LMX324ASD+ Equivalent & Substitute Parts Reference

Part Overview

The LMX324ASD+ is a general-purpose operational amplifier featuring four independent circuits in a 14-SOIC surface-mount package. Manufactured by Analog Devices Inc./Maxim Integrated, this device provides rail-to-rail output capability with a 1.3 MHz gain-bandwidth product and operates across a 2.3 V to 7 V supply range. The LMX324ASD+ is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and ongoing production requirements. Substitute parts must maintain functional compatibility while meeting current availability and product status requirements.

Key Parameters

Parameter	LMX324ASD+	Unit
Amplifier Type	General Purpose	—
Number of Circuits	4	Channels
Output Type	Rail-to-Rail	—
Package / Case	14-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
Slew Rate	1	V/µs
Gain Bandwidth Product	1.3	MHz
Current - Input Bias	18	nA
Voltage - Input Offset	1	mV
Current - Supply (x4 Channels)	480	µA
Current - Output / Channel	70	mA
Voltage - Supply Span (Min)	2.3	V
Voltage - Supply Span (Max)	7	V
Operating Temperature	-40 to 125	°C
RoHS Status	ROHS3 Compliant	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution eligibility for the LMX324ASD+ is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Four independent operational amplifier circuits
Rail-to-rail output configuration
14-SOIC surface-mount package (0.154", 3.90mm width)
Operating temperature range of -40°C to 125°C (or compatible subset)
Supply voltage range compatibility with 2.3 V to 7 V operation

Performance Parameters Affecting Substitution:

Slew rate (1 V/µs baseline)
Gain-bandwidth product (1.3 MHz baseline)
Input bias current (18 nA baseline)
Input offset voltage (1 mV baseline)
Supply current per channel (480 µA baseline)
Output current per channel (70 mA baseline)

Substitute parts are grouped into two categories based on product status and parameter alignment:

Category 1: Active Status Substitutes with Enhanced or Equivalent Performance Parts including AD8544ARZ, AD8544ARZ-REEL, AD8544ARZ-REEL7, AD8544WARZ-R7, ISL28413FBZ, and ISL28413FBZ-T7 maintain active product status and provide improved specifications in key areas such as input bias current and supply current efficiency.

Category 2: Active Status Substitutes with Comparable Performance Parts including MAX4294ESD+, LMV324BG-13, LMV324DR2G, and LMV324ID provide functional equivalence with active availability, though certain parameters may differ from the original specification.

Parameter Comparison

Parameter	LMX324ASD+	MAX4294ESD+	AD8544ARZ	ISL28413FBZ	LMV324BG-13	LMV324ID	Unit
Manufacturer	Analog Devices Inc./Maxim Integrated	Analog Devices Inc./Maxim Integrated	Analog Devices Inc.	Renesas Electronics Corporation	Diodes Incorporated	Texas Instruments	—
Product Status	Obsolete	Active	Active	Active	Active	Last Time Buy	—
Number of Circuits	4	4	4	4	4	4	Channels
Output Type	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	—
Package / Case	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	—
Slew Rate	1	0.2	0.92	1	1	1	V/µs
Gain Bandwidth Product	1.3	0.5	1	2	1	1	MHz
Current - Input Bias	18	15	4	3	15	15	nA
Voltage - Input Offset	1	0.2	1	0.5	1.7	1.7	mV
Current - Supply (x4 Channels)	480	100	45	90	340	410	µA
Current - Output / Channel	70	20	30	22	90	40	mA
Voltage - Supply Span (Min)	2.3	1.8	2.7	1.8	2.7	2.7	V
Voltage - Supply Span (Max)	7	5.5	5.5	5.5	5.5	5.5	V
Operating Temperature	-40 to 125	-40 to 85	-40 to 125	-40 to 125	-40 to 125	-40 to 125	°C
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

Primary Recommendation: AD8544ARZ Series

The AD8544ARZ, AD8544ARZ-REEL, AD8544ARZ-REEL7, and AD8544WARZ-R7 represent the preferred substitutes for the LMX324ASD+. These parts maintain active product status with Analog Devices Inc. manufacturing, ensuring long-term availability and supply chain stability. The AD8544 series demonstrates superior input bias current performance (4 pA versus 18 nA) and significantly reduced supply current consumption (45 µA versus 480 µA), providing direct functional replacement with improved power efficiency. Operating temperature range extends to -40°C to 125°C, matching the original specification. All variants comply with ROHS3 and maintain identical 14-SOIC packaging.

Secondary Recommendation: ISL28413FBZ Series

The ISL28413FBZ and ISL28413FBZ-T7 from Renesas Electronics Corporation provide active-status alternatives with enhanced gain-bandwidth product (2 MHz versus 1.3 MHz) and superior input bias current (3 pA). These parts support the full -40°C to 125°C operating temperature range and maintain 14-SOIC packaging compatibility. Supply current efficiency is improved at 90 µA per channel. Moisture sensitivity level is rated at MSL 2 (1 Year), compared to MSL 1 for the original part.

Tertiary Recommendation: LMV324ID

The LMV324ID from Texas Instruments maintains active availability under Last Time Buy status. This part provides direct parameter compatibility with the LMX324ASD+ across slew rate, gain-bandwidth product, and operating temperature range. The 14-SOIC package and rail-to-rail output configuration ensure mechanical and electrical compatibility. Supply current is 410 µA per channel, and output current capability is 40 mA per channel.

