LM239AMX Equivalent & Substitute Parts

Part Overview

The LM239AMX is a 4-channel general-purpose comparator manufactured by onsemi in 14-SOP surface-mount packaging. This device features DTL, MOS, open-collector, and TTL output configurations with a supply voltage range of 2V to 36V (single) or ±1V to ±18V (dual). The LM239AMX is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM239AMX
Manufacturer	onsemi
Category	Linear Comparator
Number of Elements	4
Output Type	DTL, MOS, Open-Collector, TTL
Voltage - Supply, Single/Dual (±)	2V ~ 36V, ±1V ~ 18V
Voltage - Input Offset (Max)	2mV @ 5V
Current - Input Bias (Max)	0.25µA @ 5V
Current - Output (Typ)	18mA @ 5V
Current - Quiescent (Max)	2mA
Operating Temperature	-25°C ~ 85°C
Package / Case	14-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the LM239AMX is determined by the following critical parameters:

Package compatibility: 14-SOIC (0.154", 3.90mm Width) or 14-SOP form factor
Functional equivalence: 4-channel general-purpose comparator with open-collector output capability
Electrical compatibility: Supply voltage range must encompass or match 2V ~ 36V (single) or ±1V ~ ±18V (dual)
Output type: Open-collector output required for direct substitution
Input offset voltage: Maximum 7mV @ 5V acceptable for general-purpose applications
Input bias current: Maximum 0.25µA @ 5V
Output current: Minimum 16mA @ 5V
Quiescent current: Maximum 2.5mA
Compliance: ROHS3 compliant, MSL rating 1 or 3

Substitute parts are grouped by manufacturer and product status (active vs. obsolete/last-time-buy). Active parts are preferred for new designs.

Parameter Comparison

Part Number	Manufacturer	Product Status	Supply Voltage (Single/Dual)	Input Offset (Max)	Output Current (Typ)	Quiescent Current (Max)	Operating Temp	Package	Output Type
LM239AMX	onsemi	Obsolete	2V ~ 36V, ±1V ~ 18V	2mV @ 5V	18mA @ 5V	2mA	-25°C ~ 85°C	14-SOIC	DTL, MOS, Open-Collector, TTL
LM239DR2G	onsemi	Active	3V ~ 36V, ±1.5V ~ 18V	5mV @ 5V	16mA @ 5V	2.5mA	-25°C ~ 85°C	14-SOIC	CMOS, Open-Collector, TTL
LM2901DR2G	onsemi	Active	3V ~ 36V, ±1.5V ~ 18V	7mV @ 5V	16mA @ 5V	2.5mA	-40°C ~ 105°C	14-SOIC	CMOS, Open-Collector, TTL
LM2901VDR2G	onsemi	Active	3V ~ 36V, ±1.5V ~ 18V	7mV @ 5V	16mA @ 5V	2.5mA	-40°C ~ 125°C	14-SOIC	CMOS, Open-Collector, TTL
LM339DR2G	onsemi	Active	3V ~ 36V, ±1.5V ~ 18V	5mV @ 5V	16mA @ 5V	2.5mA	0°C ~ 70°C	14-SOIC	CMOS, Open-Collector, TTL
AS339AMTR-E1	Diodes Incorporated	Active	2V ~ 36V, ±1V ~ 18V	3mV @ 5V	16mA @ 5V	2mA	-40°C ~ 85°C	14-SOIC	Open-Collector
AS339MTR-E1	Diodes Incorporated	Active	2V ~ 36V, ±1V ~ 18V	5mV @ 5V	16mA @ 5V	2mA	-40°C ~ 85°C	14-SOIC	Open-Collector
BA2901SF-E2	Rohm Semiconductor	Active	2V ~ 36V, ±1V ~ 18V	7mV @ 5V	16mA @ 5V	2mA	-40°C ~ 105°C	14-SOIC	Open-Collector
LM139AD	Texas Instruments	Last Time Buy	2V ~ 30V, ±1V ~ 15V	2mV @ 30V	20mA	2mA	-55°C ~ 125°C	14-SOIC	Open-Collector, Open-Drain
LM139ADG4	Texas Instruments	Obsolete	2V ~ 30V, ±1V ~ 15V	2mV @ 30V	20mA	2mA	-55°C ~ 125°C	14-SOIC	Open-Collector, Open-Drain
LM139ADR	Texas Instruments	Active	2V ~ 30V, ±1V ~ 15V	2mV @ 30V	20mA	2mA	-55°C ~ 125°C	14-SOIC	Open-Collector, Open-Drain

Engineering Selection Recommendations

Primary Substitutes (onsemi LM239/LM2901 Series)

LM239DR2G and LM2901DR2G are direct onsemi alternatives with active product status. Both maintain the 14-SOIC package and open-collector output configuration. LM239DR2G operates within -25°C to 85°C, matching the original temperature range. LM2901DR2G extends the operating range to -40°C to 105°C, suitable for industrial applications. The minimum supply voltage increases from 2V to 3V for single supply, and dual supply from ±1V to ±1.5V. LM2901VDR2G provides the widest temperature range (-40°C to 125°C) for extended-temperature applications.

