LM317MBDT Equivalent & Substitute Parts

Part Overview

The LM317MBDT is a linear voltage regulator IC with positive adjustable output, rated for 500mA maximum output current in a DPAK surface mount package. Manufactured by onsemi, this component is classified as obsolete, which necessitates identification of active equivalent and substitute parts for ongoing design requirements and procurement planning.

The LM317MBDT provides adjustable output voltage regulation from 1.2V to 37V with integrated protection features including over-current, over-temperature, and short-circuit protection. Its 10mA quiescent current and 80dB to 65dB PSRR at 120Hz make it suitable for general-purpose linear regulation applications.

Key Parameters

Parameter	Value
Output Configuration	Positive
Output Type	Adjustable
Voltage - Input (Max)	40V
Voltage - Output (Min/Fixed)	1.2V
Voltage - Output (Max)	37V
Current - Output	500mA
Current - Quiescent (Iq)	10 mA
PSRR	80dB ~ 65dB (120Hz)
Protection Features	Over Current, Over Temperature, Short Circuit
Operating Temperature	-40°C ~ 125°C (TJ)
Package / Case	TO-252-3, DPAK (2 Leads + Tab), SC-63
Mounting Type	Surface Mount
RoHS Status	RoHS non-compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the LM317MBDT is determined by the following critical parameters:

Electrical Compatibility Requirements:

Output configuration: Positive adjustable
Maximum input voltage: 40V
Output voltage range: 1.2V to 37V minimum
Output current capability: 500mA minimum
Protection features: Over-current, over-temperature, short-circuit
Operating temperature range: -40°C to 125°C minimum

Mechanical Compatibility Requirements:

Package type: TO-252-3 / DPAK (2 Leads + Tab) / SC-63
Mounting type: Surface mount
Pin configuration: Compatible with DPAK footprint

Substitute parts are grouped into two categories:

Direct Manufacturer Equivalents (onsemi): Parts with identical electrical specifications and packaging from the original manufacturer, differing only in product status (active vs. obsolete) and RoHS compliance.

Cross-Manufacturer Equivalents: Parts from Texas Instruments and STMicroelectronics with matching or superior electrical specifications and identical packaging, enabling direct PCB substitution.

Higher Current Variants: Texas Instruments LM317AMDT/NOPB and LM317AMDTX/NOPB provide 1.5A output current capability while maintaining all other electrical and mechanical compatibility parameters.

Parameter Comparison

Part Number	Manufacturer	Product Status	Output Current	Voltage - Input (Max)	Voltage - Output (Min)	Voltage - Output (Max)	Operating Temp	RoHS Status	Package	Inventory
LM317MBDT	onsemi	Obsolete	500mA	40V	1.2V	37V	-40°C ~ 125°C	RoHS non-compliant	DPAK	5200 Pcs
LM317MBDTG	onsemi	Active	500mA	40V	1.2V	37V	-40°C ~ 125°C	ROHS3 Compliant	DPAK	485300 Pcs
LM317MABDTG	onsemi	Active	500mA	40V	1.2V	37V	-40°C ~ 125°C	ROHS3 Compliant	DPAK	2502 Pcs
LM317MKVURG3	Texas Instruments	Active	500mA	40V	1.25V	37V	-40°C ~ 125°C	ROHS3 Compliant	TO-252-3	5700 Pcs
LM217MDT-TR	STMicroelectronics	Active	500mA	40V	1.2V	37V	-40°C ~ 125°C	ROHS3 Compliant	DPAK	146942 Pcs
LM317AMDT/NOPB	Texas Instruments	Active	1.5A	40V	1.25V	37V	-40°C ~ 125°C	ROHS3 Compliant	TO-252-3	4699 Pcs
LM317AMDTX/NOPB	Texas Instruments	Active	1.5A	40V	1.25V	37V	-40°C ~ 125°C	ROHS3 Compliant	TO-252-3	1900 Pcs
LM317MDT-TR	STMicroelectronics	Active	500mA	40V	1.2V	37V	0°C ~ 125°C	ROHS3 Compliant	DPAK	150200 Pcs
LM317MDT/NOPB	Texas Instruments	Active	500mA	37V	1.25V	37V	0°C ~ 125°C	ROHS3 Compliant	TO-252-3	2901 Pcs
LM317MDTX/NOPB	Texas Instruments	Active	500mA	37V	1.25V	37V	0°C ~ 125°C	ROHS3 Compliant	TO-252-3	2200 Pcs

Engineering Selection Recommendations

Primary Recommendation - Direct onsemi Equivalent: LM317MBDTG is the direct active equivalent from onsemi with identical electrical specifications and DPAK packaging. This part maintains full compatibility with existing PCB designs and offers the highest inventory availability (485,300 pcs). The transition from RoHS non-compliant to ROHS3 compliant status aligns with current regulatory requirements.

