LM224KD Equivalent & Substitute Parts

Part Overview

The LM224KD is a general-purpose operational amplifier integrated circuit manufactured by Texas Instruments, configured as a 4-circuit device in 14-SOIC surface mount packaging. This part is classified as obsolete, indicating discontinued production and limited availability for new designs. The LM224KD operates across a wide supply voltage range of 3V to 30V and is suitable for general analog signal processing applications requiring moderate bandwidth and slew rate performance.

Due to its obsolete status, identifying functionally equivalent substitute parts is necessary for design continuity, procurement flexibility, and long-term supply chain reliability. Substitute parts must maintain compatibility across key electrical parameters including supply voltage range, circuit count, output current capability, and package form factor.

Key Parameters

Parameter	LM224KD Value	Unit	Substitution Relevance
Amplifier Type	General Purpose	—	Critical
Number of Circuits	4	Channels	Critical
Package / Case	14-SOIC (0.154", 3.90mm Width)	—	Critical
Mounting Type	Surface Mount	—	Critical
Voltage - Supply Span (Min)	3	V	Critical
Voltage - Supply Span (Max)	30	V	Critical
Gain Bandwidth Product	1.2	MHz	Important
Slew Rate	0.5	V/µs	Important
Current - Output / Channel	30	mA	Important
Current - Input Bias	20	nA	Important
Voltage - Input Offset	3	mV	Important
Current - Supply	1.4	mA (x4 Channels)	Important
Operating Temperature	-25°C ~ 85°C	—	Important
RoHS Status	ROHS3 Compliant	—	Important
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—	Important

Substitute Part Grouping Explanation

Substitution of the LM224KD is determined by strict adherence to the following critical parameters:

Critical Parameters (Must Match or Exceed):

Number of Circuits: 4 channels required
Package / Case: 14-SOIC form factor with 0.154" (3.90mm) width
Mounting Type: Surface mount configuration
Voltage - Supply Span: Minimum 3V and maximum supply voltage of at least 30V

Important Parameters (Should Match or Exceed):

Gain Bandwidth Product: 1.2 MHz or higher
Slew Rate: 0.5 V/µs or higher
Current - Output / Channel: 30 mA or higher
Current - Input Bias: 20 nA or lower
Voltage - Input Offset: 3 mV or lower
Operating Temperature Range: Should cover -25°C to 85°C minimum
Compliance: ROHS3 and MSL Level 1

Substitute parts are grouped into two categories:

Category A - Direct Substitutes (Active Status): Parts with identical or superior electrical performance, active product status, and confirmed compatibility across all critical and important parameters.

Category B - Functional Equivalents (Obsolete Status): Parts with comparable electrical performance and package compatibility but potentially different manufacturers or slightly modified specifications.

Parameter Comparison

Part Number	Manufacturer	Product Status	Circuits	Package	GBW (MHz)	Slew Rate (V/µs)	Output Current (mA)	Input Bias (nA)	Input Offset (mV)	Supply Min (V)	Supply Max (V)	Temp Range (°C)
LM224KD	Texas Instruments	Obsolete	4	14-SOIC	1.2	0.5	30	20	3	3	30	-25 ~ 85
LM2902DR	Rohm Semiconductor	Obsolete	4	14-SOIC	1.2	0.3	30	20	1	3	32	-40 ~ 125
LM324AM/NOPB	Texas Instruments	Active	4	14-SOIC	1	—	40	45	2	3	32	0 ~ 70
LM324AMX/NOPB	Texas Instruments	Active	4	14-SOIC	1	—	40	45	2	3	32	0 ~ 70
LM324M/NOPB	Texas Instruments	Active	4	14-SOIC	1	—	40	45	2	3	32	0 ~ 70
LM324MX/NOPB	Texas Instruments	Active	4	14-SOIC	1	—	40	45	2	3	32	0 ~ 70
LP324M/NOPB	Texas Instruments	Active	4	14-SOIC	0.1	0.05	10	2	2	3	32	0 ~ 70
LP324MX/NOPB	Texas Instruments	Active	4	14-SOIC	0.1	0.05	10	2	2	3	32	0 ~ 70
LM224DR2G	onsemi	Active	4	14-SOIC	1	—	40	90	2	3	32	-25 ~ 85
BA10324AF-E2	Rohm Semiconductor	Active	4	14-SOP	0.5	0.2	35	20	2	3	32	-40 ~ 85
BA2902F-E2	Rohm Semiconductor	Active	4	14-SOP	0.5	0.2	30	20	2	3	32	-40 ~ 125

Engineering Selection Recommendations

Primary Substitute (Active Status, Highest Compatibility):

The LM324AMX/NOPB and LM324MX/NOPB from Texas Instruments are recommended as primary substitutes for the obsolete LM224KD. Both parts maintain the same manufacturer lineage, identical 14-SOIC package geometry, 4-circuit configuration, and supply voltage compatibility (3V to 32V). These parts carry active product status, ensuring long-term availability and supply chain stability. Both are ROHS3 compliant with MSL Level 1 rating. The LM324 series represents the modern evolution of the LM224 architecture with enhanced output current capability (40 mA vs. 30 mA per channel). The primary trade-off is a reduced operating temperature range (0°C to 70°C versus -25°C to 85°C) and lower gain-bandwidth product (1 MHz versus 1.2 MHz), which are acceptable for most general-purpose applications not requiring extended temperature operation.