Secondary Substitutes (Diodes Incorporated AS339 Series)

AS339AMTR-E1 and AS339MTR-E1 maintain the original 2V to 36V supply voltage range and ±1V to ±18V dual supply specification, providing the closest electrical match to LM239AMX. Both are active products in 14-SOIC packaging with open-collector output. AS339AMTR-E1 offers superior input offset voltage (3mV @ 5V) compared to the original 2mV specification. Operating temperature extends to -40°C to 85°C.

Alternative Substitute (Rohm Semiconductor BA2901SF-E2)

BA2901SF-E2 is an active product matching the original supply voltage range (2V ~ 36V, ±1V ~ 18V) with extended operating temperature (-40°C to 105°C). The 14-SOP package is mechanically compatible with 14-SOIC footprints. Input offset voltage is 7mV @ 5V, within acceptable limits for general-purpose comparator applications.

Extended-Range Substitutes (Texas Instruments LM139 Series)

LM139ADR is the recommended active product from Texas Instruments. It provides open-collector and open-drain output options with superior input offset voltage (2mV @ 30V) and higher output current (20mA). The operating temperature range extends to -55°C to 125°C. Supply voltage is limited to 2V ~ 30V (single) and ±1V ~ ±15V (dual), which is acceptable for most applications within the original specification. LM139AD and LM139ADG4 are available but classified as last-time-buy and obsolete respectively.

Compliance and Certification

All substitute parts are ROHS3 compliant and carry MSL ratings of 1 (unlimited) or 3 (168 hours), meeting standard moisture sensitivity requirements. REACH status is unaffected for all listed alternatives.

Frequently Asked Questions (FAQ)

Q: Can LM239DR2G directly replace LM239AMX in existing designs?

A: LM239DR2G is mechanically and functionally compatible in 14-SOIC packaging. The minimum single supply voltage increases from 2V to 3V, and dual supply from ±1V to ±1.5V. Designs operating above these thresholds require no circuit modifications. Input offset voltage increases from 2mV to 5mV @ 5V, acceptable for general-purpose comparator applications.

Q: What is the key difference between onsemi LM239 and LM2901 series?

A: Both are 4-channel general-purpose comparators in 14-SOIC packaging with open-collector output. LM2901 variants offer extended operating temperature ranges (up to 125°C for LM2901VDR2G) compared to LM239DR2G (-25°C to 85°C). Input offset voltage is slightly higher for LM2901 (7mV @ 5V vs. 5mV @ 5V for LM239DR2G).

Q: Are Diodes Incorporated AS339 parts pin-compatible with LM239AMX?

A: Yes. AS339AMTR-E1 and AS339MTR-E1 are 14-SOIC pin-compatible devices with identical pinout. Both maintain the original supply voltage range (2V ~ 36V, ±1V ~ 18V) and open-collector output configuration. The primary difference is packaging format: AS339AMTR-E1 is supplied in tape and reel, while AS339MTR-E1 is cut tape with digi-reel.

Q: Can LM139ADR replace LM239AMX despite different part numbers?

A: LM139ADR is functionally equivalent as a 4-channel general-purpose comparator in 14-SOIC packaging with open-collector output. The supply voltage range is narrower (2V ~ 30V single, ±1V ~ ±15V dual) compared to LM239AMX (2V ~ 36V, ±1V ~ ±18V). Applications requiring supply voltages above 30V single or ±15V dual are not compatible. LM139ADR is an active product with extended temperature range (-55°C to 125°C).

Q: What is the difference between 14-SOIC and 14-SOP packaging?

A: Both are 14-pin surface-mount packages with identical 0.154" (3.90mm) body width. 14-SOP (small outline package) and 14-SOIC (small outline integrated circuit) are functionally interchangeable for PCB footprint purposes. BA2901SF-E2 uses 14-SOP (0.173", 4.40mm width variant), which is mechanically compatible with standard 14-SOIC footprints.

Q: Which substitute part offers the best input offset voltage specification?

A: AS339AMTR-E1 provides the lowest input offset voltage among active substitutes at 3mV @ 5V, compared to LM239AMX at 2mV @ 5V. LM139ADR matches the original specification at 2mV @ 30V. For applications requiring minimal offset voltage, AS339AMTR-E1 or LM139ADR are preferred.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification. Moisture sensitivity levels are MSL 1 (unlimited) for most parts, with AS339MTR-E1 rated MSL 3 (168 hours). Standard PCB assembly processes accommodate both MSL ratings.

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