LM124D Equivalent & Substitute Parts

Part Overview

The LM124D is a general-purpose operational amplifier integrated circuit manufactured by STMicroelectronics, configured as a 4-circuit differential amplifier in a 14-SOIC surface mount package. This device is classified as obsolete, indicating discontinued production and limited availability for new designs. The LM124D operates across a wide supply voltage range of 3V to 30V and is suitable for applications requiring low-cost, general-purpose amplification with moderate performance specifications.

Due to its obsolete status, identifying equivalent and substitute parts is necessary for design continuity, component sourcing, and long-term product support. Active alternatives with comparable or enhanced electrical characteristics are available from multiple manufacturers.

Key Parameters

Parameter	Value	Unit
Amplifier Type	General Purpose	—
Number of Circuits	4	—
Output Type	Differential	—
Slew Rate	0.4	V/µs
Gain Bandwidth Product	1.2	MHz
Current - Input Bias	20	nA
Voltage - Input Offset	2	mV
Current - Supply	1.5	mA
Current - Output / Channel	30	mA
Voltage - Supply Span (Min)	3	V
Voltage - Supply Span (Max)	30	V
Operating Temperature Range	-55 to 125	°C
Package / Case	14-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the LM124D is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Package type: 14-SOIC (0.154", 3.90mm Width) surface mount configuration
Number of circuits: 4 independent amplifier channels
Supply voltage range: Minimum 3V to maximum 30V (or compatible subset)
Amplifier type: General-purpose or equivalent topology
Mounting type: Surface mount

Performance Considerations: Substitute parts are grouped into two categories based on amplifier topology:

General-Purpose Amplifiers (Direct Substitutes): Parts with general-purpose amplifier topology, matching the LM124D's input bias current (20 nA), input offset voltage (2 mV), and supply voltage specifications. These include ADA4004 variants and AS324 variants from Diodes Incorporated.
J-FET Amplifiers (Enhanced Performance Alternatives): Parts with J-FET input topology, such as ADTL084 variants, offering superior input bias current (2 pA) and higher slew rate (20 V/µs) at the cost of higher minimum supply voltage (8V minimum).

All substitute parts maintain 14-SOIC package compatibility, surface mount configuration, and ROHS3 compliance. Selection between groups depends on application requirements for input bias current, slew rate, and minimum supply voltage.

Parameter Comparison

Parameter	LM124D	ADA4004-4ARZ	ADA4004-4ARZ-R7	ADA4004-4ARZ-RL	ADTL084ARZ	ADTL084ARZ-REEL	ADTL084ARZ-REEL7	AS324AMTR-E1	AS324AMTR-G1	AS324MTR-E1	AS324MTR-G1
Manufacturer	STMicroelectronics	Analog Devices	Analog Devices	Analog Devices	Analog Devices	Analog Devices	Analog Devices	Diodes Inc.	Diodes Inc.	Diodes Inc.	Diodes Inc.
Amplifier Type	General Purpose	General Purpose	General Purpose	General Purpose	J-FET	J-FET	J-FET	General Purpose	General Purpose	General Purpose	General Purpose
Number of Circuits	4	4	4	4	4	4	4	4	4	4	4
Slew Rate (V/µs)	0.4	2.7	2.7	2.7	20	20	20	—	—	—	—
Gain Bandwidth Product (MHz)	1.2	12	12	12	5	5	5	—	—	—	—
Current - Input Bias (nA)	20	40	40	40	0.002	0.002	0.002	20	20	20	20
Voltage - Input Offset (mV)	2	0.04	0.04	0.04	1.5	1.5	1.5	2	2	2	2
Current - Output / Channel (mA)	30	10	10	10	27	27	27	40	40	40	40
Voltage - Supply Span Min (V)	3	10	10	10	8	8	8	3	3	3	3
Voltage - Supply Span Max (V)	30	30	30	30	36	36	36	36	36	36	36
Operating Temperature (°C)	-55 to 125	-40 to 125	-40 to 125	-40 to 125	-40 to 125	-40 to 125	-40 to 125	-40 to 85	-40 to 85	-40 to 85	-40 to 85
Package / Case	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)	3 (168 Hours)	3 (168 Hours)	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	3 (168 Hours)	1 (Unlimited)

Engineering Selection Recommendations

For Direct Replacement with Enhanced Performance:

The AS324AMTR-G1 and AS324MTR-G1 from Diodes Incorporated provide the most direct substitution path for the LM124D. Both parts maintain identical input bias current (20 nA), input offset voltage (2 mV), and supply voltage range (3V to 36V). These devices are active products with ROHS3 compliance and MSL 1 rating, ensuring long-term availability and handling compatibility. The AS324MTR-G1 offers the highest inventory availability (196,751 pieces) and is suitable for applications requiring the original LM124D electrical characteristics without modification.

For Applications Requiring Extended Temperature Range:

The LM124D operates from -55°C to 125°C. Substitute parts from Diodes Incorporated (AS324 series) operate from -40°C to 85°C, representing a narrower temperature range. If the full -55°C to 125°C range is required, the ADA4004 series from Analog Devices extends to -40°C to 125°C, providing the upper temperature limit match. However, the ADA4004 series requires a minimum supply voltage of 10V, which may not be compatible with applications using the LM124D's 3V minimum specification.

For Low Input Bias Current Applications:

The ADTL084 series (ADTL084ARZ, ADTL084ARZ-REEL, ADTL084ARZ-REEL7) from Analog Devices provides J-FET input topology with input bias current of 2 pA, approximately 10,000 times lower than the LM124D. These devices are suitable for high-impedance signal conditioning applications. The ADTL084ARZ-REEL7 variant offers the highest inventory (44,200 pieces) and MSL 1 rating. The minimum supply voltage requirement of 8V must be verified against application constraints.

