LM311MX Equivalent & Substitute Parts

Part Overview

The LM311MX is a general-purpose voltage comparator manufactured by Texas Instruments in 8-SOIC surface-mount packaging. This device features open-collector and open-emitter outputs suitable for DTL, MOS, RTL, and TTL logic interfacing. The LM311MX is classified as Last Time Buy, indicating end-of-life status from the original manufacturer. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support long-term production requirements.

Substiute Parts

LM311MX

Texas InstrumentsIn Stock: 12457LM311MX Datasheet

Current PartRFQ

LM311MX/NOPB

Texas InstrumentsIn Stock: 23369LM311MX/NOPB Datasheet

DirectRFQ

LM211DR2G

onsemiIn Stock: 16142LM211DR2G Datasheet

MFR RecommendedRFQ

LM211DT

STMicroelectronicsIn Stock: 46505LM211DT Datasheet

MFR RecommendedRFQ

LM311D

National SemiconductorIn Stock: 2157LM311D Datasheet

MFR RecommendedRFQ

LM311DR2G

onsemiIn Stock: 516974LM311DR2G Datasheet

MFR RecommendedRFQ

LM311DT

STMicroelectronicsIn Stock: 59659LM311DT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM311MX is determined by the following critical parameters:

Mandatory Compatibility Criteria:

• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Mounting Type: Surface Mount
• Type: General Purpose Comparator
• Number of Elements: 1
• Output Type: Must include Open-Collector and/or Open-Emitter capability
• Voltage - Supply, Single/Dual (±): Must support 5V ~ 30V and ±2.5V ~ 15V minimum
• Voltage - Input Offset (Max): 7.5mV @ 15V or better
• Current - Input Bias (Max): 0.25µA @ ±15V or better
• Current - Quiescent (Max): 7.5mA or lower

Acceptable Parameter Variations:

• Operating Temperature range may extend beyond 0°C ~ 70°C
• Current - Output (Typ) may be specified or unspecified
• RoHS and REACH compliance status may differ
• Product Status may be Active (preferred) or Obsolete (acceptable with inventory availability)

Substitute parts meeting these criteria are functionally interchangeable in applications designed for the LM311MX.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute (Highest Compatibility): LM311DR2G (onsemi) and LM311DT (STMicroelectronics) are direct functional equivalents to the LM311MX. Both maintain identical electrical specifications, 8-SOIC packaging, and ROHS3 compliance. LM311DR2G offers the largest available inventory (516,900 units), providing superior supply chain security. LM311DT supports extended operating temperature range (-40°C ~ 105°C) and specified output current (50mA), making it suitable for applications requiring broader thermal performance.

Secondary Substitute (Improved Performance): LM211DR2G (onsemi) and LM211DT (STMicroelectronics) offer superior electrical characteristics with reduced input offset voltage (3mV vs. 7.5mV) and input bias current (0.1µA vs. 0.25µA). LM211DT extends operating temperature to -40°C ~ 105°C. These parts are functionally compatible but represent performance enhancements rather than direct replacements.

Alternative (Limited Availability): LM311MX/NOPB (Texas Instruments) is the NOPB variant of the original part with expanded supply voltage range (5V ~ 36V, ±2.5V ~ 18V). This part maintains Last Time Buy status but offers 23,305 units in inventory.

Not Recommended: LM311D (National Semiconductor) is obsolete with limited inventory (2,100 units) and RoHS non-compliance. Use only when no other alternatives are available and RoHS compliance is not required.

Frequently Asked Questions (FAQ)

Q: Can LM311DR2G replace LM311MX directly? A: Yes. LM311DR2G maintains identical electrical specifications, package type (8-SOIC), and operating temperature range (0°C ~ 70°C) as the LM311MX. Both are ROHS3 compliant. The primary difference is manufacturer (onsemi vs. Texas Instruments) and significantly higher inventory availability.

Q: What is the difference between LM311 and LM211 series comparators? A: Both are general-purpose voltage comparators in 8-SOIC packaging with compatible pinouts. LM211 devices feature improved electrical performance: input offset voltage of 3mV (vs. 7.5mV) and input bias current of 0.1µA (vs. 0.25µA). LM211DT supports extended operating temperature (-40°C ~ 105°C vs. 0°C ~ 70°C). Selection depends on application precision requirements and thermal environment.

Q: Is LM311MX/NOPB a suitable substitute? A: Yes, with qualification. LM311MX/NOPB is the NOPB (No Plumbum/Lead-Free) variant from Texas Instruments with expanded supply voltage range (5V ~ 36V, ±2.5V ~ 18V). It maintains ROHS3 compliance and identical performance characteristics. Use when extended supply voltage range is beneficial or when maintaining original manufacturer sourcing is required.

Q: Why is LM311D not recommended? A: LM311D is classified as Obsolete with only 2,100 units available. It is RoHS non-compliant, which may violate procurement standards for new designs. Use only in legacy applications where RoHS compliance is not mandated and inventory is confirmed available.

Q: Can I use LM211DT in place of LM311MX? A: Yes. LM211DT is functionally compatible and offers superior electrical performance (lower input offset voltage and bias current). The extended operating temperature range (-40°C ~ 105°C) provides additional thermal margin. Verify that improved performance characteristics do not introduce unintended circuit behavior in existing designs.

Q: What packaging options are available for these comparators? A: All listed substitute parts are available in 8-SOIC surface-mount packaging (0.154", 3.90mm width). Packaging is consistent across all alternatives, ensuring PCB layout compatibility without redesign.

Q: Are there RoHS compliance concerns with any substitute? A: LM311D is RoHS non-compliant. All other substitutes (LM311MX/NOPB, LM211DR2G, LM211DT, LM311DR2G, LM311DT) are ROHS3 compliant. Verify RoHS requirements for your application before part selection.