KA311DTF Equivalent & Substitute Parts

Part Overview

The KA311DTF is a general-purpose comparator IC manufactured by onsemi in 8-SOIC surface mount packaging. This device features open-collector and open-emitter output configuration, supporting dual supply voltages from ±2.5V to ±15V and single supply from 5V to 30V. The KA311DTF is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	KA311DTF
Manufacturer	onsemi
Category	Linear Comparator
Type	General Purpose
Number of Elements	1
Output Type	Open-Collector, Open-Emitter
Voltage Supply (Single/Dual)	5V ~ 30V, ±2.5V ~ 15V
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
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected

Substitute Part Grouping Explanation

Substitution for the KA311DTF is determined by the following critical parameters:

Package Compatibility: The 8-SOIC (0.154", 3.90mm Width) surface mount package is the primary constraint. Substitutes maintaining this package form factor allow direct PCB replacement without layout modification.

Electrical Performance: Input offset voltage (7.5mV @ ±15V), input bias current (0.25µA @ ±15V), and quiescent current (7.5mA) define the functional equivalence window. Substitutes must meet or exceed these specifications.

Supply Voltage Range: Dual supply operation (±2.5V ~ ±15V) and single supply operation (5V ~ 30V) are essential for circuit compatibility. Substitutes supporting these ranges ensure drop-in replacement capability.

Output Configuration: Open-collector and open-emitter output types are required for interface compatibility with existing pull-up resistor networks and logic circuits.

Product Status: Active status substitutes provide ongoing availability and manufacturing support, addressing the obsolescence of the KA311DTF.

Substitutes are grouped into two categories:

Category 1 - Direct Package Match (8-SOIC): LM311DR2G, LM311DR, LM311DT, and LM311M/NOPB maintain identical 8-SOIC packaging, enabling direct PCB replacement.

Category 2 - Functional Equivalents (Alternate Packages): AZV331KTR-G1, LMV331IDBVR, and LMV331IDCKR provide comparable electrical performance in smaller surface mount packages (SOT-23-5, SC-70-5), suitable for space-constrained applications.

Parameter Comparison

Parameter	KA311DTF	LM311DR2G	LM311DR	LM311DT	LM311M/NOPB	LM211DT	LT1011IS8#TRPBF
Manufacturer	onsemi	onsemi	Texas Instruments	STMicroelectronics	Texas Instruments	STMicroelectronics	Analog Devices Inc.
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Output Type	Open-Collector, Open-Emitter	DTL, MOS, Open-Collector, Open-Emitter, RTL, TTL	MOS, Open-Collector, Open-Emitter, TTL	DTL, MOS, Open-Collector, Open-Emitter, RTL, TTL	DTL, MOS, Open-Collector, Open-Emitter, RTL, TTL	DTL, MOS, Open-Collector, Open-Emitter, RTL, TTL	Open-Collector
Voltage Supply (Single/Dual)	5V ~ 30V, ±2.5V ~ 15V	5V ~ 30V, ±2.5V ~ 15V	4.6V ~ 30V, ±1.75V ~ 15V	5V ~ 30V, ±2.5V ~ 15V	5V ~ 36V, ±2.5V ~ 18V	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	7.5mV @ ±15V	3mV @ ±15V	2mV @ ±15V
Current - Input Bias (Max)	0.25µA @ ±15V	0.25µA @ ±15V	0.25µA @ ±15V	0.25µA @ ±15V	0.25µA @ ±15V	0.1µA @ ±15V	0.065µA @ ±15V
Current - Quiescent (Max)	7.5mA	7.5mA	7.5mA	7.5mA	7.5mA	6mA	4mA
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	-40°C ~ 105°C	-40°C ~ 85°C
RoHS Status	Not specified	ROHS3 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)	1 (Unlimited)

Engineering Selection Recommendations

Primary Substitutes (8-SOIC Package):

LM311DR2G (onsemi) and LM311DT (STMicroelectronics) are recommended as primary substitutes. Both maintain the 8-SOIC package, identical electrical specifications, and active product status with ROHS3 compliance. LM311DR2G offers the highest inventory availability (516,900 units) and is supplied in Cut Tape and Digi-Reel packaging for production flexibility.