Alternative Consideration: MAX4294ESD+

The MAX4294ESD+ from Analog Devices Inc./Maxim Integrated is active and available. This part operates within a reduced supply voltage range (1.8 V to 5.5 V) and maximum operating temperature of 85°C, which may limit applicability in designs requiring the full -40°C to 125°C range or higher supply voltages. The slew rate is reduced to 0.2 V/µs and gain-bandwidth product is 0.5 MHz, representing lower performance in dynamic response characteristics.

Compliance and Certification:

All recommended substitute parts maintain ROHS3 compliance and REACH unaffected status, matching the original LMX324ASD+ certifications. ECCN classification remains EAR99 across all alternatives.

Frequently Asked Questions (FAQ)

Q1: Can the AD8544ARZ directly replace the LMX324ASD+ in existing PCB designs?

A: Yes. The AD8544ARZ maintains identical 14-SOIC package dimensions (0.154", 3.90mm width) and pinout configuration. Pin-for-pin compatibility is confirmed. No PCB layout modifications are required. The part operates across the -40°C to 125°C temperature range and supports the required supply voltage specifications for most applications operating within the 2.7 V to 5.5 V range. Applications requiring supply voltages above 5.5 V will require design review.

Q2: What is the primary advantage of substituting to the AD8544 series?

A: The AD8544 series provides significant power consumption reduction. Supply current is reduced from 480 µA to 45 µA per channel (approximately 90% reduction), while input bias current improves from 18 nA to 4 pA. These improvements are particularly beneficial in battery-powered and low-power applications. Functional performance remains equivalent or superior across all critical parameters.

Q3: Why is the MAX4294ESD+ listed as a substitute if it has lower performance specifications?

A: The MAX4294ESD+ is included as a substitute option for applications where the reduced slew rate (0.2 V/µs) and lower gain-bandwidth product (0.5 MHz) are acceptable. This part is suitable for low-frequency signal conditioning and precision measurement applications where dynamic response is not critical. The reduced operating temperature maximum (85°C) and supply voltage maximum (5.5 V) restrict its use to designs operating within these constraints.

Q4: What is the difference between AD8544ARZ, AD8544ARZ-REEL, AD8544ARZ-REEL7, and AD8544WARZ-R7?

A: These variants represent different packaging and tape-reel configurations for the same AD8544 operational amplifier die. AD8544ARZ is supplied in tube packaging. AD8544ARZ-REEL and AD8544ARZ-REEL7 are supplied on cut tape and Digi-Reel®. AD8544WARZ-R7 is supplied on tape and reel (TR). All variants have identical electrical specifications and 14-SOIC package dimensions. Selection depends on procurement and assembly requirements.

Q5: Is the ISL28413FBZ suitable for high-frequency applications?

A: The ISL28413FBZ provides a 2 MHz gain-bandwidth product, which exceeds the LMX324ASD+ specification of 1.3 MHz. This part is suitable for applications requiring higher bandwidth performance. The slew rate of 1 V/µs matches the original specification. Input offset voltage is improved at 500 µV. This part is recommended for applications requiring enhanced frequency response.

Q6: What are the supply voltage compatibility considerations?

A: The LMX324ASD+ operates from 2.3 V to 7 V. Most substitute parts operate from 2.7 V to 5.5 V, representing a narrower range. The MAX4294ESD+ operates from 1.8 V to 5.5 V. Applications requiring operation above 5.5 V or below 2.7 V must retain the LMV324ID (2.7 V to 5.5 V) or verify alternative solutions. The AD8544 series (2.7 V to 5.5 V) is suitable for standard industrial and consumer applications.

Q7: Are all substitute parts RoHS3 compliant?

A: Yes. All recommended substitute parts maintain ROHS3 compliance and REACH unaffected status, matching the original LMX324ASD+ certifications. This ensures compatibility with environmental and regulatory requirements across global markets.

Q8: What is the moisture sensitivity level (MSL) impact?

A: The LMX324ASD+ is rated MSL 1 (Unlimited). Most substitute parts maintain MSL 1 or MSL 2 (1 Year). The ISL28413 series is rated MSL 2. MSL 2 requires storage in controlled humidity environments and has a one-year shelf life from the date of manufacture. For high-volume production with extended storage, MSL 1 parts (AD8544, LMV324ID) are preferred.

Q9: Can the LMV324BG-13 be used as a direct substitute?

A: The LMV324BG-13 from Diodes Incorporated provides functional compatibility with identical slew rate (1 V/µs) and gain-bandwidth product (1 MHz). The 14-SOIC package is compatible. However, the supplier device package is listed as 14-SO (versus 14-SOIC for the original), which may indicate minor physical differences. Output current capability is higher at 90 mA per channel. This part is suitable for applications where higher output current is beneficial.

Q10: What is the Last Time Buy status of the LMV324ID?

A: Last Time Buy status indicates that Texas Instruments has announced end-of-life for the LMV324ID and will accept orders only until a specified cutoff date. After this date, the part will no longer be available. This part should be considered for existing designs requiring extended support but is not recommended for new designs. The AD8544 series is preferred for new development due to indefinite active status.

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