LM317MDTX Equivalent & Substitute Parts

Part Overview

The LM317MDTX is a linear voltage regulator IC from onsemi, configured for positive adjustable output at 500mA in DPAK packaging. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The LM317 series 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	onsemi
Category	Power Management (PMIC)
Output Configuration	Positive
Output Type	Adjustable
Number of Regulators	1
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	1.2V
Voltage - Output (Max)	37V
Current - Output	500mA
Current - Quiescent (Iq)	10 mA
PSRR	80dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit
Operating Temperature	0°C ~ 125°C (TJ)
Mounting Type	Surface Mount
Package / Case	TO-252-3, DPAK (2 Leads + Tab), SC-63
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the LM317MDTX is determined by the following critical parameters:

Output voltage range: 1.2V to 37V adjustable
Output current capability: 500mA
Package type: TO-252-3 DPAK (2 Leads + Tab)
Protection features: Over-current, over-temperature, short-circuit
Input voltage maximum: 40V
Quiescent current: 10mA
PSRR: 80dB at 120Hz

Substitute parts are grouped into three categories: direct manufacturer equivalents from onsemi with different packaging configurations, cross-manufacturer alternatives from Texas Instruments and STMicroelectronics with identical electrical specifications, and automotive-grade variants with AEC-Q100 qualification. All substitutes maintain the same DPAK package footprint and electrical performance envelope.

Parameter Comparison

Part Number	Manufacturer	Packaging	Product Status	Voltage Input (Max)	Voltage Output Min/Max	Current Output	Operating Temp	RoHS Status
LM317MDTX	onsemi	DPAK	Obsolete	40V	1.2V / 37V	500mA	0°C ~ 125°C	Not specified
LM317MADTRKG	onsemi	Tape & Reel (TR)	Active	40V	1.2V / 37V	500mA	0°C ~ 125°C	ROHS3 Compliant
LM317MABDTG	onsemi	Tube	Active	40V	1.2V / 37V	500mA	-40°C ~ 125°C	ROHS3 Compliant
LM317MABDTRKG	onsemi	Cut Tape (CT) & Digi-Reel®	Active	40V	1.2V / 37V	500mA	-40°C ~ 125°C	ROHS3 Compliant
LM317MBDTG	onsemi	Tube	Active	40V	1.2V / 37V	500mA	-40°C ~ 125°C	ROHS3 Compliant
LM317MBDTRKG	onsemi	Cut Tape (CT) & Digi-Reel®	Active	40V	1.2V / 37V	500mA	-40°C ~ 125°C	ROHS3 Compliant
LM317MDTG	onsemi	Tube	Active	40V	1.2V / 37V	500mA	0°C ~ 125°C	ROHS3 Compliant
LM317MDTRKG	onsemi	Cut Tape (CT) & Digi-Reel®	Active	40V	1.2V / 37V	500mA	0°C ~ 125°C	ROHS3 Compliant
NCV317MBDTRKG	onsemi	Tape & Reel (TR)	Active	40V	1.2V / 37V	500mA	-40°C ~ 125°C	ROHS3 Compliant
LM317MKVURG3	Texas Instruments	Cut Tape (CT) & Digi-Reel®	Active	40V	1.25V / 37V	500mA	-40°C ~ 125°C	ROHS3 Compliant
LM217MDT-TR	STMicroelectronics	Cut Tape (CT) & Digi-Reel®	Active	40V	1.2V / 37V	500mA	-40°C ~ 125°C	ROHS3 Compliant

Engineering Selection Recommendations

For direct replacement of the obsolete LM317MDTX, select from active onsemi LM317 variants with matching temperature range (0°C ~ 125°C): LM317MADTRKG, LM317MDTG, or LM317MDTRKG. These maintain identical electrical specifications and DPAK packaging.

For extended temperature operation (-40°C ~ 125°C), onsemi offers LM317MABDTG, LM317MABDTRKG, LM317MBDTG, and LM317MBDTRKG. All onsemi variants are ROHS3 compliant and carry unlimited moisture sensitivity rating (MSL 1).

Cross-manufacturer alternatives include the Texas Instruments LM317MKVURG3 and STMicroelectronics LM217MDT-TR, both active and ROHS3 compliant. The Texas Instruments part specifies 1.25V minimum output voltage versus 1.2V for onsemi variants. The STMicroelectronics LM217 omits over-current protection compared to the LM317 series.

For automotive applications requiring AEC-Q100 qualification, the onsemi NCV317MBDTRKG provides equivalent electrical performance with automotive-grade certification.

Packaging selection depends on procurement requirements: Tape & Reel (TR) for high-volume automated assembly, Cut Tape (CT) & Digi-Reel® for mixed-volume orders, or Tube for lower-volume manual placement.

Frequently Asked Questions (FAQ)

Q: Can LM317MDTX be directly replaced with LM317MADTRKG?

A: Yes. Both parts share identical electrical specifications, DPAK package footprint, and operating temperature range (0°C ~ 125°C). The difference is packaging: LM317MADTRKG uses Tape & Reel format versus the original DPAK. Electrical performance and PCB layout compatibility are equivalent.

Q: What is the difference between onsemi LM317 variants with different letter codes (MA, MB, MD)?

A: The letter codes indicate manufacturing date codes and internal process revisions. All variants maintain the same electrical specifications and DPAK package. Selection should be based on operating temperature requirements and packaging format availability.

Q: Is the Texas Instruments LM317MKVURG3 a suitable replacement?

A: Yes, with one specification difference: minimum output voltage is 1.25V versus 1.2V for onsemi parts. This is acceptable for most applications requiring adjustable regulation above 1.25V. Moisture sensitivity is MSL 3 (168 hours) versus MSL 1 for onsemi variants.

Q: Why does the STMicroelectronics LM217MDT-TR lack over-current protection?

A: The LM217 series is a lower-cost variant of the LM317 family with reduced protection features. It provides over-temperature and short-circuit protection but not over-current protection. Select LM217 only if over-current protection is not required by the application.

Q: What packaging format should be selected for production?

A: Tape & Reel (TR) is standard for automated pick-and-place assembly at high volumes. Cut Tape (CT) & Digi-Reel® accommodates mixed-volume orders with reduced tape waste. Tube packaging is suitable for manual assembly or low-volume prototyping.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. The original LM317MDTX does not specify RoHS status due to its obsolete classification.

Q: Can the NCV317MBDTRKG be used in non-automotive applications?

A: Yes. The NCV317MBDTRKG is an automotive-grade variant with AEC-Q100 qualification, but it functions identically to standard LM317 parts in non-automotive circuits. It provides extended temperature range (-40°C ~ 125°C) and higher reliability margins.

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