Secondary Recommendation - onsemi Alternative: LM317MABDTG provides identical electrical and mechanical specifications with ROHS3 compliance. Lower inventory levels (2,502 pcs) may impact lead times for high-volume requirements.

Cross-Manufacturer Equivalents - Texas Instruments: LM317MKVURG3 maintains 500mA output current with 40V maximum input voltage and ROHS3 compliance. Minimum output voltage specification of 1.25V (versus 1.2V) represents a minor deviation. MSL rating of 3 (168 hours) requires moisture control during storage and handling compared to MSL 1 for onsemi parts.

LM317AMDT/NOPB and LM317AMDTX/NOPB provide enhanced 1.5A output current capability, suitable for applications requiring higher current delivery while maintaining all voltage and temperature specifications. These parts are appropriate for designs where current headroom is beneficial.

LM317MDT/NOPB and LM317MDTX/NOPB offer 500mA output current with reduced maximum input voltage specification (37V versus 40V). Operating temperature range begins at 0°C rather than -40°C. These specifications remain suitable for applications within these constraints.

Cross-Manufacturer Equivalent - STMicroelectronics: LM217MDT-TR and LM317MDT-TR provide 500mA output current with full 40V input voltage capability and ROHS3 compliance. LM217MDT-TR maintains -40°C to 125°C operating range identical to the original part. LM317MDT-TR specifies 0°C minimum operating temperature. Both parts offer high inventory availability (146,942 and 150,200 pcs respectively).

Frequently Asked Questions (FAQ)

Q: Can LM317MBDTG be used as a direct replacement for LM317MBDT?

A: Yes. LM317MBDTG is the active equivalent from onsemi with identical electrical specifications (500mA output, 1.2V to 37V adjustable output, 40V maximum input), identical DPAK packaging, and matching operating temperature range (-40°C to 125°C). The primary difference is product status (active versus obsolete) and RoHS compliance (ROHS3 versus non-compliant).

Q: What is the difference between LM317MBDTG and LM317MABDTG?

A: Both parts are onsemi products with identical electrical specifications and DPAK packaging. The primary distinction is inventory availability: LM317MBDTG has 485,300 pcs in stock versus 2,502 pcs for LM317MABDTG. Both are ROHS3 compliant and active products.

Q: Can Texas Instruments LM317AMDT/NOPB replace the LM317MBDT?

A: Yes, with design considerations. LM317AMDT/NOPB provides 1.5A output current (versus 500mA), maintaining all voltage specifications (1.25V to 37V adjustable output, 40V maximum input) and operating temperature range (-40°C to 125°C). The higher current rating makes this part suitable for applications requiring additional current capacity. Minimum output voltage is 1.25V rather than 1.2V, which is acceptable for most applications.

Q: What is the significance of the MSL (Moisture Sensitivity Level) difference?

A: LM317MBDT and most onsemi/STMicroelectronics equivalents specify MSL 1 (unlimited moisture exposure tolerance). Texas Instruments LM317MKVURG3 specifies MSL 3 (168 hours maximum exposure at 60% relative humidity and 30°C before reflow). MSL 3 parts require controlled storage conditions and moisture bake-out procedures before soldering. For applications with standard manufacturing processes and storage conditions, MSL 1 parts are preferred.

Q: Are there output voltage specification differences between substitutes?

A: Minor variations exist. LM317MBDT specifies minimum output voltage of 1.2V. Texas Instruments parts (LM317MKVURG3, LM317AMDT/NOPB, LM317AMDTX/NOPB, LM317MDT/NOPB, LM317MDTX/NOPB) specify 1.25V minimum. STMicroelectronics LM217MDT-TR and LM317MDT-TR specify 1.2V minimum. These differences are negligible for most adjustable regulator applications where output voltage is set via external resistor dividers.

Q: Which substitute offers the best inventory availability?

A: LM317MBDTG from onsemi offers the highest inventory with 485,300 pcs in stock, followed by LM317MDT-TR from STMicroelectronics (150,200 pcs) and LM217MDT-TR from STMicroelectronics (146,942 pcs).

Q: Can I use LM317MDT/NOPB if my application requires -40°C operation?

A: No. LM317MDT/NOPB specifies 0°C to 125°C operating temperature range, which does not include -40°C. For applications requiring -40°C operation, use LM317MBDTG, LM317MABDTG, LM217MDT-TR, or LM317MKVURG3, all of which specify -40°C minimum operating temperature.

Q: What is the maximum input voltage difference between substitutes?

A: LM317MBDT specifies 40V maximum input voltage. Most equivalents maintain this specification. Texas Instruments LM317MDT/NOPB and LM317MDTX/NOPB specify 37V maximum input voltage. For applications requiring 40V input capability, avoid these two parts.

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