to 125°C. Select LM317BTG if your application requires operation below 0°C.

Q: Is LM350AT/NOPB a true equivalent to LM350AT?

A: Yes. LM350AT/NOPB is the direct equivalent manufactured by Texas Instruments with identical electrical specifications, current rating, voltage range, and package. The "/NOPB" suffix indicates lead-free (Pb-free) manufacturing, which is standard for ROHS3 compliance. No design changes are required for substitution.

Q: Are all substitute parts available in the same TO-220-3 package?

A: Yes. LM350AT/NOPB, LM317BTG, and LM317TG are all packaged in TO-220-3, ensuring mechanical and thermal compatibility with existing PCB layouts and heat sink mounting arrangements.

Q: What compliance certifications apply to these substitute parts?

A: All listed parts are ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99. These certifications ensure regulatory compliance for industrial and commercial applications across major markets.

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