LM311M/NOPB Equivalent & Substitute Parts

Part Overview

The LM311M/NOPB is a general-purpose comparator IC manufactured by Texas Instruments in 8-SOIC surface mount packaging. This device operates across a wide supply voltage range (5V ~ 36V single supply, ±2.5V ~ 18V dual supply) and features open-collector, open-emitter, and TTL-compatible output configurations. The part is currently active in production with ROHS3 compliance and unlimited moisture sensitivity rating. Equivalent and substitute parts are necessary when the primary part experiences supply constraints, when alternative manufacturers' versions offer improved specifications, or when design requirements demand extended operating temperature ranges or enhanced electrical performance.

Key Parameters

Parameter	LM311M/NOPB
Manufacturer	Texas Instruments
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Active
Type	General Purpose Comparator
Number of Elements	1
Output Type	DTL, MOS, Open-Collector, Open-Emitter, RTL, TTL
Voltage - Supply, Single/Dual (±)	5V ~ 36V, ±2.5V ~ 18V
Voltage - Input Offset (Max)	7.5mV @ ±15V
Current - Input Bias (Max)	0.25µA @ ±15V
Current - Quiescent (Max)	7.5mA
Operating Temperature	0°C ~ 70°C
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the LM311M/NOPB is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Package / Case: 8-SOIC (0.154", 3.90mm Width)
Mounting Type: Surface Mount
Number of Elements: 1
Output Type: Must include Open-Collector and/or Open-Emitter capability
Voltage - Supply, Single/Dual (±): Must support minimum 5V ~ 36V single supply and ±2.5V ~ 18V dual supply ranges
Voltage - Input Offset (Max): Must not exceed 7.5mV @ ±15V
Current - Input Bias (Max): Must not exceed 0.25µA @ ±15V
Current - Quiescent (Max): Must not exceed 7.5mA

Acceptable Variations:

Operating Temperature range may extend beyond 0°C ~ 70°C
Current - Output (Typ) may be specified or unspecified
RoHS compliance status may differ
Manufacturer may differ
Product Status may be Active or Obsolete

The following parts meet these substitution criteria:

Direct Substitutes (Identical Base Specifications):

LM311D (National Semiconductor) — Obsolete status
LM311DR2G (onsemi) — Active status
LM311DT (STMicroelectronics) — Active status

Manufacturer-Recommended Alternatives (Enhanced Specifications):

LM211DR2G (onsemi) — Improved input offset voltage (3mV vs 7.5mV), extended operating temperature (-25°C ~ 85°C)
LM211DT (STMicroelectronics) — Improved input offset voltage (3mV vs 7.5mV), extended operating temperature (-40°C ~ 105°C), specified output current (50mA)
LT1011CS8#PBF (Analog Devices Inc.) — Superior input offset voltage (2mV), lower input bias current (0.065µA), lower quiescent current (4mA), extended supply voltage range (3V ~ 36V), specified CMRR (115dB)

Parameter Comparison

Parameter	LM311M/NOPB (TI)	LM311D (NSM)	LM311DR2G (onsemi)	LM311DT (STM)	LM211DR2G (onsemi)	LM211DT (STM)	LT1011CS8#PBF (ADI)
Manufacturer	Texas Instruments	National Semiconductor	onsemi	STMicroelectronics	onsemi	STMicroelectronics	Analog Devices Inc.
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Product Status	Active	Obsolete	Active	Active	Active	Active	Active
Voltage - Supply, Single/Dual (±)	5V ~ 36V, ±2.5V ~ 18V	4.6V ~ 30V, ±1.75V ~ 15V	5V ~ 30V, ±2.5V ~ 15V	5V ~ 30V, ±2.5V ~ 15V	5V ~ 30V, ±2.5V ~ 15V	5V ~ 30V, ±2.5V ~ 15V	3V ~ 36V, ±1.5V ~ 18V
Voltage - Input Offset (Max)	7.5mV @ ±15V	7.5mV @ ±15V	7.5mV @ ±15V	7.5mV @ ±15V	3mV @ ±15V	3mV @ ±15V	2mV @ ±15V
Current - Input Bias (Max)	0.25µA @ ±15V	0.25µA @ ±15V	0.25µA @ ±15V	0.25µA @ ±15V	0.1µA @ ±15V	0.1µA @ ±15V	0.065µA @ ±15V
Current - Output (Typ)	—	—	—	50mA	—	50mA	50mA
Current - Quiescent (Max)	7.5mA	7.5mA	7.5mA	7.5mA	6mA	6mA	4mA
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	-25°C ~ 85°C	-40°C ~ 105°C	0°C ~ 70°C
RoHS Status	ROHS3 Compliant	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

