KA324 Equivalent & Substitute Parts

Part Overview

The KA324 is a general-purpose operational amplifier integrated circuit containing four independent amplifier circuits in a 14-pin DIP package. Manufactured by onsemi, this device operates across a supply voltage range of 3V to 32V and is designed for through-hole mounting applications. The KA324 is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and production requirements. Substitute parts must maintain functional compatibility while accommodating modern packaging and availability constraints.

Key Parameters

Parameter	Value	Unit
Amplifier Type	General Purpose	—
Number of Circuits	4	—
Current - Input Bias	40	nA
Voltage - Input Offset	1.5	mV
Current - Supply	1	mA
Current - Output / Channel	40	mA
Voltage - Supply Span (Min)	3	V
Voltage - Supply Span (Max)	32	V
Operating Temperature	0 to 70	°C
Mounting Type	Through Hole	—
Package / Case	14-DIP (0.300", 7.62mm)	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the KA324 is determined by the following critical parameters:

Primary Substitution Criteria:

Amplifier Type: General Purpose (matches LM324 series variants)
Number of Circuits: 4 independent amplifier channels
Supply Voltage Range: Minimum 3V, Maximum 32V (or compatible subset)
Current - Output / Channel: 40 mA capability
Operating Temperature Range: 0°C to 70°C (or extended range)
Package Compatibility: 14-DIP through-hole mounting

Substitution Categories:

Direct Package Equivalents (14-DIP Through-Hole): Parts maintaining identical 14-DIP form factor with general-purpose amplifier topology. These include LM224 series variants and LM324 series through-hole packages.
Surface Mount Alternatives (14-SOIC): The LM324DR2G provides functional equivalence with surface-mount packaging, suitable for designs transitioning to SMD assembly.
J-FET Input Variants (14-DIP Through-Hole): LF347 and LF444 series provide alternative input stage topologies with different electrical characteristics, including lower input bias current and higher supply voltage requirements.

Substitutes are grouped by mounting type and amplifier topology, as these parameters determine physical and electrical compatibility within the application circuit.

Parameter Comparison

Part Number	Manufacturer	Amplifier Type	Number of Circuits	Input Bias (nA)	Input Offset (mV)	Supply Min (V)	Supply Max (V)	Output / Channel (mA)	Mounting Type	Package	Product Status
KA324	onsemi	General Purpose	4	40	1.5	3	32	40	Through Hole	14-DIP	Obsolete
LM324DR2G	onsemi	General Purpose	4	90	2	3	32	40	Surface Mount	14-SOIC	Active
LF347BN	onsemi	J-FET	4	0.05	3	36	36	40	Through Hole	14-DIP	Obsolete
LF347N	STMicroelectronics	J-FET	4	0.02	3	44	44	40	Through Hole	14-DIP	Obsolete
LF347N/NOPB	Texas Instruments	J-FET	4	0.05	5	36	36	40	Through Hole	14-DIP	Active
LF444ACN/NOPB	Texas Instruments	J-FET	4	0.01	2	44	44	14	Through Hole	14-DIP	Active
LF444CN/NOPB	Texas Instruments	J-FET	4	0.01	3	36	36	14	Through Hole	14-DIP	Active
LM224AN	STMicroelectronics	General Purpose	4	20	2	3	30	30	Through Hole	14-DIP	Obsolete
LM224KAN	Texas Instruments	General Purpose	4	15	2	3	30	30	Through Hole	14-DIP	Active
LM224KN	Texas Instruments	General Purpose	4	20	3	3	30	30	Through Hole	14-DIP	Active
LM224N	STMicroelectronics	General Purpose	4	20	2	3	30	40	Through Hole	14-DIP	Obsolete

Engineering Selection Recommendations

For Direct Replacement (Through-Hole 14-DIP, General Purpose):

The LM224 series (LM224KAN, LM224KN) provides the closest functional equivalence to the KA324 with active product status. Both parts maintain 14-DIP through-hole packaging, four-circuit configuration, and general-purpose amplifier topology. The LM224KAN and LM224KN are manufactured by Texas Instruments and carry ROHS3 compliance certification. These parts operate within the 3V to 30V supply range, which encompasses the KA324 operating window. The maximum supply voltage of 30V is within the KA324 specification of 32V maximum.

