AD746JR Equivalent & Substitute Parts

Part Overview

The AD746JR is a J-FET input operational amplifier manufactured by Analog Devices Inc., configured as a dual-channel (2 circuit) device in an 8-SOIC surface mount package. This component is classified as obsolete, indicating that direct procurement of the AD746JR may face availability constraints. The part delivers high input impedance characteristics typical of J-FET amplifiers with a slew rate of 75V/µs and gain bandwidth product of 13 MHz, suitable for precision signal conditioning and low-noise amplification applications. Identification of equivalent and substitute parts is necessary to ensure design continuity and maintain supply chain reliability for legacy and new production requirements.

Key Parameters

Parameter	Value	Unit
Amplifier Type	J-FET	—
Number of Circuits	2	—
Slew Rate	75	V/µs
Gain Bandwidth Product	13	MHz
-3dB Bandwidth	13	MHz
Current - Input Bias	110	pA
Voltage - Input Offset	300	µV
Current - Supply	7	mA
Current - Output / Channel	25	mA
Voltage - Supply Span (Min)	9	V
Voltage - Supply Span (Max)	36	V
Operating Temperature	0 to 70	°C
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the AD746JR is determined by strict alignment of electrical and mechanical parameters. The primary substitution criteria are:

Direct Equivalent Category: Parts that maintain identical amplifier type (J-FET), circuit count (2), package format (8-SOIC), and operating temperature range (0°C to 70°C). The AD746JRZ qualifies as a direct equivalent, differing only in product status (Active vs. Obsolete) and packaging format (Tube vs. unspecified).

Functional Substitute Category: Parts that share the same package footprint (8-SOIC), dual-channel configuration, and surface mount mounting type, but differ in amplifier topology or performance characteristics. The LT2178 series (LT2178ACS8#PBF, LT2178ACS8#TRPBF, LT2178AIS8#PBF, LT2178AIS8#TR, LT2178AIS8#TRPBF, and LT2178IS8#PBF, LT2178IS8#TRPBF) and LF353DT represent functional alternatives with general-purpose or J-FET topologies respectively. These parts accommodate the same supply voltage range (9V to 36V minimum/maximum overlap) and operate within compatible temperature bands.

Extended Substitute Category: Parts including LF253DT that maintain J-FET amplifier type and dual-channel configuration in 8-SOIC packaging but exhibit different performance metrics (slew rate, bandwidth, input bias current) and extended operating temperature ranges (-40°C to 105°C).

Substitution logic is based strictly on the following parameters: amplifier type, number of circuits, package/case format, mounting type, supply voltage compatibility, and operating temperature range overlap.

Parameter Comparison

Part Number	Manufacturer	Amplifier Type	Number of Circuits	Slew Rate (V/µs)	Gain Bandwidth Product (MHz)	Input Bias Current (pA)	Input Offset Voltage (µV)	Supply Current (mA)	Output Current / Channel (mA)	Supply Voltage Min (V)	Supply Voltage Max (V)	Operating Temperature (°C)	Package	Product Status
AD746JR	Analog Devices Inc.	J-FET	2	75	13	110	300	7	25	9	36	0 to 70	8-SOIC	Obsolete
AD746JRZ	Analog Devices Inc.	J-FET	2	75	13	110	300	7	25	9	36	0 to 70	8-SOIC	Active
LT2178ACS8#PBF	Analog Devices Inc.	General Purpose	2	0.04	0.085	3	70	0.016	—	2.2	36	0 to 70	8-SOIC	Active
LT2178ACS8#TRPBF	Analog Devices Inc.	General Purpose	2	0.04	0.085	3	70	0.016	—	2.2	36	0 to 70	8-SOIC	Active
LT2178AIS8#PBF	Analog Devices Inc.	General Purpose	2	0.04	0.085	3	70	0.016	—	2.2	36	-40 to 85	8-SOIC	Active
LT2178AIS8#TR	Analog Devices Inc.	General Purpose	2	0.04	0.085	3	70	0.016	—	2.2	36	-40 to 85	8-SOIC	Active
LT2178AIS8#TRPBF	Analog Devices Inc.	General Purpose	2	0.04	0.085	3	70	0.016	—	2.2	36	-40 to 85	8-SOIC	Active
LT2178IS8#PBF	Analog Devices Inc.	General Purpose	2	0.04	0.085	3	90	0.017	—	2.2	36	-40 to 85	8-SOIC	Active
LT2178IS8#TRPBF	Analog Devices Inc.	General Purpose	2	0.04	0.085	3	90	0.017	—	2.2	36	-40 to 85	8-SOIC	Active
LF253DT	STMicroelectronics	J-FET	2	16	4	20	3000	1.4	40	6	36	-40 to 105	8-SOIC	Active
LF353DT	STMicroelectronics	J-FET	2	16	4	20	3000	1.4	40	6	36	0 to 70	8-SOIC	Active

Engineering Selection Recommendations

Direct Replacement: The AD746JRZ is the primary recommended substitute for the obsolete AD746JR. Both parts are manufactured by Analog Devices Inc. and share identical electrical specifications, circuit configuration, and package format. The AD746JRZ maintains Active product status, ensuring long-term availability and supply chain continuity. The only distinction is packaging format (Tube for AD746JRZ versus unspecified for AD746JR), which does not affect electrical performance or PCB integration.