For Direct Replacement (Pin-Compatible, Identical Specifications): Select LM311DR2G (onsemi) or LM311DT (STMicroelectronics) when the LM311M/NOPB is unavailable. Both parts maintain identical electrical specifications and operating temperature range. LM311DR2G offers higher inventory availability (516,900 units). LM311DT provides specified output current (50mA) and is available in higher quantities (59,590 units). Both are ROHS3 compliant with unlimited MSL rating.

For Enhanced Performance Requirements: Select LM211DR2G (onsemi) or LM211DT (STMicroelectronics) when improved input offset voltage (3mV vs 7.5mV) and lower input bias current (0.1µA vs 0.25µA) are required. LM211DT extends operating temperature to -40°C ~ 105°C, suitable for industrial and automotive applications. LM211DR2G operates to -25°C ~ 85°C. Both reduce quiescent current to 6mA.

For Superior Precision and Low-Power Applications: Select LT1011CS8#PBF (Analog Devices Inc.) when the lowest input offset voltage (2mV), minimal input bias current (0.065µA), and lowest quiescent current (4mA) are critical. This part offers extended supply voltage range (3V ~ 36V) and specified CMRR (115dB). Inventory is limited (1,278 units).

Avoid: LM311D (National Semiconductor) is obsolete and non-compliant with ROHS3 standards. Use only if legacy system requirements mandate this specific part number.

Frequently Asked Questions (FAQ)

Q: Can LM211DR2G or LM211DT be used as direct replacements for LM311M/NOPB?

A: Yes, with design verification. Both LM211 variants are pin-compatible and meet all mandatory electrical specifications. The LM211 series offers improved input offset voltage (3mV vs 7.5mV) and lower input bias current (0.1µA vs 0.25µA). Extended operating temperature ranges (-25°C ~ 85°C for onsemi, -40°C ~ 105°C for STMicroelectronics) may provide additional margin for temperature-sensitive applications. Verify that the improved specifications do not introduce unintended circuit behavior changes.

Q: What is the difference between LM311DR2G and LM311DT?

A: Both maintain identical LM311 electrical specifications and 0°C ~ 70°C operating temperature. LM311DT (STMicroelectronics) specifies 50mA output current; LM311DR2G (onsemi) does not specify this parameter. LM311DT is available in higher quantities (59,590 units vs 516,900 units for LM311DR2G). Select based on availability and output current requirements.

Q: Is LT1011CS8#PBF a suitable substitute for general-purpose applications?

A: LT1011CS8#PBF is suitable when precision and low-power operation are required. Superior input offset voltage (2mV), input bias current (0.065µA), and quiescent current (4mA) make this part ideal for precision measurement and battery-powered circuits. However, inventory is limited (1,278 units). Verify that the Analog Devices part number and CMRR specification (115dB) align with circuit requirements before selection.

Q: Are all substitute parts ROHS3 compliant?

A: All active-status substitutes (LM311DR2G, LM311DT, LM211DR2G, LM211DT, LT1011CS8#PBF) are ROHS3 compliant. LM311D (National Semiconductor) is RoHS non-compliant and obsolete. For applications requiring ROHS3 certification, exclude LM311D from consideration.

Q: What is the impact of different supply voltage ranges on substitution?

A: LM311M/NOPB supports 5V ~ 36V single supply and ±2.5V ~ 18V dual supply. LM311D supports narrower ranges (4.6V ~ 30V, ±1.75V ~ 15V). LT1011CS8#PBF supports extended ranges (3V ~ 36V, ±1.5V ~ 18V). Verify that the selected substitute's supply voltage range encompasses the circuit's operating conditions. For applications requiring 36V single supply operation, LT1011CS8#PBF is the only alternative that matches the upper limit.

Q: Can LM311D be used in new designs?

A: No. LM311D is obsolete and RoHS non-compliant. Use only in legacy system maintenance where the original part number is mandated by design documentation or regulatory requirements. For new designs, select from active-status alternatives: LM311DR2G, LM311DT, LM211DR2G, LM211DT, or LT1011CS8#PBF.

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