For Surface Mount Transition:

The LM324DR2G (onsemi, 14-SOIC) is an active product offering functional equivalence with surface-mount packaging. This part maintains the 3V to 32V supply range and 40 mA output current per channel. The LM324DR2G is suitable for designs transitioning from through-hole to surface-mount assembly.

For Low Input Bias Current Applications:

The LF347N/NOPB (Texas Instruments, active status) and LF444CN/NOPB (Texas Instruments, active status) provide J-FET input stages with significantly lower input bias current (0.05 nA and 0.01 nA respectively). These parts require fixed ±36V or ±44V dual supply operation and are not suitable for single-supply applications. The LF444CN/NOPB provides the lowest input bias current (0.01 nA) but limits output current to 14 mA per channel.

Compliance and Certification:

All recommended active substitutes carry ROHS3 compliance and REACH unaffected status, matching the KA324 regulatory profile. Moisture sensitivity level is 1 (Unlimited) for all recommended parts.

Frequently Asked Questions (FAQ)

Q: Can the LM224 series directly replace the KA324 in existing through-hole PCB designs?

A: Yes. The LM224KAN and LM224KN maintain identical 14-DIP through-hole packaging and pin configuration. Both are four-circuit general-purpose amplifiers with compatible supply voltage ranges (3V to 30V). Existing PCB layouts require no modification. Verify that your application does not require the KA324 maximum supply voltage of 32V, as LM224 variants are rated to 30V maximum.

Q: What is the difference between LM224KAN and LM224KN?

A: Both parts are manufactured by Texas Instruments in 14-DIP through-hole packaging with active product status. The LM224KAN specifies input bias current of 15 nA, while the LM224KN specifies 20 nA. The LM224KAN specifies input offset voltage of 2 mV, while the LM224KN specifies 3 mV. Both parts operate across 3V to 30V supply range and deliver 30 mA output current per channel. Selection between these variants depends on application tolerance requirements for input bias and offset specifications.

Q: Why would I select an LF347 or LF444 variant instead of an LM224?

A: LF347 and LF444 variants employ J-FET input stages, resulting in dramatically lower input bias current (0.02 nA to 0.05 nA versus 15 to 20 nA for LM224). These characteristics are essential for high-impedance signal conditioning, precision instrumentation, and applications where input bias current introduces unacceptable error. However, J-FET variants require dual supply operation (±36V or ±44V) and are not compatible with single-supply circuits. Additionally, LF444 variants limit output current to 14 mA per channel, compared to 30 to 40 mA for general-purpose types.

Q: Is the LM324DR2G suitable for my through-hole PCB design?

A: No. The LM324DR2G is a surface-mount device in 14-SOIC packaging. This part is suitable only for designs using surface-mount assembly processes. Through-hole PCB designs require through-hole mounted components such as LM224 variants or LF347/LF444 series.

Q: What are the supply voltage constraints when substituting the KA324?

A: The KA324 operates across 3V to 32V. The LM224 series operates across 3V to 30V, which is compatible for applications not requiring the full 32V maximum. The LF347 and LF444 series require fixed dual supply operation at ±36V or ±44V and are not compatible with single-supply applications. Verify your circuit design operates within the substitute part's specified supply voltage range.

Q: Are all recommended substitutes RoHS3 compliant?

A: Yes. All active substitute parts (LM224KAN, LM224KN, LM324DR2G, LF347N/NOPB, LF444ACN/NOPB, LF444CN/NOPB) carry ROHS3 compliance certification, matching the KA324 regulatory status. All parts are REACH unaffected.

Q: What is the difference between LF444ACN/NOPB and LF444CN/NOPB?

A: Both parts are J-FET input amplifiers in 14-DIP through-hole packaging manufactured by Texas Instruments with active product status. The LF444ACN/NOPB specifies a supply voltage range of ±44V (44V minimum and maximum), while the LF444CN/NOPB specifies ±36V (36V minimum and maximum). Both deliver identical electrical performance: 0.01 nA input bias current, 1 MHz gain bandwidth product, and 14 mA output current per channel. Selection depends on available dual supply voltage in your application.

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