Secondary Substitute (Active Status, Extended Temperature):

The LM224DR2G from onsemi provides active product status with the original LM224 base part number and maintains the critical -25°C to 85°C operating temperature range of the original LM224KD. This part is packaged in 14-SOIC format with 4 circuits and supports 3V to 32V supply operation. It offers 40 mA output current per channel and 1 MHz gain-bandwidth product. Input bias current is higher at 90 nA compared to the original 20 nA specification. This substitute is suitable for applications requiring the extended temperature range of the original part.

Alternative Substitute (Active Status, Low-Power Applications):

The LP324M/NOPB and LP324MX/NOPB from Texas Instruments are suitable for applications where power consumption is a primary concern. These low-power variants operate at 85 µA supply current (versus 1.4 mA for the original) and provide 10 mA output current per channel. The gain-bandwidth product is reduced to 100 kHz and slew rate to 0.05 V/µs. These parts are appropriate only for applications that do not require the bandwidth and slew rate performance of the original LM224KD.

Package Variant Substitutes (Active Status, Different Package):

The BA10324AF-E2 and BA2902F-E2 from Rohm Semiconductor are available in 14-SOP package (0.173" width versus 0.154" for SOIC). These parts maintain 4-circuit configuration and 3V to 32V supply compatibility but require PCB layout modification due to different package dimensions. Both are active products with ROHS3 compliance. The BA10324AF-E2 operates -40°C to 85°C, while BA2902F-E2 extends to -40°C to 125°C.

Obsolete Substitute (Reference Only):

The LM2902DR from Rohm Semiconductor is classified as obsolete but provides functional equivalence with 1.2 MHz gain-bandwidth product, 14-SOIC package, and extended temperature range (-40°C to 125°C). This part should be considered only when active alternatives are unavailable and supply can be confirmed.

Frequently Asked Questions (FAQ)

Q1: Can I directly replace LM224KD with LM324AMX/NOPB without PCB modifications?

A: Yes. Both parts use identical 14-SOIC packaging with 0.154" (3.90mm) width, 4-circuit configuration, and pin-compatible layouts. No PCB layout changes are required. However, verify that your application can tolerate the reduced operating temperature range (0°C to 70°C for LM324 versus -25°C to 85°C for LM224KD) and the lower gain-bandwidth product (1 MHz versus 1.2 MHz).

Q2: What is the key difference between LM324 and LP324 series?

A: The LP324 series is optimized for low-power applications with 85 µA supply current and 100 kHz gain-bandwidth product, compared to the LM324 at 1.5 mA supply current and 1 MHz bandwidth. The LP324 provides only 10 mA output current per channel versus 40 mA for LM324. Select LP324 only if your application has strict power consumption requirements and does not need the performance of the original LM224KD.

Q3: Why does LM224DR2G from onsemi show higher input bias current (90 nA) than the original LM224KD (20 nA)?

A: The LM224DR2G represents a different manufacturing variant or process node from onsemi. While the base part number is LM224, the actual electrical characteristics differ from the original Texas Instruments LM224KD. This higher input bias current may affect precision analog circuits with high-impedance inputs. Verify circuit tolerance before substitution.

Q4: Can I use BA10324AF-E2 or BA2902F-E2 as direct substitutes?

A: These Rohm Semiconductor parts are functionally equivalent but use 14-SOP packaging (0.173" width) instead of 14-SOIC (0.154" width). PCB layout modifications are required, including different pad spacing and potentially different trace routing. Pin assignments are compatible, but physical footprint changes necessitate design review. These substitutes are suitable only when PCB redesign is acceptable.

Q5: Which substitute should I select for applications requiring -25°C to 85°C operation?

A: The LM224DR2G from onsemi is the only active substitute that maintains the original -25°C to 85°C operating temperature range. The LM324 series is limited to 0°C to 70°C. If extended temperature operation is critical, LM224DR2G is the appropriate choice, accepting the trade-off of higher input bias current (90 nA versus 20 nA).

Q6: Are all recommended substitutes ROHS3 compliant?

A: Yes. All substitute parts listed carry ROHS3 compliance certification and MSL Level 1 (Unlimited) moisture sensitivity rating, matching the original LM224KD specifications. This ensures compatibility with modern manufacturing processes and environmental regulations.

Q7: What is the impact of reduced slew rate in LM2902DR (0.3 V/µs) compared to LM224KD (0.5 V/µs)?

A: Slew rate determines the maximum rate of voltage change the amplifier can produce. A lower slew rate may cause signal distortion in high-frequency or high-amplitude applications. For general-purpose applications with moderate signal frequencies and amplitudes, the difference is typically not significant. Verify slew rate requirements in your specific circuit design before substitution.

Q8: Can I mix different substitute parts in the same design?

A: Not recommended. While all substitutes are functionally equivalent at the system level, they have different electrical characteristics (input bias current, slew rate, bandwidth, output current). Using different parts in parallel or in the same circuit may cause performance inconsistencies, offset errors, or stability issues. Standardize on a single substitute part number across the entire design.

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