OP291GS Equivalent & Substitute Parts

Part Overview

The OP291GS is a general-purpose operational amplifier manufactured by Analog Devices Inc., configured as a dual-channel (2 circuit) rail-to-rail amplifier in an 8-SOIC surface mount package. This device is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and production continuity. The OP291GS operates across a supply voltage range of 2.7 V to 12 V with an operating temperature range of -40°C to 125°C, making it suitable for low-power analog signal processing applications.

Key Parameters

Parameter	Value	Unit
Amplifier Type	General Purpose	—
Number of Circuits	2	—
Output Type	Rail-to-Rail	—
Slew Rate	0.5	V/µs
Gain Bandwidth Product	3	MHz
Current - Input Bias	30	nA
Voltage - Input Offset	80	µV
Current - Supply (per Channel)	260	µA
Current - Output / Channel	16	mA
Voltage - Supply Span (Min)	2.7	V
Voltage - Supply Span (Max)	12	V
Operating Temperature	-40 to 125	°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 OP291GS is determined by strict alignment of electrical and mechanical parameters within the linear amplifier category. The primary substitution criteria are:

Direct Substitutes (Identical Electrical Specifications): Direct substitutes maintain all electrical parameters within the same tolerance bands, including slew rate, gain bandwidth product, input bias current, input offset voltage, supply current, output current capability, and supply voltage range. These parts are functionally interchangeable with no circuit redesign required.

Similar Substitutes (Compatible Electrical Specifications with Parameter Variations): Similar substitutes operate within the same functional category and package form factor but exhibit variations in one or more electrical parameters. Substitution is valid when the application requirements permit the parameter deviations. Key differentiators include amplifier type (General Purpose vs. CMOS), slew rate performance, gain bandwidth product, input offset voltage, and supply voltage operating range.

Critical Compatibility Parameters:

Package / Case: 8-SOIC form factor (mandatory for mechanical compatibility)
Mounting Type: Surface Mount (mandatory for PCB assembly compatibility)
Number of Circuits: 2 (dual-channel configuration)
Output Type: Rail-to-Rail (required for full supply voltage swing capability)
Operating Temperature Range: Must encompass or match the application requirement

Parameter Comparison

Part Number	Manufacturer	Product Status	Slew Rate (V/µs)	GBW (MHz)	Input Bias (nA)	Input Offset (µV)	Supply Current (µA)	Output Current (mA)	Supply Min (V)	Supply Max (V)	Temp Range (°C)
OP291GS	Analog Devices Inc.	Obsolete	0.5	3	30	80	260	16	2.7	12	-40 to 125
OP291GSZ	Analog Devices Inc.	Active	0.5	3	30	80	260	16	2.7	12	-40 to 125
ADA4091-2ARZ	Analog Devices Inc.	Active	0.46	1.27	50	45	200	20	3	30	-40 to 125
ALD2704ASAL	Advanced Linear Devices Inc.	Active	5	2.1	1	1000	5	15	6.5	10	0 to 70
ALD2704BSAL	Advanced Linear Devices Inc.	Active	5	2.1	1	2000	5	15	6.5	10	0 to 70
ALD2704SAL	Advanced Linear Devices Inc.	Active	5	2.1	1	5000	5	15	6.5	10	0 to 70
ALD2732ASAL	Advanced Linear Devices Inc.	Active	1.9	1.5	10	600	—	—	4	10	0 to 70
ALD2732SAL	Advanced Linear Devices Inc.	Active	1.9	1.5	10	2000	—	—	4	10	0 to 70

Engineering Selection Recommendations

Direct Replacement (No Circuit Modification Required):

The OP291GSZ is the direct equivalent of the OP291GS. This part is manufactured by Analog Devices Inc. and maintains identical electrical specifications across all parameters. The OP291GSZ is classified as Active product status, ensuring ongoing availability and manufacturing support. This component is ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements. The OP291GSZ is supplied in Tube packaging and is the recommended primary substitute for obsolete OP291GS applications.

Compatible Substitutes (Application-Dependent Selection):

The ADA4091-2ARZ is an active Analog Devices Inc. product offering extended supply voltage range (3 V to 30 V) compared to the OP291GS (2.7 V to 12 V). This part maintains the same operating temperature range (-40°C to 125°C) and dual-channel rail-to-rail configuration. The ADA4091-2ARZ exhibits lower input offset voltage (45 µV vs. 80 µV) and higher output current capability (20 mA vs. 16 mA). However, it operates at reduced slew rate (0.46 V/µs vs. 0.5 V/µs) and lower gain bandwidth product (1.27 MHz vs. 3 MHz). Selection of the ADA4091-2ARZ is appropriate for applications requiring extended supply voltage operation and lower input offset specifications, provided the reduced bandwidth performance is acceptable.

The ALD2704ASAL, ALD2704BSAL, and ALD2704SAL are CMOS amplifiers from Advanced Linear Devices Inc. with significantly higher slew rate (5 V/µs) and lower input bias current (1 pA). These parts operate within a narrower supply voltage range (6.5 V to 10 V) and restricted temperature range (0°C to 70°C). Selection of these variants is appropriate for applications requiring high-speed performance and low input bias current, provided the supply voltage and temperature constraints are compatible with the application.