J-FET Topology Alternatives: The LF253DT and LF353DT from STMicroelectronics maintain J-FET amplifier architecture and dual-channel configuration in 8-SOIC packaging. Both parts are RoHS3 compliant and REACH unaffected. The LF353DT operates within the identical temperature range (0°C to 70°C) as the AD746JR, making it suitable for applications with matching thermal requirements. The LF253DT extends the operating range to -40°C to 105°C, providing enhanced thermal flexibility. However, these parts exhibit lower slew rate (16V/µs vs. 75V/µs) and reduced gain bandwidth product (4 MHz vs. 13 MHz), requiring circuit-level evaluation for bandwidth-sensitive applications.

General-Purpose Alternatives: The LT2178 series (multiple variants) offers Active product status and RoHS3 compliance. These parts employ general-purpose amplifier topology with rail-to-rail output capability, differing fundamentally from the J-FET input stage of the AD746JR. The LT2178 variants operate across the full supply voltage range compatible with AD746JR (2.2V to 36V minimum/maximum overlap) and support extended temperature ranges (-40°C to 85°C for industrial variants). Selection of LT2178 variants requires application-specific evaluation due to significantly different performance characteristics (lower slew rate, reduced bandwidth, lower input bias current).

Compliance Considerations: All recommended substitutes maintain MSL 1 (Unlimited) moisture sensitivity classification and are classified under identical ECCN (EAR99) and HTSUS (8542.33.0001) codes, ensuring regulatory consistency.

Frequently Asked Questions (FAQ)

Q: Can the AD746JRZ be used as a direct replacement for the AD746JR?

A: Yes. The AD746JRZ is electrically and functionally identical to the AD746JR across all specified parameters. The primary difference is product status (Active vs. Obsolete) and packaging format. Both parts are 8-SOIC surface mount devices with identical pin configurations, electrical performance, and supply voltage requirements. Direct PCB substitution is supported without circuit modification.

Q: What are the key differences between the AD746JR and the LF353DT?

A: Both parts are J-FET dual-channel amplifiers in 8-SOIC packages with identical operating temperature ranges (0°C to 70°C). The AD746JR delivers superior performance with 75V/µs slew rate and 13 MHz bandwidth, compared to LF353DT's 16V/µs slew rate and 4 MHz bandwidth. The AD746JR exhibits higher input bias current (110 pA vs. 20 pA) but lower input offset voltage (300 µV vs. 3 mV). The LF353DT is RoHS3 compliant and REACH unaffected, with Active product status. Selection depends on bandwidth and slew rate requirements for the target application.

Q: Are the LT2178 series parts suitable replacements for the AD746JR?

A: The LT2178 series shares the 8-SOIC package format and dual-channel configuration but employs general-purpose amplifier topology rather than J-FET input architecture. The LT2178 variants feature significantly lower slew rate (0.04V/µs vs. 75V/µs), reduced bandwidth (85 kHz vs. 13 MHz), and substantially lower input bias current (3 nA vs. 110 pA). These parts are suitable only for applications where the AD746JR's high-speed and high-impedance characteristics are not required. Comprehensive circuit evaluation is necessary before substitution.

Q: What packaging options are available for substitute parts?

A: The AD746JRZ is available in Tube packaging. The LT2178 series offers multiple packaging variants: Tube (PBF designation) and Tape & Reel (TRPBF designation). The LF253DT and LF353DT are supplied in Cut Tape (CT) & Digi-Reel® format. All parts maintain identical 8-SOIC (0.154", 3.90mm Width) footprints, ensuring PCB compatibility regardless of packaging selection. Packaging choice affects supply chain logistics and reel quantities but not electrical performance or board-level integration.

Q: Do all substitute parts meet the same compliance standards as the AD746JR?

A: All recommended substitute parts maintain MSL 1 (Unlimited) moisture sensitivity classification. The AD746JRZ, LT2178 series, LF253DT, and LF353DT are all RoHS3 compliant and REACH unaffected. All parts share identical ECCN (EAR99) and HTSUS (8542.33.0001) classifications. Regulatory and environmental compliance is consistent across all substitutes.

Q: What is the supply voltage compatibility between the AD746JR and its substitutes?

A: The AD746JR operates across 9V to 36V supply range. The AD746JRZ maintains identical specifications. The LT2178 series supports 2.2V to 36V, providing lower minimum voltage capability. The LF253DT and LF353DT operate across 6V to 36V. All substitutes accommodate the AD746JR's 9V to 36V operating window, ensuring supply voltage compatibility in existing designs.

Q: Which substitute offers the best long-term availability?

A: The AD746JRZ is the recommended choice for long-term availability, as it is manufactured by the original designer (Analog Devices Inc.) and maintains Active product status. The LT2178 series and LF353DT also maintain Active status with established supply chains. The LF253DT provides extended temperature range (-40°C to 105°C) with Active status, offering additional thermal flexibility for demanding environments.

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