LM348MX Equivalent & Substitute Parts

Part Overview

The LM348MX is a general-purpose operational amplifier featuring four independent circuits in a 14-SOIC surface mount package, manufactured by Texas Instruments. This device is classified as obsolete and is no longer in active production. The LM348MX operates across a supply voltage range of 36 V with a slew rate of 0.5 V/µs and a gain bandwidth product of 1 MHz, making it suitable for general analog signal processing applications requiring moderate bandwidth and low input bias current.

Due to its obsolete status, sourcing new units from the original manufacturer is no longer feasible. Equivalent and substitute parts must be identified based on matching electrical characteristics, package compatibility, and functional performance parameters to ensure seamless integration into existing designs or new production runs.

Key Parameters

Parameter	LM348MX Value	Unit
Amplifier Type	General Purpose	—
Number of Circuits	4	—
Slew Rate	0.5	V/µs
Gain Bandwidth Product	1	MHz
Current - Input Bias	30	nA
Voltage - Input Offset	1	mV
Current - Supply (x4 Channels)	2.4	mA
Current - Output / Channel	25	mA
Voltage - Supply Span	36	V
Operating Temperature	0 to 70	°C
Mounting Type	Surface Mount	—
Package / Case	14-SOIC (0.154", 3.90mm Width)	—
RoHS Status	RoHS non-compliant	—

Substitute Part Grouping Explanation

Substitution of the LM348MX is determined by strict alignment of the following critical parameters:

Primary Substitution Criteria:

Amplifier Type: General Purpose
Number of Circuits: 4
Package / Case: 14-SOIC surface mount configuration
Slew Rate: 0.5 V/µs (minimum acceptable)
Gain Bandwidth Product: 1 MHz (minimum acceptable)
Current - Input Bias: 30 nA (maximum acceptable)
Voltage - Input Offset: 1 mV (maximum acceptable)
Current - Output / Channel: 25 mA (minimum acceptable)
Voltage - Supply Span: 36 V (minimum acceptable)
Operating Temperature: 0°C to 70°C (minimum acceptable range)

Substitute parts are grouped into two categories:

Category 1: Direct Electrical Equivalents (Same Amplifier Type) Parts that maintain identical or superior electrical performance within the general-purpose amplifier classification, with matching or compatible supply voltage specifications and package dimensions.

Category 2: Enhanced Performance Alternatives (Different Amplifier Type) Parts that exceed the electrical specifications of the LM348MX through alternative amplifier topologies (such as J-FET input stages), offering superior slew rate, bandwidth, and input bias current characteristics while maintaining the four-circuit configuration and 14-SOIC package format.

Parameter Comparison

Part Number	Manufacturer	Amplifier Type	Slew Rate (V/µs)	GBW (MHz)	Input Bias (nA)	Input Offset (mV)	Supply Span (V)	Output Current (mA)	Temp Range (°C)	Status
LM348MX	Texas Instruments	General Purpose	0.5	1	30	1	36	25	0 to 70	Obsolete
LM348D	onsemi	General Purpose	0.5	1	30	1	8 to 36	25	0 to 70	Obsolete
LM348DR	Texas Instruments	General Purpose	0.5	1	30	1	8 to 36	25	0 to 70	Active
LM348NSR	Texas Instruments	General Purpose	0.5	1	30	1	8 to 36	25	0 to 70	Last Time Buy
LF247DT	STMicroelectronics	J-FET	16	4	0.02	3	44	40	-40 to 105	Active
LF347D	STMicroelectronics	J-FET	16	3	0.02	3	44	40	0 to 70	Active
LF347DT	STMicroelectronics	J-FET	16	4	0.02	3	44	40	0 to 70	Active
LM124DT	STMicroelectronics	General Purpose	0.4	1.3	20	2	3 to 30	40	-55 to 125	Active
LM248DT	STMicroelectronics	General Purpose	0.5	1.3	30	1	44	25	-40 to 105	Active
LM2902D	onsemi	General Purpose	0.5	1.2	20	3	3 to 26	30	-40 to 125	Obsolete
LM324ADT	STMicroelectronics	General Purpose	0.4	1.3	20	2	3 to 30	40	0 to 70	Active

