LM324NG Equivalent & Substitute Parts

Part Overview

The LM324NG is a general-purpose operational amplifier integrated circuit manufactured by onsemi, featuring four independent amplifier circuits in a 14-DIP package. This device is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and procurement.

The LM324NG operates across a supply voltage range of 3V to 32V with an operating temperature range of 0°C to 70°C. With a gain bandwidth product of 1 MHz, input bias current of 90 nA, and output current capability of 40 mA per channel, this component serves general-purpose amplification applications requiring moderate bandwidth and low input bias characteristics.

Due to its obsolete status, alternative components with compatible electrical and mechanical specifications are necessary for system maintenance, redesign, and new production implementations.

Key Parameters

Parameter	LM324NG Value	Unit
Amplifier Type	General Purpose	—
Number of Circuits	4	—
Gain Bandwidth Product	1 MHz	MHz
Current - Input Bias	90 nA	nA
Voltage - Input Offset	2 mV	mV
Current - Output / Channel	40 mA	mA
Voltage - Supply Span (Min)	3 V	V
Voltage - Supply Span (Max)	32 V	V
Operating Temperature	0°C ~ 70°C	°C
Package / Case	14-DIP (0.300", 7.62mm)	—
Mounting Type	Through Hole	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitute components for the LM324NG are categorized based on strict adherence to the following electrical and mechanical compatibility criteria:

Primary Substitution Criteria:

Four independent amplifier circuits in single package
14-DIP through-hole package format (0.300", 7.62mm)
Supply voltage range compatibility: minimum 3V, maximum 32V or greater
Operating temperature range: 0°C to 70°C or extended range
Output current capability: 40 mA per channel or greater
Input bias current: 90 nA or lower
Input offset voltage: 2 mV to 5 mV range

Grouping Logic:

Group 1: General Purpose Amplifiers (Direct Functional Equivalents) Components KA324A, LM324NE3, LM224AN, LM224KAN, and LM224KN maintain the general-purpose amplifier classification with four circuits, identical package format, and compatible supply voltage specifications. These parts satisfy direct substitution requirements for applications requiring moderate bandwidth and standard input bias characteristics.

Group 2: J-FET Input Amplifiers (Enhanced Performance Alternatives) Components LF347BN, LF347N, LF347N/NOPB, LF444ACN/NOPB, and LF444CN/NOPB feature J-FET input stages with significantly lower input bias current (10 pA to 50 pA range) and higher gain bandwidth products (4 MHz). These devices require higher supply voltage spans (36V to 44V) and are suitable for applications demanding ultra-low input bias current and higher bandwidth performance.

Substitution between general-purpose and J-FET groups requires verification of supply voltage availability and application bandwidth requirements.

Parameter Comparison

Part Number	Manufacturer	Amplifier Type	Gain Bandwidth Product (MHz)	Input Bias Current (nA/pA)	Input Offset Voltage (mV)	Output Current / Channel (mA)	Supply Span Min (V)	Supply Span Max (V)	Operating Temp (°C)	Product Status
LM324NG	onsemi	General Purpose	1	90 nA	2	40	3	32	0 ~ 70	Obsolete
KA324A	Fairchild Semiconductor	General Purpose	—	40 nA	1.5	40	3	32	0 ~ 70	Active
LM324NE3	Texas Instruments	General Purpose	1.2	45 nA	2	40	3	32	0 ~ 70	Last Time Buy
LF347BN	onsemi	J-FET	4	50 pA	3	40	36	36	0 ~ 70	Obsolete
LF347N	STMicroelectronics	J-FET	4	20 pA	3	40	44	44	0 ~ 70	Obsolete
LF347N/NOPB	Texas Instruments	J-FET	4	50 pA	5	40	36	36	0 ~ 70	Active
LF444ACN/NOPB	Texas Instruments	J-FET	1	10 pA	2	14	44	44	0 ~ 70	Active
LF444CN/NOPB	Texas Instruments	J-FET	1	10 pA	3	14	36	36	0 ~ 70	Active
LM224AN	STMicroelectronics	General Purpose	1.3	20 nA	2	30	3	30	-40 ~ 105	Obsolete
LM224KAN	Texas Instruments	General Purpose	1.2	15 nA	2	30	3	30	-25 ~ 85	Active
LM224KN	Texas Instruments	General Purpose	1.2	20 nA	3	30	3	30	-25 ~ 85	Active

Engineering Selection Recommendations

For Direct Replacement (General Purpose Applications):

KA324A and LM324NE3 provide direct functional equivalence to the LM324NG. Both components maintain identical package format, four-circuit configuration, and compatible supply voltage specifications. KA324A is available in active product status with improved input bias current (40 nA) and lower input offset voltage (1.5 mV). LM324NE3, classified as Last Time Buy from Texas Instruments, offers marginally higher gain bandwidth product (1.2 MHz) and lower input bias current (45 nA) while maintaining ROHS3 compliance.

For Extended Temperature Range Applications:

LM224KAN and LM224KN, both manufactured by Texas Instruments and in active product status, support extended operating temperature ranges (-25°C to 85°C) compared to the LM324NG baseline (0°C to 70°C). These components feature reduced input bias current (15 nA to 20 nA) and maintain general-purpose amplifier classification with four circuits in 14-DIP package format. Maximum supply voltage is limited to 30V, requiring verification against application requirements.

