LM317LZX Equivalent & Substitute Parts

Part Overview

The LM317LZX is a linear voltage regulator IC from onsemi designed for positive adjustable output applications with 100mA current capability in a TO-92-3 package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and production continuity. The LM317LZX provides adjustable output voltage regulation from 1.2V to 37V with integrated protection features including over-current, over-temperature, and short-circuit protection.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM317LZX
Manufacturer	onsemi
Category	Power Management (PMIC)
Package / Case	TO-226-3, TO-92-3 (TO-226AA) Formed Leads
Output Configuration	Positive
Output Type	Adjustable
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	1.2V
Voltage - Output (Max)	37V
Current - Output	100mA
Current - Quiescent (Iq)	10 mA
PSRR	80dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit
Operating Temperature	0°C ~ 125°C
Mounting Type	Through Hole
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the LM317LZX is determined by strict alignment of the following electrical and mechanical parameters:

Critical Substitution Parameters:

Output Configuration: Positive
Output Type: Adjustable
Voltage - Input (Max): 40V
Voltage - Output Range: 1.2V to 37V
Current - Output: 100mA
Protection Features: Over Current, Over Temperature, Short Circuit
Package / Case: TO-226-3, TO-92-3 (TO-92 compatible)
Mounting Type: Through Hole

Substitute Categories:

Direct Substitutes (Identical Electrical & Mechanical Specifications):

LM317LBZRAG (onsemi) - Active product status
LM317LZRAG (onsemi) - Active product status
LM317LBZRPG (onsemi) - Active product status
LM317LZG (onsemi) - Active product status
LM317LZREG (onsemi) - Active product status
LM317LZRMG (onsemi) - Active product status
LM317LZRPG (onsemi) - Active product status

Automotive Grade Substitute (Extended Temperature Range):

NCV317LBZRAG (onsemi) - AEC-Q100 qualified, -40°C ~ 125°C operating range

Cross-Manufacturer Substitute (Different Manufacturer, Similar Specifications):

LM317LCLPR (Texas Instruments) - Last Time Buy status, slightly reduced output voltage maximum (32V vs 37V)
LM317LCLPRE3 (Texas Instruments) - Last Time Buy status, slightly reduced output voltage maximum (32V vs 37V)

Parameter Comparison

Part Number	Manufacturer	Product Status	Voltage Input (Max)	Voltage Output (Min/Max)	Current Output	Iq (mA)	Operating Temp	Package	RoHS Status
LM317LZX	onsemi	Obsolete	40V	1.2V / 37V	100mA	10	0°C ~ 125°C	TO-92-3	Not Specified
LM317LBZRAG	onsemi	Active	40V	1.2V / 37V	100mA	10	-40°C ~ 125°C	TO-92	ROHS3 Compliant
LM317LZRAG	onsemi	Active	40V	1.2V / 37V	100mA	10	0°C ~ 125°C	TO-92	ROHS3 Compliant
LM317LBZRPG	onsemi	Active	40V	1.2V / 37V	100mA	10	-40°C ~ 125°C	TO-92	ROHS3 Compliant
LM317LZG	onsemi	Active	40V	1.2V / 37V	100mA	10	0°C ~ 125°C	TO-92	ROHS3 Compliant
LM317LZREG	onsemi	Active	40V	1.2V / 37V	100mA	10	0°C ~ 125°C	TO-92	ROHS3 Compliant
LM317LZRMG	onsemi	Active	40V	1.2V / 37V	100mA	10	0°C ~ 125°C	TO-92	ROHS3 Compliant
LM317LZRPG	onsemi	Active	40V	1.2V / 37V	100mA	10	0°C ~ 125°C	TO-92	ROHS3 Compliant
NCV317LBZRAG	onsemi	Active	40V	1.2V / 37V	100mA	10	-40°C ~ 125°C	TO-92	ROHS3 Compliant
LM317LCLPR	Texas Instruments	Last Time Buy	38V	1.2V / 32V	100mA	2.5	0°C ~ 125°C	TO-92-3	ROHS3 Compliant
LM317LCLPRE3	Texas Instruments	Last Time Buy	38V	1.2V / 32V	100mA	2.5	0°C ~ 125°C	TO-92-3	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): Select from onsemi LM317 variants (LM317LBZRAG, LM317LZRAG, LM317LBZRPG, LM317LZG, LM317LZREG, LM317LZRMG, LM317LZRPG). All are active products with ROHS3 compliance. LM317LBZRAG and LM317LBZRPG offer extended operating temperature range (-40°C ~ 125°C) for applications requiring wider temperature performance.

For Automotive Applications: NCV317LBZRAG is the appropriate selection, offering AEC-Q100 qualification with extended temperature range (-40°C ~ 125°C) and automotive-grade reliability.

For Cross-Manufacturer Compatibility: LM317LCLPR and LM317LCLPRE3 from Texas Instruments are functionally compatible but carry Last Time Buy status. These parts have reduced maximum output voltage (32V vs 37V) and lower quiescent current (2.5mA vs 10mA). Use only when onsemi variants are unavailable and application voltage requirements do not exceed 32V output.

Compliance Considerations: All recommended substitutes maintain ROHS3 compliance and REACH Unaffected status, matching the original part's regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can LM317LBZRAG replace LM317LZX directly? A: Yes. LM317LBZRAG meets all electrical specifications of LM317LZX with identical voltage and current ratings. The primary difference is extended operating temperature range (-40°C vs 0°C minimum) and active product status, making it suitable for direct replacement.

Q: What is the difference between LM317LZRAG and LM317LBZRAG? A: Both parts are electrically identical with 40V input maximum, 1.2V to 37V output range, and 100mA output current. LM317LBZRAG operates from -40°C to 125°C, while LM317LZRAG operates from 0°C to 125°C. Select LM317LBZRAG for applications requiring extended low-temperature performance.

Q: Why are Texas Instruments LM317LCLPR and LM317LCLPRE3 listed as substitutes if they have different specifications? A: These parts are cross-manufacturer alternatives with the same base functionality and package. However, they have reduced maximum output voltage (32V vs 37V) and lower quiescent current (2.5mA vs 10mA). They are suitable only when application requirements do not exceed 32V output voltage and onsemi variants are unavailable.

Q: Is NCV317LBZRAG suitable for consumer applications? A: NCV317LBZRAG is automotive-grade with AEC-Q100 qualification. While it can be used in consumer applications, it is optimized for automotive environments. For standard consumer applications, standard LM317 variants are appropriate.

Q: What packaging differences exist between LM317LZX and its substitutes? A: LM317LZX uses TO-92-3 (TO-226AA) formed leads. Most onsemi substitutes use TO-92 (TO-226) long body formed leads, which are mechanically compatible with TO-92-3 footprints. Texas Instruments variants use TO-92-3 (TO-226AA) formed leads, matching the original package exactly.

Q: Are all substitutes ROHS3 compliant? A: All recommended active and last-time-buy substitutes are ROHS3 compliant. The original LM317LZX does not specify RoHS status due to its obsolete classification.

Q: Can I use LM317LZG in high-volume production? A: Yes. LM317LZG is an active product with 44,220 pieces in stock, making it suitable for high-volume applications. It meets all electrical specifications of LM317LZX with ROHS3 compliance.

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