Engineering Selection Recommendations

Primary Recommendation: LM348DR (Texas Instruments)

The LM348DR is the manufacturer-recommended direct replacement for the LM348MX. This part maintains identical electrical specifications including slew rate, gain bandwidth product, input bias current, and input offset voltage. The LM348DR is currently in active production status with ROHS3 compliance certification, ensuring long-term availability and regulatory alignment. Supply voltage range extends from 8 V to 36 V, providing greater flexibility than the original LM348MX specification. Packaging is available in Cut Tape and Digi-Reel formats with 23,947 units currently in stock.

Secondary Recommendation: LM348NSR (Texas Instruments)

The LM348NSR provides identical electrical performance to the LM348MX with the same supply voltage range (8 V to 36 V) and operating temperature specification (0°C to 70°C). This part carries Last Time Buy status, indicating limited future availability. ROHS3 compliance is certified. The 14-SO package (0.209", 5.30mm width) differs slightly from the LM348MX 14-SOIC package (0.154", 3.90mm width), requiring PCB layout verification before implementation.

Alternative for Enhanced Performance: LF347DT (STMicroelectronics)

The LF347DT offers superior electrical performance through J-FET input stage technology, delivering 16 V/µs slew rate (32× improvement), 4 MHz gain bandwidth product (4× improvement), and 0.02 nA input bias current (1500× improvement) compared to the LM348MX. This part is in active production with ROHS3 compliance. Operating temperature range extends to 0°C to 70°C. The higher supply voltage span (44 V) accommodates broader application requirements. Selection of this part requires circuit redesign validation due to significantly different electrical characteristics.

Alternative for Extended Temperature Range: LM124DT (STMicroelectronics)

The LM124DT maintains general-purpose amplifier classification with four circuits in 14-SOIC package. This part is in active production with ROHS3 compliance and extended operating temperature range (-55°C to 125°C). Supply voltage range is 3 V to 30 V. Slew rate is 0.4 V/µs and gain bandwidth product is 1.3 MHz, both compatible with LM348MX applications. Input bias current is 20 nA and input offset voltage is 2 mV, both superior to the original specification.

Compliance Consideration:

The LM348MX is RoHS non-compliant. All recommended active production alternatives (LM348DR, LF347DT, LM124DT, LM324ADT) carry ROHS3 compliance certification, meeting current regulatory requirements for new designs and production runs.

Frequently Asked Questions (FAQ)

Q1: Can the LM348DR be used as a direct drop-in replacement for the LM348MX?

A: Yes. The LM348DR maintains identical electrical specifications for slew rate (0.5 V/µs), gain bandwidth product (1 MHz), input bias current (30 nA), input offset voltage (1 mV), and output current per channel (25 mA). Both parts use the 14-SOIC surface mount package with identical pinout. The LM348DR supply voltage range (8 V to 36 V) encompasses the LM348MX specification (36 V). No circuit modifications are required.

Q2: What is the difference between LM348DR and LM348NSR?

A: Both parts provide identical electrical performance and are manufactured by Texas Instruments. The primary difference is packaging format: LM348DR is supplied in Cut Tape and Digi-Reel format, while LM348NSR is supplied in Tape & Reel format. Additionally, LM348NSR uses a 14-SO package (0.209", 5.30mm width) compared to LM348DR's 14-SOIC package (0.154", 3.90mm width). This package dimension difference requires PCB layout verification. LM348NSR carries Last Time Buy status, indicating limited future availability.

Q3: Why would I select LF347DT instead of LM348DR?