For Ultra-Low Input Bias Current Requirements:

J-FET input amplifiers LF347N/NOPB and LF444CN/NOPB, both in active product status from Texas Instruments, deliver input bias current in the picoampere range (50 pA and 10 pA respectively). These components require symmetric supply voltages (±18V for 36V span or ±22V for 44V span) and are suitable for high-impedance signal conditioning applications. LF444CN/NOPB provides the lowest input bias current (10 pA) but limits output current to 14 mA per channel.

Compliance Considerations:

KA324A, LM324NE3, LM224KAN, LM224KN, LF347N/NOPB, LF444ACN/NOPB, and LF444CN/NOPB all maintain REACH Unaffected status and ROHS3 compliance, suitable for regulated applications. All substitute components are classified under ECCN EAR99 and HTSUS 8542.33.0001, consistent with the original LM324NG classification.

Frequently Asked Questions (FAQ)

Q1: Can the LM324NG be directly replaced with KA324A?

A: Yes. KA324A maintains identical package format (14-DIP), four-circuit configuration, and compatible supply voltage range (3V to 32V). KA324A offers improved electrical characteristics with lower input bias current (40 nA versus 90 nA) and lower input offset voltage (1.5 mV versus 2 mV). Both components operate across 0°C to 70°C temperature range. KA324A is in active product status, addressing the obsolete status of LM324NG.

Q2: What is the primary difference between general-purpose and J-FET input amplifier substitutes?

A: General-purpose amplifiers (KA324A, LM324NE3, LM224 series) feature bipolar input stages with input bias current in the nanoampere range (15 nA to 90 nA). J-FET input amplifiers (LF347, LF444 series) feature field-effect transistor input stages with input bias current in the picoampere range (10 pA to 50 pA), approximately 1000 times lower. J-FET devices require higher supply voltage spans (36V to 44V symmetric supplies) and are optimized for high-impedance signal conditioning. General-purpose devices operate with supply spans as low as 3V to 32V, suitable for single-supply or lower-voltage applications.

Q3: Can J-FET input amplifiers operate with the same supply voltages as the LM324NG?

A: No. The LM324NG operates with supply spans from 3V to 32V. J-FET input amplifiers require symmetric supply voltages: LF347 series requires ±18V (36V span), and LF444 series requires ±22V (44V span). Applications limited to 3V to 32V supply range must use general-purpose amplifier substitutes (KA324A, LM324NE3, LM224 series).

Q4: Which substitute provides the best compatibility for existing designs?

A: LM324NE3 from Texas Instruments provides optimal compatibility. It maintains identical electrical specifications to LM324NG (1 MHz gain bandwidth product, 2 mV input offset voltage, 40 mA output current per channel) while offering improved input bias current (45 nA versus 90 nA). LM324NE3 is classified as Last Time Buy, indicating continued availability during transition periods. All package and mounting specifications remain identical.

Q5: Are all substitute parts RoHS compliant?

A: Yes. All recommended substitute components (KA324A, LM324NE3, LM224KAN, LM224KN, LF347N/NOPB, LF444ACN/NOPB, LF444CN/NOPB) maintain ROHS3 compliance status. The original LM324NG does not specify RoHS status. All substitutes maintain REACH Unaffected classification, consistent with the original component.

Q6: What is the significance of "Last Time Buy" status for LM324NE3?

A: Last Time Buy status indicates that Texas Instruments has announced end-of-life for this component. Customers may place final orders during a specified window before production discontinuation. For new designs, active-status alternatives (KA324A, LM224KAN, LM224KN, LF347N/NOPB, LF444CN/NOPB) are recommended for long-term supply assurance.

Q7: Can LM224 series components replace LM324NG in all applications?

A: LM224 series components are suitable for applications where maximum supply voltage of 30V is acceptable. The LM324NG supports up to 32V supply. LM224 series offers extended operating temperature range (-25°C to 85°C or -40°C to 105°C) compared to LM324NG (0°C to 70°C). Output current per channel is reduced to 30 mA (versus 40 mA for LM324NG). Verification of supply voltage, temperature range, and output current requirements is necessary before substitution.

Q8: What output current limitations apply to J-FET input amplifier substitutes?

A: LF347 series (LF347BN, LF347N, LF347N/NOPB) maintains 40 mA output current per channel, matching LM324NG specifications. LF444 series (LF444ACN/NOPB, LF444CN/NOPB) limits output current to 14 mA per channel. Applications requiring 40 mA output current must use LF347 series if J-FET input characteristics are required. General-purpose amplifiers (KA324A, LM324NE3) maintain 40 mA output current capability.

Q9: How do input offset voltage specifications affect substitution decisions?

A: Input offset voltage determines DC accuracy in precision applications. LM324NG specifies 2 mV input offset voltage. KA324A offers superior performance at 1.5 mV. LM224 series and LF347 series specify 2 mV to 5 mV. LF444 series specifies 2 mV to 3 mV. For applications sensitive to DC offset, KA324A or LF444 series provide improved specifications. For general-purpose applications, all substitutes maintain acceptable offset voltage performance.

Q10: What packaging considerations apply to through-hole mounting?

A: All substitute components maintain 14-DIP through-hole package format with 0.300" (7.62mm) pin spacing, identical to LM324NG. Direct mechanical substitution is possible without PCB redesign. Supplier device packages vary (14-PDIP, 14-MDIP, 14-DIP) but represent equivalent physical formats. Tube packaging is specified for some variants (LM324NE3, LM224KAN, LM224KN, LF347N/NOPB, LF444ACN/NOPB, LF444CN/NOPB), indicating standard reel packaging for automated assembly. Bulk or tape-and-reel packaging availability should be confirmed with suppliers for production requirements.

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