LM317H Linear Voltage Regulator IC Equivalent & Substitute Parts

Part Overview

The LM317H is an active linear voltage regulator IC from Texas Instruments, classified as a Power Management (PMIC) component. It provides positive adjustable output voltage regulation with 1.5A output current capability in a TO-3 metal can package. The device is currently in active product status with 2200 units in stock. Alternative equivalent parts are necessary to address supply chain flexibility, packaging preferences, and application-specific requirements while maintaining electrical and mechanical compatibility.

Key Parameters

Parameter	Value
Output Configuration	Positive
Output Type	Adjustable
Number of Regulators	1
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	1.25V
Voltage - Output (Max)	37V
Current - Output	1.5A
Current - Quiescent (Iq)	10 mA
PSRR	80dB ~ 65dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit
Operating Temperature	0°C ~ 125°C
Mounting Type	Through Hole
Package / Case	TO-205AD, TO-39-3 Metal Can
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the LM317H is determined by the following critical parameters:

Electrical Compatibility Criteria:

Output configuration must be positive adjustable
Input voltage maximum rating must be 40V or greater
Output voltage range must encompass 1.25V to 37V
Output current capability must meet or exceed application requirements
Protection features must include over current, over temperature, and short circuit protection
Operating temperature range must cover 0°C to 125°C

Mechanical Compatibility Criteria:

Mounting type must be through hole
Package must be compatible with TO-3, TO-39-3, or TO-220 metal can configurations
Base product number must be LM317 series

Compliance Criteria:

RoHS3 compliance required
REACH unaffected status required
ECCN classification EAR99

Substitute parts are grouped into two categories: parametric equivalents (identical electrical specifications and pin-compatible packages) and manufacturer-recommended alternatives (functionally equivalent with different output current ratings and package options).

Parameter Comparison

Parameter	LM317H (Texas Instruments)	LM317H/NOPB (National Semiconductor)	LM317H (National Semiconductor)	LM317MTG (onsemi)
Manufacturer	Texas Instruments	National Semiconductor	National Semiconductor	onsemi
Output Configuration	Positive	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable	Adjustable
Voltage - Input (Max)	40V	40V	40V	40V
Voltage - Output (Min/Fixed)	1.25V	1.25V	1.25V	1.2V
Voltage - Output (Max)	37V	37V	37V	37V
Current - Output	1.5A	1.5A	1.5A	500mA
Current - Quiescent (Iq)	10 mA	Not specified	10 mA	10 mA
PSRR	80dB ~ 65dB (120Hz)	80dB ~ 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	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C (TJ)
Package / Case	TO-205AD, TO-39-3 Metal Can	TO-205AD, TO-39-3 Metal Can	TO-205AD, TO-39-3 Metal Can	TO-220-3
Supplier Device Package	TO-3	TO-39-3	TO-3	TO-220
RoHS Status	ROHS3 Compliant	Not specified	Not specified	ROHS3 Compliant
Inventory	2200 Pcs	5968 Pcs	2200 Pcs	9660 Pcs

Engineering Selection Recommendations

Parametric Equivalents (Full Compatibility):

LM317H/NOPB (National Semiconductor) and LM317H (National Semiconductor) are parametric equivalents to the primary LM317H (Texas Instruments). These parts maintain identical electrical specifications including 1.5A output current, 40V maximum input voltage, and 1.25V to 37V output voltage range. Both are ROHS3 compliant and carry active product status. Selection between these equivalents depends on packaging preference: LM317H/NOPB is supplied in bulk packaging with TO-39-3 device package, while the National Semiconductor LM317H variant is supplied in TO-3 device package. Both support through-hole mounting and provide equivalent thermal and electrical performance.

Manufacturer-Recommended Alternative:

LM317MTG (onsemi) is a manufacturer-recommended alternative suitable for applications where output current requirements do not exceed 500mA. This part differs from the primary LM317H in output current capability (500mA versus 1.5A) and package configuration (TO-220 versus TO-3/TO-39-3). The LM317MTG maintains all other critical electrical parameters including 40V maximum input voltage, 1.2V minimum output voltage, and identical protection features. The TO-220 package provides enhanced thermal dissipation compared to metal can packages. This alternative is appropriate only for current-limited applications and requires PCB layout modifications to accommodate the different package footprint.

Compliance and Product Status:

All substitute parts maintain active product status and ROHS3 compliance. The LM317 base product number ensures functional equivalence across all variants. Selection should prioritize parts with confirmed ROHS3 compliance status and active inventory availability.

Frequently Asked Questions (FAQ)

Q: Can LM317MTG replace LM317H in all applications?

A: LM317MTG is suitable only for applications requiring maximum output current of 500mA or less. Applications requiring 1.5A output current must use LM317H, LM317H/NOPB, or equivalent 1.5A variants. The TO-220 package of LM317MTG also requires different PCB layout and mounting considerations compared to the metal can packages.

Q: What is the difference between LM317H and LM317H/NOPB?

A: Both parts are parametric equivalents with identical electrical specifications. The primary difference is packaging: LM317H/NOPB is supplied in bulk packaging with TO-39-3 device package, while LM317H is supplied in TO-3 device package. Both support through-hole mounting and deliver equivalent performance.

Q: Are all substitute parts ROHS3 compliant?

A: LM317H (Texas Instruments) and LM317MTG (onsemi) carry confirmed ROHS3 compliance. ROHS3 compliance status for National Semiconductor variants is not specified in the provided data. Verification with the supplier is recommended for applications requiring certified ROHS3 compliance.

Q: Can I use TO-220 package LM317MTG on a PCB designed for TO-3 metal can?

A: No. The TO-220 package has a different pin configuration and footprint than TO-3 or TO-39-3 metal can packages. PCB layout and mounting hardware modifications are required. Direct mechanical substitution is not possible without redesign.

Q: What are the key parameters that determine substitution eligibility?

A: Substitution eligibility is determined by: output configuration (positive adjustable), input voltage rating (40V maximum), output voltage range (1.25V to 37V minimum), output current capability (must meet application requirements), protection features (over current, over temperature, short circuit), operating temperature range (0°C to 125°C), and through-hole mounting type. Package compatibility and compliance certifications must also be verified.

Q: Is the 1.2V minimum output voltage of LM317MTG compatible with applications designed for 1.25V?

A: The 1.2V minimum output voltage of LM317MTG is lower than the 1.25V specification of LM317H variants. For applications with output voltage set points at or near 1.25V, this difference may be within acceptable tolerance. However, applications with tight output voltage specifications should verify compatibility with the specific regulator design and feedback network used.

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