LM397MFX Equivalent & Substitute Parts

Part Overview

The LM397MFX is a general-purpose comparator IC manufactured by Texas Instruments, featuring open-collector, rail-to-rail output in a SOT-23-5 surface mount package. The device operates across a wide supply voltage range (5V ~ 30V single supply, ±2.5V ~ 15V dual supply) and is designed for precision voltage comparison applications in industrial and consumer electronics.

The LM397MFX carries an Obsolete product status. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support long-term production requirements for applications currently using this comparator.

Substiute Parts

LM397MFX

Texas InstrumentsIn Stock: 26492LM397MFX Datasheet

Current PartRFQ

LM397MF

Texas InstrumentsIn Stock: 1772LM397MF Datasheet

Parametric EquivalentRFQ

LM397MF/NOPB

Texas InstrumentsIn Stock: 20498LM397MF/NOPB Datasheet

Parametric EquivalentRFQ

LM397MFX/NOPB

Texas InstrumentsIn Stock: 35335LM397MFX/NOPB Datasheet

Parametric EquivalentRFQ

MIC6270YM5-TR

Microchip TechnologyIn Stock: 22911MIC6270YM5-TR Datasheet

MFR RecommendedRFQ

TA75S393F,LF

Toshiba Semiconductor and StorageIn Stock: 150414TA75S393F,LF Datasheet

MFR RecommendedRFQ

TS391RILT

STMicroelectronicsIn Stock: 17129TS391RILT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LM397MFX are classified based on strict electrical and mechanical compatibility criteria:

Primary Substitution Criteria:

• Package / Case: SC-74A, SOT-753 (physical and pin compatibility)
• Supplier Device Package: SOT-23-5 (footprint compatibility)
• Mounting Type: Surface Mount
• Type: General Purpose Comparator
• Number of Elements: 1
• Output Type: Open-Collector capability (required for direct pin-level compatibility)
• Voltage - Supply Range: Must support 5V ~ 30V single supply minimum
• Operating Temperature: -40°C ~ 85°C minimum range
• Current - Input Bias (Max): 0.25µA @ 5V or lower
• Current - Output (Typ): 13mA @ 5V or higher

Substitutes are grouped into two categories:

Category 1: Parametric Equivalents (Texas Instruments LM397 Series) Parts that maintain identical electrical specifications and are from the same manufacturer base product line. These include LM397MF, LM397MF/NOPB, and LM397MFX/NOPB, differing only in packaging format and product status.

Category 2: Manufacturer-Recommended Alternatives Parts from alternative manufacturers (Microchip Technology, Toshiba Semiconductor, STMicroelectronics) that meet or exceed the electrical performance requirements while maintaining mechanical compatibility through identical package specifications.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications): LM397MF/NOPB and LM397MFX/NOPB are the primary choices. Both maintain identical electrical parameters to the LM397MFX while offering Active product status and ROHS3 compliance. LM397MF/NOPB is available in higher inventory (20,400 pcs) with Cut Tape and Digi-Reel packaging options. LM397MFX/NOPB provides the highest inventory availability (35,300 pcs) with identical specifications.

For Extended Supply Voltage Range: MIC6270YM5-TR (Microchip Technology) and TS391RILT (STMicroelectronics) support expanded supply voltage ranges (2V ~ 36V single supply, ±1V ~ 18V dual supply) compared to the LM397MFX (5V ~ 30V, ±2.5V ~ 15V). Both are ROHS3 compliant and Active status. MIC6270YM5-TR offers improved input offset voltage (5mV @ 5V) and higher output current (20mA @ 5V). TS391RILT extends operating temperature to -40°C ~ 125°C.

For Lowest Quiescent Current: TA75S393F,LF (Toshiba Semiconductor) provides the lowest quiescent current (800µA) and lowest input bias current (0.05µA @ 5V), beneficial for battery-powered or low-power applications. This part is available in highest inventory (150,404 pcs) and is ROHS3 compliant with Active status. Note: Supplier Device Package is SMV rather than SOT-23-5.

For Compliance and Supply Chain Continuity: All substitute parts carry ROHS3 compliance and Active product status, ensuring long-term availability and regulatory alignment. LM397MF/NOPB and LM397MFX/NOPB are recommended for designs requiring identical electrical performance with modern compliance certifications.

Frequently Asked Questions (FAQ)

Q: Can I directly replace LM397MFX with LM397MF/NOPB? A: Yes. Both parts share identical electrical specifications, package type (SC-74A, SOT-753), and SOT-23-5 footprint. The primary differences are product status (LM397MFX is Obsolete; LM397MF/NOPB is Active) and RoHS compliance (LM397MFX is non-compliant; LM397MF/NOPB is ROHS3 compliant). No circuit modifications are required.

Q: What is the difference between LM397MF and LM397MF/NOPB? A: Both parts are electrically identical. The "/NOPB" designation indicates the part is supplied in Cut Tape and Digi-Reel packaging formats with no lead (Pb) content. LM397MF is supplied in Cut Tape format only. Select based on packaging and handling requirements for your production process.

Q: Can I use MIC6270YM5-TR as a substitute if my circuit operates at 2V supply voltage? A: Yes. MIC6270YM5-TR supports supply voltages from 2V ~ 36V (single supply) and ±1V ~ 18V (dual supply), which exceeds the LM397MFX minimum of 5V. The part is pin-compatible in the same SOT-23-5 package. Verify that your circuit design does not depend on the specific input offset voltage or output current characteristics of the LM397MFX.

Q: Why does TA75S393F,LF show a different Supplier Device Package (SMV) instead of SOT-23-5? A: TA75S393F,LF uses the SMV package designation, which is a Toshiba-specific designation for a surface mount package equivalent to SOT-23-5 in physical dimensions and pin configuration. The Package / Case specification (SC-74A, SOT-753) confirms mechanical compatibility. Verify PCB footprint compatibility with your design before implementation.

Q: Which substitute part offers the best performance for low-power applications? A: TA75S393F,LF provides the lowest quiescent current (800µA) and input bias current (0.05µA @ 5V), making it optimal for battery-powered or energy-constrained designs. However, confirm that the SMV package designation aligns with your PCB layout and manufacturing capabilities.

Q: Are all substitute parts RoHS compliant? A: Yes. All substitute parts listed (LM397MF, LM397MF/NOPB, LM397MFX/NOPB, MIC6270YM5-TR, TA75S393F,LF, and TS391RILT) are ROHS3 compliant. The original LM397MFX is RoHS non-compliant. Substitution ensures regulatory compliance for new production runs.

Q: Can I use TS391RILT in applications requiring operation above 85°C? A: TS391RILT supports operating temperatures from -40°C ~ 125°C, extending the upper temperature limit by 40°C compared to the LM397MFX (-40°C ~ 85°C). This makes it suitable for high-temperature industrial applications. Verify that all other electrical parameters meet your circuit requirements.

Q: What inventory considerations should I account for when selecting a substitute? A: LM397MFX/NOPB offers the highest inventory (35,300 pcs), followed by TA75S393F,LF (150,404 pcs). For immediate availability and long-term supply security, LM397MFX/NOPB is recommended. TA75S393F,LF provides exceptional inventory depth if the SMV package is compatible with your manufacturing process.