LMX331AXK-T Equivalent & Substitute Parts

Part Overview

The LMX331AXK-T is a general-purpose comparator IC manufactured by Analog Devices Inc./Maxim Integrated, housed in a 5-TSSOP (SC-70-5) surface-mount package. This device features open-drain output configuration and operates across a supply voltage range of 1.8V to 5.5V, making it suitable for low-power analog signal comparison applications. The part is currently classified as obsolete, necessitating identification of active equivalent alternatives that maintain functional and electrical compatibility for ongoing production and maintenance requirements.

Substiute Parts

LMX331AXK-T

Analog Devices Inc./Maxim IntegratedIn Stock: 1049LMX331AXK-T Datasheet

Current PartRFQ

MAX9647AXK+T

Analog Devices Inc./Maxim IntegratedIn Stock: 3003MAX9647AXK+T Datasheet

DirectRFQ

LMV331ICT

STMicroelectronicsIn Stock: 1766LMV331ICT Datasheet

MFR RecommendedRFQ

LMV331IDCKR

Texas InstrumentsIn Stock: 65451LMV331IDCKR Datasheet

MFR RecommendedRFQ

LMV331M7/NOPB

Texas InstrumentsIn Stock: 2465LMV331M7/NOPB Datasheet

MFR RecommendedRFQ

LMV331SN3T1G

onsemiIn Stock: 40196LMV331SN3T1G Datasheet

MFR RecommendedRFQ

NCV331SN3T1G

onsemiIn Stock: 65369NCV331SN3T1G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LMX331AXK-T is determined by the following critical parameters:

Primary Compatibility Criteria:

• Package type: 5-TSSOP / SC-70-5 / SOT-353 (surface-mount, pin-compatible)
• Functional classification: General-purpose comparator with single element
• Output configuration: Open-drain or functionally equivalent output type
• Supply voltage range: Must encompass or overlap with 1.8V ~ 5.5V
• Input offset voltage: Maximum 7mV @ 5V
• Input bias current: Maximum 0.25µA @ 5V
• Operating temperature range: Minimum -40°C to +125°C coverage

Secondary Compatibility Considerations:

• Propagation delay: Maximum 600ns
• Quiescent current: Maximum 120µA
• Hysteresis: 2mV specification

Substitute parts are grouped based on their adherence to these electrical and mechanical parameters. Parts meeting all primary criteria are considered direct functional equivalents. Variations in secondary parameters (such as PSRR, output current capability, or propagation delay) do not preclude substitution when primary criteria are satisfied, as these represent performance enhancements or trade-offs acceptable within general-purpose comparator applications.

Parameter Comparison

Engineering Selection Recommendations

MAX9647AXK+T (Analog Devices Inc./Maxim Integrated) Direct manufacturer alternative with active product status. Maintains identical supply voltage range (1.8V ~ 5.5V) and operating temperature coverage (-40°C ~ 125°C). Offers improved propagation delay (110ns versus 600ns) and enhanced PSRR (90dB versus 70dB). ROHS3 compliant. Recommended as primary replacement for new designs and production continuity.

LMV331ICT (STMicroelectronics) Active product with open-drain output configuration. Supply voltage range reduced to 2.7V ~ 5V; operating temperature limited to -40°C ~ 85°C. Propagation delay (550ns) and output current (93mA) closely match original specifications. ROHS3 compliant. Suitable for applications not requiring 1.8V minimum supply or extended temperature range above 85°C.

LMV331IDCKR (Texas Instruments) Active product with open-collector output (functionally equivalent to open-drain in most applications). Supply voltage range 2.7V ~ 5.5V; operating temperature -40°C ~ 85°C. Propagation delay and output current specifications align with original device. ROHS3 compliant. Acceptable substitute where open-collector output is compatible with circuit design.

LMV331M7/NOPB (Texas Instruments) Active product offering multi-output configuration (CMOS, Open-Collector, TTL). Supply voltage 2.7V ~ 5.5V; operating temperature -40°C ~ 85°C. Propagation delay and quiescent current match original specifications. ROHS3 compliant. Provides enhanced output flexibility for diverse circuit topologies.

LMV331SN3T1G (onsemi) Active product with open-drain output. Supply voltage 2.7V ~ 5V; operating temperature range not specified in data. Input bias current significantly reduced (0.001µA versus 0.25µA). Propagation delay extended to 1.5µs. Package designation SOT-23-5 Thin (TSOT-23-5) differs from original SC-70-5. ROHS3 compliant. Substitution requires PCB layout verification for package compatibility.

NCV331SN3T1G (onsemi) Active product with automotive-grade qualification (AEC-Q100). Open-drain output configuration. Supply voltage 2.7V ~ 5V; operating temperature -40°C ~ 85°C. Input bias current 0.001µA; propagation delay 800ns. Package SOT-23-5 Thin (TSOT-23-5). ROHS3 compliant. Suitable for automotive applications requiring AEC-Q100 certification; PCB layout verification required for package transition.

Frequently Asked Questions (FAQ)

Q: Can MAX9647AXK+T directly replace LMX331AXK-T without circuit modification? A: Yes. MAX9647AXK+T maintains identical package (5-TSSOP, SC-70-5), supply voltage range (1.8V ~ 5.5V), operating temperature range (-40°C ~ 125°C), and open-drain output configuration. Pin-for-pin compatibility is confirmed. No circuit modifications are required.

Q: Why do some substitutes have reduced operating temperature range (-40°C ~ 85°C versus -40°C ~ 125°C)? A: LMV331ICT, LMV331IDCKR, and LMV331M7/NOPB are rated to 85°C maximum junction temperature, limiting upper operating temperature to 85°C. Applications requiring operation above 85°C must use MAX9647AXK+T or verify thermal management capability within the substitute device's specified range.

Q: What is the functional difference between open-drain and open-collector outputs? A: Both output configurations require external pull-up resistors and are functionally equivalent in most comparator applications. Open-drain uses NMOS transistor output; open-collector uses BJT output. Circuit behavior is identical when properly terminated. LMV331IDCKR (open-collector) and LMV331M7/NOPB (multi-output including open-collector) are compatible substitutes.

Q: Are LMV331SN3T1G and NCV331SN3T1G pin-compatible with the original LMX331AXK-T? A: No. These devices use SOT-23-5 Thin (TSOT-23-5) package instead of SC-70-5. While pin count is identical (5 pins), physical package dimensions and PCB footprint differ. PCB layout redesign is required for substitution.

Q: Which substitute offers the best performance improvement? A: MAX9647AXK+T provides the most significant performance enhancement with propagation delay reduced from 600ns to 110ns and PSRR improved from 70dB to 90dB, while maintaining full compatibility with the original device specifications.

Q: Are all substitutes RoHS compliant? A: All listed substitutes are ROHS3 compliant. The original LMX331AXK-T is RoHS non-compliant. Substitution to any listed alternative satisfies RoHS compliance requirements for new production.

Q: What is the inventory status for each substitute? A: MAX9647AXK+T: 2,971 pcs; LMV331ICT: 1,688 pcs; LMV331IDCKR: 65,400 pcs; LMV331M7/NOPB: 2,400 pcs; LMV331SN3T1G: 40,100 pcs; NCV331SN3T1G: 65,300 pcs. Availability varies; verify current stock with supplier before design commitment.

Q: Can NCV331SN3T1G be used in non-automotive applications? A: Yes. NCV331SN3T1G meets all electrical specifications for general-purpose comparator applications. AEC-Q100 automotive qualification is an additional certification; the device functions identically in non-automotive circuits. Substitution is valid regardless of application classification.