TL084BMD Equivalent & Substitute Parts

Part Overview

The TL084BMD is a J-FET input operational amplifier containing four independent circuits in a 14-SOIC surface mount package, manufactured by STMicroelectronics. This device is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and procurement.

The TL084BMD is qualified to AEC-Q100 automotive standards and operates across an extended temperature range of -40°C to 105°C. Its primary application domain includes automotive-grade analog signal processing requiring low input bias current and moderate bandwidth characteristics.

Due to its obsolete status, alternative components must be evaluated based on electrical performance parameters, package compatibility, and operational temperature specifications to ensure functional equivalence in existing designs.

Key Parameters

Parameter	Value	Unit
Amplifier Type	J-FET	—
Number of Circuits	4	—
Slew Rate	16	V/µs
Gain Bandwidth Product	4	MHz
Current - Input Bias	20	pA
Voltage - Input Offset	1	mV
Current - Supply (per 4 Channels)	1.4	mA
Current - Output per Channel	40	mA
Voltage - Supply Span (Min)	6	V
Voltage - Supply Span (Max)	36	V
Operating Temperature Range	-40 to 105	°C
Package / Case	14-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
Grade	Automotive	—
Qualification	AEC-Q100	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the TL084BMD is determined by the following critical parameters:

Amplifier Architecture: The TL084BMD employs J-FET input topology, which defines its low input bias current characteristic (20 pA). Substitute parts must maintain J-FET input architecture to preserve this performance attribute.

Circuit Count: Four independent operational amplifier circuits are required. All substitute candidates must provide exactly four circuits per package.

Package Compatibility: The 14-SOIC surface mount package with 0.154" (3.90mm) width is the mechanical constraint. Substitute parts must use identical or pin-compatible package geometries.

Electrical Performance Envelope: The TL084BMD operates within a 6V to 36V supply range with a slew rate of 16V/µs and gain bandwidth product of 4 MHz. Substitute parts must support the minimum supply voltage of 6V and accommodate the maximum supply voltage of 36V to ensure functional compatibility.

Operating Temperature: The automotive-grade specification requires operation from -40°C to 105°C. Substitute parts operating only across 0°C to 70°C represent a reduced temperature capability and are suitable only for non-automotive applications or designs not requiring the full extended temperature range.

Compliance and Qualification: RoHS3 compliance and AEC-Q100 qualification are specified attributes. Substitute parts should maintain these certifications for automotive applications.

Parameter Comparison

Parameter	TL084BMD	LF347D	LF347DR	LF444CM/NOPB	LF444CMX/NOPB	LM324AM	LM324AM/NOPB	LM324AMX/NOPB	TL074CD	TL074CDBR	TL074CDG4
Manufacturer	STMicroelectronics	STMicroelectronics	Texas Instruments	Texas Instruments	Texas Instruments	onsemi	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments
Amplifier Type	J-FET	J-FET	J-FET	J-FET	J-FET	General Purpose	General Purpose	General Purpose	J-FET	J-FET	J-FET
Number of Circuits	4	4	4	4	4	4	4	4	4	4	4
Slew Rate (V/µs)	16	16	13	1	1	—	—	—	13	13	13
Gain Bandwidth Product (MHz)	4	3	3	1	1	1	1	1	5.25	5.25	5.25
Current - Input Bias (pA)	20	20	50	10	10	40 nA	45 nA	45 nA	65	65	65
Voltage - Input Offset (mV)	1	3	5	3	3	1.5	2	2	3	3	3
Current - Supply (mA)	1.4	1.4	8	0.6	0.6	1.5	1.5	1.5	1.4	1.4	1.4
Current - Output per Channel (mA)	40	40	40	14	14	40	40	40	—	—	—
Voltage - Supply Span Min (V)	6	44	7	36	36	3	3	3	10	10	10
Voltage - Supply Span Max (V)	36	44	36	36	36	32	32	32	30	30	30
Operating Temperature (°C)	-40 to 105	0 to 70	0 to 70	0 to 70	0 to 70	0 to 70	0 to 70	0 to 70	0 to 70	0 to 70	0 to 70
Package / Case	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SOIC	14-SSOP	14-SOIC
Product Status	Obsolete	Active	Active	Active	Active	Obsolete	Active	Active	Obsolete	Last Time Buy	Obsolete
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes for Automotive Applications

For designs requiring the full automotive temperature range (-40°C to 105°C) with J-FET input characteristics, no direct substitute maintains all original specifications. The TL084BMD's extended temperature capability is not replicated in active production alternatives listed in this reference.

Secondary Substitutes for Commercial Temperature Range (0°C to 70°C)

LF347D and LF347DR maintain J-FET input architecture and four-circuit configuration with compatible 14-SOIC packaging. Both are active products with RoHS3 compliance. LF347DR (Texas Instruments) offers higher inventory availability (105,200 units) compared to LF347D (16,726 units). The LF347 series exhibits a slew rate of 16V/µs matching the TL084BMD, though the gain bandwidth product is reduced to 3 MHz. Supply voltage range for LF347D is limited to 44V fixed operation, while LF347DR supports 7V to 36V, providing better compatibility with the TL084BMD's 6V to 36V specification.

