OP491GS Equivalent & Substitute Parts

Part Overview

The OP491GS is a general-purpose operational amplifier manufactured by Analog Devices Inc., configured as a 4-circuit rail-to-rail amplifier in a 14-SOIC surface mount package. This device is classified as obsolete, indicating that direct procurement from primary sources may be limited. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support ongoing production requirements for applications utilizing this amplifier configuration.

Key Parameters

Parameter	Value	Unit
Number of Circuits	4	—
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 (x4 Channels)	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	14-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the OP491GS is determined by the following critical parameters: four-circuit configuration, rail-to-rail output capability, surface mount packaging, and electrical performance specifications within defined tolerances. Substitute parts must maintain compatibility across these dimensions to ensure functional equivalence in existing circuit designs.

The substitute parts are grouped into two categories:

Direct Equivalent (Packaging Variant): OP491GSZ represents a direct functional equivalent with identical electrical specifications and the same 14-SOIC package footprint. The primary distinction is packaging format (Tube versus unspecified for the original OP491GS) and product status (Active versus Obsolete).

Similar Equivalent (Package Variant): ADA4091-4ARUZ and TS924IDT provide functional substitution with variations in electrical performance and package type. These parts maintain the four-circuit, rail-to-rail architecture and surface mount configuration but differ in specific performance metrics and package dimensions. Selection between these alternatives depends on application-specific requirements and package compatibility with existing printed circuit board designs.

Parameter Comparison

Parameter	OP491GS	OP491GSZ	ADA4091-4ARUZ	TS924IDT
Manufacturer	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.	STMicroelectronics
Product Status	Obsolete	Active	Active	Active
Number of Circuits	4	4	4	4
Output Type	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail
Slew Rate (V/µs)	0.5	0.5	0.46	1.3
Gain Bandwidth Product (MHz)	3	3	1.27	4
Current - Input Bias (nA)	30	30	50	15
Voltage - Input Offset (µV)	80	80	35	3000
Current - Supply (µA, x4 Channels)	260	260	200	1000
Current - Output / Channel (mA)	16	16	20	80
Voltage - Supply Span Min (V)	2.7	2.7	3	2.7
Voltage - Supply Span Max (V)	12	12	30	12
Operating Temperature (°C)	-40 to 125	-40 to 125	-40 to 125	-40 to 125
Package / Case	14-SOIC (0.154", 3.90mm)	14-SOIC (0.154", 3.90mm)	14-TSSOP (0.173", 4.40mm)	14-SOIC (0.154", 3.90mm)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

OP491GSZ is the primary substitute for OP491GS applications. This part maintains identical electrical specifications and package footprint compatibility, ensuring direct replacement capability without circuit redesign. OP491GSZ carries Active product status and ROHS3 compliance, providing superior supply chain availability and regulatory alignment compared to the obsolete OP491GS.

ADA4091-4ARUZ serves as an alternative substitute when supply constraints on OP491GSZ occur or when the extended supply voltage range (3 V to 30 V maximum) is required. This part features improved input offset voltage (35 µV versus 80 µV) and higher output current capability (20 mA versus 16 mA per channel). However, the 14-TSSOP package requires printed circuit board layout modification, as the package width differs from the 14-SOIC footprint. The reduced gain bandwidth product (1.27 MHz versus 3 MHz) may impact applications with higher frequency requirements.

TS924IDT provides substitution for applications prioritizing higher slew rate (1.3 V/µs versus 0.5 V/µs) and gain bandwidth product (4 MHz versus 3 MHz) performance. This STMicroelectronics device maintains 14-SOIC package compatibility and includes automotive-grade qualification (AEC-Q100). The significantly higher supply current (1 mA total versus 260 µA) and output current capability (80 mA per channel versus 16 mA) indicate enhanced drive capability suitable for demanding applications. The substantially higher input offset voltage (3 mV versus 80 µV) requires evaluation against precision requirements.

All three substitute parts maintain the four-circuit rail-to-rail configuration, surface mount technology, and -40°C to 125°C operating temperature range of the original OP491GS.

Frequently Asked Questions (FAQ)

Q: Can OP491GSZ be used as a direct replacement for OP491GS without circuit modification?

A: Yes. OP491GSZ provides identical electrical specifications and 14-SOIC package footprint compatibility. Direct substitution on existing printed circuit boards is supported without design changes.

Q: What are the primary differences between OP491GSZ and ADA4091-4ARUZ?

A: The primary differences are package type and electrical performance. OP491GSZ uses 14-SOIC packaging (0.154" width), while ADA4091-4ARUZ uses 14-TSSOP packaging (0.173" width), requiring printed circuit board layout modification. ADA4091-4ARUZ offers improved input offset voltage (35 µV versus 80 µV), higher output current (20 mA versus 16 mA per channel), and extended supply voltage range (3 V to 30 V versus 2.7 V to 12 V). However, ADA4091-4ARUZ has lower gain bandwidth product (1.27 MHz versus 3 MHz).

Q: Is TS924IDT suitable for applications requiring the same performance as OP491GS?

A: TS924IDT provides functional substitution with enhanced performance in slew rate and gain bandwidth product. However, the significantly higher input offset voltage (3 mV versus 80 µV) and supply current (1 mA versus 260 µA) require application-specific evaluation. TS924IDT is compatible with 14-SOIC package footprints and includes automotive-grade qualification.

Q: What is the impact of package differences on printed circuit board design?

A: OP491GSZ and TS924IDT both use 14-SOIC packaging and are footprint-compatible with OP491GS. ADA4091-4ARUZ uses 14-TSSOP packaging with different pin spacing and body dimensions, requiring printed circuit board redesign and re-layout for implementation.

Q: Are all substitute parts RoHS compliant?

A: OP491GSZ, ADA4091-4ARUZ, and TS924IDT are all ROHS3 compliant. The original OP491GS does not specify RoHS status.

Q: Which substitute part is recommended for new designs?

A: Selection depends on application requirements. For direct replacement of existing OP491GS designs, OP491GSZ is recommended due to identical specifications and package compatibility. For new designs requiring extended supply voltage range, ADA4091-4ARUZ is suitable. For automotive applications or designs requiring higher performance metrics, TS924IDT provides enhanced capabilities with AEC-Q100 qualification.

Q: What is the significance of the Moisture Sensitivity Level (MSL) rating?

A: All parts, including OP491GS and its substitutes, carry MSL 1 (Unlimited) rating, indicating no moisture sensitivity restrictions during storage, handling, or assembly processes.

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