The ALD2732ASAL and ALD2732SAL are general-purpose amplifiers from Advanced Linear Devices Inc. with intermediate slew rate (1.9 V/µs) and supply voltage range (4 V to 10 V). These parts operate within the restricted temperature range (0°C to 70°C). Selection of these variants is appropriate for applications with moderate bandwidth requirements and lower supply voltage operation, provided the temperature constraints are acceptable.

All substitute parts maintain the 8-SOIC surface mount package form factor and dual-channel configuration, ensuring mechanical compatibility with existing PCB designs.

Frequently Asked Questions (FAQ)

Q: Can the OP291GSZ be used as a direct replacement for the OP291GS without circuit modification?

A: Yes. The OP291GSZ maintains identical electrical specifications across all parameters including slew rate, gain bandwidth product, input bias current, input offset voltage, supply current, output current, and supply voltage range. The OP291GSZ is the direct equivalent and requires no circuit modification. The primary difference is product status (Active vs. Obsolete) and packaging format (Tube vs. unspecified for the original part).

Q: What are the key differences between the OP291GS and ADA4091-2ARZ?

A: The ADA4091-2ARZ offers extended supply voltage range (3 V to 30 V vs. 2.7 V to 12 V), lower input offset voltage (45 µV vs. 80 µV), and higher output current capability (20 mA vs. 16 mA). However, the ADA4091-2ARZ operates at reduced slew rate (0.46 V/µs vs. 0.5 V/µs) and lower gain bandwidth product (1.27 MHz vs. 3 MHz). Both parts maintain the same operating temperature range (-40°C to 125°C) and dual-channel rail-to-rail configuration. Selection depends on whether the application requires extended supply voltage operation and can tolerate reduced bandwidth performance.

Q: Why do the ALD2704 series parts have different input offset voltage specifications?

A: The ALD2704ASAL, ALD2704BSAL, and ALD2704SAL are variants of the same base product (ALD2704) with different input offset voltage grades. The ASAL variant specifies 1 mV (1000 µV), the BSAL variant specifies 2 mV (2000 µV), and the SAL variant specifies 5 mV (5000 µV). These variants allow selection based on input offset voltage requirements. All three variants maintain identical slew rate (5 V/µs), gain bandwidth product (2.1 MHz), and other electrical parameters.

Q: Are the ALD2704 series parts suitable replacements for the OP291GS?

A: The ALD2704 series parts are compatible substitutes only for applications where the narrower supply voltage range (6.5 V to 10 V) and restricted operating temperature range (0°C to 70°C) are acceptable. The ALD2704 series offers significantly higher slew rate (5 V/µs vs. 0.5 V/µs) and lower input bias current (1 pA vs. 30 nA), making them suitable for high-speed applications. However, the reduced supply voltage range and temperature range limit their applicability to designs originally specified for the OP291GS operating at -40°C to 125°C or with supply voltages below 6.5 V or above 10 V.

Q: What is the significance of the 8-SOIC package specification?

A: The 8-SOIC (Small Outline Integrated Circuit) package is a surface mount form factor with 0.154 inches (3.90 mm) width. All substitute parts listed maintain this identical package specification, ensuring mechanical and electrical compatibility with existing PCB designs. No PCB layout modification is required when substituting between parts with the same 8-SOIC package designation.

Q: Why is the OP291GSZ recommended over other substitutes?

A: The OP291GSZ is recommended as the primary substitute because it is manufactured by the same company (Analog Devices Inc.) as the original OP291GS, maintains identical electrical specifications across all parameters, and is classified as Active product status with ongoing manufacturing support. The OP291GSZ is ROHS3 compliant and REACH unaffected, meeting current regulatory requirements. No circuit modification or design validation is required when substituting the OP291GSZ for the obsolete OP291GS.

Q: Can the ALD2732 series parts replace the OP291GS in all applications?

A: The ALD2732 series parts are suitable substitutes only for applications where the narrower supply voltage range (4 V to 10 V) and restricted operating temperature range (0°C to 70°C) are acceptable. The ALD2732 series offers lower input bias current (10 pA vs. 30 nA) and intermediate slew rate (1.9 V/µs vs. 0.5 V/µs). Applications requiring operation at -40°C to 125°C or with supply voltages below 4 V or above 10 V cannot use the ALD2732 series without design modification.

Q: What compliance certifications should be verified when selecting a substitute part?

A: All active substitute parts listed (OP291GSZ, ADA4091-2ARZ, ALD2704ASAL, ALD2704BSAL, ALD2704SAL, ALD2732ASAL, ALD2732SAL) are ROHS3 compliant and REACH unaffected. These certifications indicate compliance with current environmental and regulatory requirements for electronic components. The Moisture Sensitivity Level (MSL) for all parts is 1 (Unlimited), indicating no moisture sensitivity constraints during storage and handling.

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