LF444CM/NOPB and LF444CMX/NOPB provide J-FET input topology with four circuits in 14-SOIC packaging and active product status. These devices exhibit significantly reduced slew rate (1V/µs) and gain bandwidth product (1 MHz), representing a substantial performance reduction. Supply voltage is fixed at 36V. These substitutes are suitable only for applications where reduced bandwidth and slew rate are acceptable.

LM324AM/NOPB and LM324AMX/NOPB employ general-purpose amplifier architecture rather than J-FET input, resulting in substantially higher input bias current (45 nanoamperes versus 20 picoamperes). These devices are active products with RoHS3 compliance and support the 3V to 32V supply range. LM324AMX/NOPB offers higher inventory (36,756 units). These substitutes are applicable only to designs where J-FET input characteristics are not critical.

TL074CD and TL074CDG4 provide J-FET input topology with four circuits and 14-SOIC packaging. Both are obsolete products. TL074CD exhibits a slew rate of 13V/µs and gain bandwidth product of 5.25 MHz, with supply voltage range of 10V to 30V. The minimum supply voltage of 10V exceeds the TL084BMD's 6V minimum, restricting applicability to higher-voltage designs.

TL074CDBR is classified as Last Time Buy with a different package format (14-SSOP, 0.209" width) and is not recommended for direct substitution due to package incompatibility with 14-SOIC footprints.

Compliance Considerations

The TL084BMD carries AEC-Q100 automotive qualification. Among the listed substitutes, only LF347D, LF347DR, LF444CM/NOPB, LF444CMX/NOPB, LM324AM/NOPB, and LM324AMX/NOPB maintain RoHS3 compliance. No substitute in this reference maintains AEC-Q100 qualification, which may require design review and validation for automotive applications.

Frequently Asked Questions (FAQ)

Q: Can LF347DR be used as a direct replacement for TL084BMD in automotive applications?

A: LF347DR is not suitable for automotive applications requiring the full -40°C to 105°C temperature range. LF347DR operates only from 0°C to 70°C and lacks AEC-Q100 qualification. However, LF347DR is functionally compatible for commercial temperature range applications, offering J-FET input architecture, four circuits, 14-SOIC packaging, and a slew rate of 16V/µs matching the TL084BMD.

Q: What is the primary difference between J-FET and general-purpose amplifier types?

A: J-FET input amplifiers, such as the TL084BMD and LF347 series, exhibit extremely low input bias current (typically in the picoampere range). General-purpose amplifiers, such as the LM324 series, exhibit significantly higher input bias current (typically in the nanoampere range). This distinction is critical in applications requiring high input impedance or minimal input current draw.

Q: Why does LF347D specify a fixed 44V supply voltage while LF347DR supports 7V to 36V?

A: These are distinct product variants from different manufacturers. LF347D (STMicroelectronics) and LF347DR (Texas Instruments) share the same base product number but differ in electrical specifications and manufacturing source. Design selection should verify supply voltage compatibility with the specific variant chosen.

Q: Is the 14-SSOP package used by TL074CDBR compatible with 14-SOIC footprints?

A: No. The 14-SSOP package (0.209" width) is not compatible with 14-SOIC footprints (0.154" width). These packages have different pin pitch and body dimensions. TL074CDBR requires a distinct PCB footprint and is not suitable for direct substitution in designs using 14-SOIC land patterns.

Q: Can LM324AM/NOPB replace TL084BMD in low-frequency signal conditioning applications?

A: LM324AM/NOPB can replace TL084BMD in applications where J-FET input characteristics are not essential. However, the substantially higher input bias current (45 nanoamperes versus 20 picoamperes) may introduce measurement errors in high-impedance signal sources. The general-purpose amplifier architecture is suitable for applications with input impedances below 1 megohm and where input current leakage is not a limiting factor.

Q: What is the significance of the "Last Time Buy" status for TL074CDBR?

A: Last Time Buy status indicates that the manufacturer has announced end-of-life for this product. Existing inventory may be available for a limited period, but no future production is planned. This status makes TL074CDBR unsuitable for new designs or long-term production requirements.

Q: How does the reduced slew rate of LF444 series (1V/µs) affect circuit performance compared to TL084BMD (16V/µs)?

A: Slew rate determines the maximum rate of change of output voltage. A slew rate of 1V/µs limits the maximum output voltage change to 1 volt per microsecond, while 16V/µs permits 16 times faster transitions. In applications requiring high-speed signal processing or driving capacitive loads, the reduced slew rate of LF444 series may introduce distortion or limit bandwidth. LF444 series is suitable for low-frequency applications where slew rate is not a performance constraint.

Q: Are all listed substitutes RoHS3 compliant?

A: No. LM324AM (onsemi) does not specify RoHS status in the provided data. All other substitutes listed are RoHS3 compliant. Design requirements for RoHS compliance should be verified against the specific substitute part selected.

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