A: Selection of LF347DT is appropriate when application requirements demand superior dynamic performance. The LF347DT delivers 32× faster slew rate (16 V/µs versus 0.5 V/µs), 4× higher gain bandwidth product (4 MHz versus 1 MHz), and 1500× lower input bias current (0.02 nA versus 30 nA). These improvements enable faster signal processing, reduced input offset errors, and enhanced noise performance. However, the LF347DT uses J-FET input stage technology, which introduces different input impedance characteristics and requires circuit redesign validation. The higher supply voltage span (44 V) also differs from the LM348MX specification.

Q4: Is the LM348D a suitable substitute?

A: The LM348D, manufactured by onsemi, provides identical electrical specifications to the LM348MX with matching slew rate, gain bandwidth product, input bias current, and input offset voltage. However, the LM348D is classified as obsolete, making it unsuitable for new production runs or long-term sourcing. The LM348D supply voltage range (8 V to 36 V) is superior to the LM348MX specification. For new designs, the active production LM348DR is the preferred choice.

Q5: Can I use LM124DT or LM324ADT in place of LM348MX?

A: LM124DT and LM324ADT are functionally compatible general-purpose four-circuit operational amplifiers in 14-SOIC packages. Both parts are in active production with ROHS3 compliance. However, both parts have reduced supply voltage range (3 V to 30 V) compared to the LM348MX specification (36 V). If your application operates within the 3 V to 30 V range, these parts are suitable alternatives. LM124DT offers extended temperature range (-55°C to 125°C), while LM324ADT operates at 0°C to 70°C, matching the LM348MX specification. Slew rate and gain bandwidth product are comparable or superior to the LM348MX.

Q6: What does "Last Time Buy" status mean for LM348NSR?

A: Last Time Buy status indicates that the manufacturer has announced the end of production for this part number. Existing inventory will be sold until depletion, after which the part will no longer be available from the manufacturer. For applications requiring long-term component availability, the active production LM348DR is the recommended choice. If LM348NSR is selected, procurement should occur immediately to secure adequate stock before availability ends.

Q7: Are there package compatibility issues between substitute parts?

A: Most substitute parts use the 14-SOIC package (0.154", 3.90mm width), which is directly compatible with the LM348MX. The exception is LM348NSR, which uses a 14-SO package (0.209", 5.30mm width). This dimension difference requires PCB layout verification, as the wider package may not fit existing PCB footprints designed for the narrower 14-SOIC format. All other recommended substitutes maintain the 14-SOIC package specification and are mechanically compatible.

Q8: What is the significance of RoHS compliance for substitute selection?

A: The LM348MX is RoHS non-compliant, reflecting its obsolete status and pre-RoHS manufacturing era. All recommended active production alternatives (LM348DR, LF347DT, LM124DT, LM324ADT) carry ROHS3 compliance certification. For new product designs or manufacturing in regions with RoHS regulatory requirements, selection of ROHS3-compliant parts is mandatory. Existing designs using the LM348MX may continue operation without RoHS compliance, but new production runs should transition to compliant alternatives.

Q9: How do I verify that a substitute part will work in my existing circuit?

A: Verification requires comparison of critical electrical parameters: slew rate, gain bandwidth product, input bias current, input offset voltage, output current capability, and supply voltage range. Cross-reference your circuit schematic against the Parameter Comparison table provided in this document. Ensure that the substitute part's specifications meet or exceed the minimum requirements of your application. For parts with significantly different characteristics (such as J-FET alternatives), circuit simulation or prototype testing is recommended before full production implementation.

Q10: Which substitute part offers the best long-term availability?

A: The LM348DR, manufactured by Texas Instruments, offers the best long-term availability. This part is in active production status with 23,947 units currently in stock. Texas Instruments maintains extensive distribution networks and production capacity for this part number. The LM348DR is the manufacturer-recommended replacement for the obsolete LM348MX, ensuring continued support and availability for future procurement cycles.

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