For High-Speed Applications:

The ADA4004 series delivers a gain bandwidth product of 12 MHz and slew rate of 2.7 V/µs, compared to the LM124D's 1.2 MHz and 0.4 V/µs. The ADTL084 series provides even higher performance with 5 MHz gain bandwidth product and 20 V/µs slew rate. Selection between these options depends on the minimum supply voltage requirement and the application's bandwidth specifications.

Compliance and Availability Considerations:

All substitute parts listed maintain ROHS3 compliance and REACH unaffected status, matching the LM124D's regulatory compliance profile. Moisture sensitivity levels vary: AS324 variants with MSL 1 rating (unlimited shelf life) are preferred for long-term storage, while ADA4004 variants with MSL 3 rating (168 hours) require controlled storage conditions. The ADTL084 series maintains MSL 1 rating across all packaging options.

Frequently Asked Questions (FAQ)

Q: Can the AS324AMTR-G1 be used as a direct replacement for the LM124D without circuit modification?

A: The AS324AMTR-G1 is electrically compatible with the LM124D for applications operating within the -40°C to 85°C temperature range. Both devices share identical input bias current (20 nA), input offset voltage (2 mV), and supply voltage specifications (3V to 36V). The 14-SOIC package pinout is identical. No circuit modification is required for standard general-purpose amplifier applications. However, applications requiring operation below -40°C or above 85°C require alternative selection.

Q: What is the primary limitation of using ADA4004 variants as substitutes for the LM124D?

A: The ADA4004 series requires a minimum supply voltage of 10V, whereas the LM124D operates from 3V minimum. Applications designed for 3V to 9V supply operation cannot use ADA4004 variants without circuit redesign. The ADA4004 series is suitable only for applications with supply voltages of 10V or higher.

Q: Why do ADTL084 variants require a minimum supply voltage of 8V when the LM124D operates from 3V?

A: The ADTL084 series uses J-FET input topology, which requires higher bias voltages for proper operation compared to the bipolar input stage of the LM124D. This is a fundamental characteristic of J-FET input amplifiers and cannot be modified through circuit design. Applications with supply voltages below 8V must use general-purpose amplifier variants (AS324 or ADA4004 series) rather than J-FET types.

Q: Are all substitute parts available in the same packaging options as the LM124D?

A: All substitute parts are available in 14-SOIC surface mount packages matching the LM124D's physical footprint. However, packaging variants differ by supplier and tape/reel configuration. The LM124D is supplied in 14-SO format. Equivalent parts are available in 14-SOIC format with identical pin spacing (0.154", 3.90mm width). Verify specific packaging requirements with the component supplier before procurement.

Q: What is the significance of Moisture Sensitivity Level (MSL) ratings when selecting substitutes?

A: MSL 1 rated components (LM124D, ADTL084 series, AS324AMTR-E1, AS324AMTR-G1, AS324MTR-G1) have unlimited shelf life and do not require controlled humidity storage. MSL 3 rated components (ADA4004 series, AS324MTR-E1) must be stored in controlled humidity environments for a maximum of 168 hours after opening the original packaging. For applications with extended procurement cycles or inventory management requirements, MSL 1 components are preferred.

Q: Can the ADTL084 series be used in applications originally designed for the LM124D?

A: The ADTL084 series is electrically compatible with the LM124D in applications where the minimum 8V supply voltage requirement is met. The ADTL084 offers superior performance characteristics: input bias current of 2 pA (versus 20 nA), slew rate of 20 V/µs (versus 0.4 V/µs), and gain bandwidth product of 5 MHz (versus 1.2 MHz). These enhancements make the ADTL084 suitable for high-impedance signal conditioning and faster signal processing applications. However, the higher supply voltage requirement and increased cost must be evaluated against application benefits.

Q: What is the difference between ADA4004-4ARZ, ADA4004-4ARZ-R7, and ADA4004-4ARZ-RL packaging variants?

A: All three ADA4004 variants are electrically identical with identical electrical specifications. The differences are in packaging and delivery format: ADA4004-4ARZ is supplied in tube packaging, ADA4004-4ARZ-R7 is supplied in cut tape and Digi-Reel format, and ADA4004-4ARZ-RL is supplied in tape and reel format. Selection depends on assembly equipment compatibility and procurement volume requirements. Electrical performance and pin configuration are identical across all three variants.

Q: Is the LM124D's differential output type a critical factor when selecting substitutes?

A: The LM124D is specified with differential output type. Most substitute parts do not explicitly specify output type in the provided data. In standard operational amplifier configurations, output type refers to the amplifier's output stage topology. For general-purpose amplifier applications, the absence of explicit output type specification in substitute parts does not indicate incompatibility. Verify specific application requirements with the component datasheet if differential output characteristics are critical to circuit function.

Q: Which substitute part offers the best balance of performance, availability, and cost for general-purpose applications?

A: The AS324MTR-G1 from Diodes Incorporated provides optimal balance for general-purpose amplifier applications. It maintains electrical compatibility with the LM124D (20 nA input bias current, 2 mV input offset voltage, 3V to 36V supply range), offers the highest inventory availability (196,751 pieces), maintains MSL 1 rating for unlimited shelf life, and is an active product with long-term support. The 14-SOIC package is identical to the LM124D, and ROHS3 compliance matches regulatory requirements.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message