LM311DR (Texas Instruments) provides an alternative with slightly extended supply voltage range (4.6V ~ 30V single supply, ±1.75V ~ 15V dual supply) and active status. This part is suitable for applications requiring lower minimum supply voltages.

LM311M/NOPB (Texas Instruments) extends the supply voltage range further (5V ~ 36V single supply, ±2.5V ~ 18V dual supply) and is available in Tube packaging. This variant accommodates higher voltage applications while maintaining electrical equivalence.

Secondary Substitutes (Alternate Packages):

LT1011IS8#TRPBF (Analog Devices Inc.) offers superior electrical performance with lower input offset voltage (2mV @ ±15V), lower input bias current (0.065µA @ ±15V), and lower quiescent current (4mA). The 8-SOIC package maintains PCB compatibility. Extended operating temperature range (-40°C ~ 85°C) and CMRR specification (115dB) provide enhanced performance for precision applications. Limited inventory (1,101 units) may impact availability.

Functional Equivalents (Compact Packages):

AZV331KTR-G1 (Diodes Incorporated) and LMV331IDBVR/LMV331IDCKR (Texas Instruments) provide functional equivalence in smaller surface mount packages (SOT-23-5, SC-70-5). These parts operate at reduced supply voltages (2.5V ~ 5.5V or 2.7V ~ 5.5V) and are suitable for low-voltage applications. Package change requires PCB layout modification but enables space optimization in compact designs.

Frequently Asked Questions (FAQ)

Q: Can LM311DR2G directly replace KA311DTF on existing PCBs?

A: Yes. LM311DR2G maintains identical 8-SOIC packaging, electrical specifications (7.5mV input offset, 0.25µA input bias, 7.5mA quiescent current), and supply voltage range (5V ~ 30V single, ±2.5V ~ 15V dual). Direct PCB replacement is possible without layout modification.

Q: What is the difference between LM311DR and LM311DR2G?

A: Both parts are manufactured by onsemi and maintain identical electrical performance and 8-SOIC packaging. LM311DR2G is the current production variant with active status and ROHS3 compliance. LM311DR is an alternative designation. Verify current availability with your supplier.

Q: Why do some substitutes have different supply voltage ranges?

A: Different manufacturers optimize their designs for specific voltage domains. LM311DR (Texas Instruments) supports lower minimum single supply (4.6V vs. 5V) and dual supply (±1.75V vs. ±2.5V). LM311M/NOPB extends maximum ratings (36V single, ±18V dual). Select based on your circuit's supply voltage requirements.

Q: Can I use LT1011IS8#TRPBF as a substitute?

A: Yes, with performance advantages. LT1011IS8#TRPBF maintains 8-SOIC packaging and open-collector output. It offers superior specifications: lower input offset (2mV vs. 7.5mV), lower input bias current (0.065µA vs. 0.25µA), and lower quiescent current (4mA vs. 7.5mA). Extended operating temperature (-40°C ~ 85°C) and CMRR specification (115dB) suit precision applications. Limited inventory may require lead time planning.

Q: Are AZV331KTR-G1 and LMV331 series drop-in replacements?

A: No. These parts use SOT-23-5 and SC-70-5 packages, requiring PCB layout modification. They operate at reduced supply voltages (2.5V ~ 5.5V or 2.7V ~ 5.5V), incompatible with ±15V dual supply circuits. Use only in new designs optimized for low-voltage operation or when space constraints justify redesign.

Q: What is the inventory status for substitutes?

A: LM311DR2G has the highest availability (516,900 units). LM311DT (59,590 units) and LMV331IDBVR (89,300 units) offer substantial stock. LT1011IS8#TRPBF has limited inventory (1,101 units). Verify current stock with your distributor before design commitment.

Q: Do all substitutes meet ROHS3 compliance?

A: Yes. All active substitutes listed carry ROHS3 compliance certification. The original KA311DTF does not specify RoHS status due to its obsolete classification. All substitutes maintain REACH Unaffected status and MSL 1 (Unlimited) moisture sensitivity rating.

Q: Which substitute offers the best performance for precision applications?

A: LT1011IS8#TRPBF provides the best performance specifications: 2mV input offset voltage, 0.065µA input bias current, 115dB CMRR, and 4mA quiescent current. These characteristics suit precision measurement and low-noise applications. Verify availability and lead time due to limited stock.

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