AD622AR Instrumentation Amplifier Equivalent & Substitute Parts

Part Overview

The AD622AR is a single-circuit instrumentation amplifier manufactured by Analog Devices Inc., housed in an 8-SOIC surface mount package. This device is classified as obsolete, though 1272 pieces remain in stock as new original inventory. The AD622AR operates across a supply voltage range of 5.2 V to 36 V with an operating temperature range of -40°C to 85°C, making it suitable for precision signal conditioning applications requiring low input bias current and low input offset voltage.

Due to the obsolete product status of the AD622AR, identifying equivalent and substitute parts is necessary for design continuity, long-term availability assurance, and procurement planning. Substitute parts must maintain functional compatibility while meeting the same electrical and mechanical specifications required for the application.

Key Parameters

Parameter	Value	Unit
Amplifier Type	Instrumentation	—
Number of Circuits	1	—
Slew Rate	1.2	V/µs
-3dB Bandwidth	1	MHz
Current - Input Bias	2	nA
Voltage - Input Offset	60	µV
Current - Supply	900	µA
Current - Output / Channel	18	mA
Voltage - Supply Span (Min)	5.2	V
Voltage - Supply Span (Max)	36	V
Operating Temperature	-40 to 85	°C
Mounting Type	Surface Mount	—
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the AD622AR is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Amplifier Type: Instrumentation
Number of Circuits: 1
Package / Case: 8-SOIC (0.154", 3.90mm Width)
Mounting Type: Surface Mount
Operating Temperature Range: -40°C to 85°C
Voltage Supply Span: Minimum 5.2 V to Maximum 36 V

Secondary Performance Parameters:

Slew Rate: 1.2 V/µs
-3dB Bandwidth: 1 MHz
Current - Input Bias: 2 nA
Voltage - Input Offset: 60 µV
Current - Supply: 900 µA
Current - Output / Channel: 18 mA

Substitute parts are grouped into two categories:

Direct Substitutes (Identical Electrical Specifications): Parts that match all primary and secondary performance parameters while maintaining the same package and operating conditions.

Functional Equivalents (Compatible Electrical Specifications): Parts that satisfy all primary substitution criteria and maintain functional compatibility within the same application class, though secondary performance parameters may differ within acceptable engineering tolerances.

Parameter Comparison

Parameter	AD622AR	AD622ARZ	INA118U	INA118U/2K5	INA118UB	INA118UB/2K5	INA121U	INA121U/2K5	INA121UA	INA121UA/2K5	INA128U
Manufacturer	Analog Devices	Analog Devices	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active
Amplifier Type	Instrumentation	Instrumentation	Instrumentation	Instrumentation	Instrumentation	Instrumentation	Instrumentation	Instrumentation	Instrumentation	Instrumentation	Instrumentation
Number of Circuits	1	1	1	1	1	1	1	1	1	1	1
Slew Rate (V/µs)	1.2	1.2	0.9	0.9	0.9	0.9	0.7	0.7	0.7	0.7	4
-3dB Bandwidth (MHz)	1	1	0.8	0.8	0.8	0.8	0.005	0.005	0.005	0.005	1.3
Current - Input Bias (nA)	2	2	1	1	1	1	0.004	0.004	0.004	0.004	2
Voltage - Input Offset (µV)	60	60	25	25	10	10	200	200	300	300	10
Current - Supply (µA)	900	900	350	350	350	350	450	450	450	450	700
Current - Output / Channel (mA)	18	18	12	12	12	12	14	14	14	14	15
Voltage - Supply Span Min (V)	5.2	5.2	2.7	2.7	2.7	2.7	4.5	4.5	4.5	4.5	4.5
Voltage - Supply Span Max (V)	36	36	36	36	36	36	36	36	36	36	36
Operating Temperature (°C)	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 85
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	3 (168 Hours)	3 (168 Hours)	3 (168 Hours)	2 (1 Year)	3 (168 Hours)	3 (168 Hours)	3 (168 Hours)	3 (168 Hours)	3 (168 Hours)

Engineering Selection Recommendations

Direct Substitute (Identical Specifications):

The AD622ARZ is the direct substitute for the AD622AR. Both parts share identical electrical specifications across all measured parameters: 1.2 V/µs slew rate, 1 MHz bandwidth, 2 nA input bias current, 60 µV input offset voltage, 900 µA supply current, and 18 mA output current. The AD622ARZ maintains the same 8-SOIC package and -40°C to 85°C operating temperature range. The primary distinction is product status: AD622ARZ is active with 9910 pieces in stock, compared to the obsolete AD622AR with 1272 pieces. The AD622ARZ is ROHS3 compliant and REACH unaffected, providing regulatory compliance advantages. Packaging differs (Tube for AD622ARZ versus unspecified for AD622AR), but both are surface mount compatible.

Functional Equivalents (Compatible Specifications):

The INA118U, INA118U/2K5, INA118UB, and INA118UB/2K5 (Texas Instruments) are functional equivalents suitable for applications where the AD622AR specifications can accommodate lower slew rate (0.9 V/µs versus 1.2 V/µs) and reduced bandwidth (800 kHz versus 1 MHz). These parts offer superior input offset voltage performance (10-25 µV versus 60 µV) and lower supply current (350 µA versus 900 µA). All maintain the 8-SOIC package, -40°C to 85°C operating temperature, and 36 V maximum supply voltage. The INA118 series is ROHS3 compliant and REACH unaffected. Packaging options include Tube and Cut Tape (CT) & Digi-Reel®. Moisture sensitivity levels range from MSL 2 to MSL 3.

The INA121U, INA121U/2K5, INA121UA, and INA121UA/2K5 (Texas Instruments) are functional equivalents for applications tolerating significantly reduced bandwidth (5 kHz versus 1 MHz) and lower slew rate (0.7 V/µs versus 1.2 V/µs). These parts feature ultra-low input bias current (4 pA versus 2 nA) and lower supply current (450 µA versus 900 µA). All maintain 8-SOIC packaging, -40°C to 85°C operating temperature, and 36 V maximum supply voltage. The INA121 series is ROHS3 compliant and REACH unaffected. Packaging options include Tube and Cut Tape (CT) & Digi-Reel®. Moisture sensitivity is MSL 3.

The INA128U (Texas Instruments) is a functional equivalent for applications requiring enhanced performance. It provides superior slew rate (4 V/µs versus 1.2 V/µs), higher bandwidth (1.3 MHz versus 1 MHz), and lower input offset voltage (10 µV versus 60 µV). Supply current is 700 µA (lower than AD622AR's 900 µA), and output current is 15 mA (lower than 18 mA). The INA128U maintains 8-SOIC packaging, -40°C to 85°C operating temperature, and 36 V maximum supply voltage. It is ROHS3 compliant and REACH unaffected with MSL 3 moisture sensitivity.

Regulatory and Compliance Considerations:

All substitute parts listed are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements. The AD622ARZ maintains identical specifications to the AD622AR while offering active product status and regulatory compliance. Texas Instruments parts provide additional compliance assurance through active product status and established supply chains.

Inventory and Availability:

The AD622ARZ offers the highest inventory availability among direct substitutes (9910 pieces). Among functional equivalents, INA121UA/2K5 provides the largest inventory (185,446 pieces), followed by INA118UB/2K5 (123,445 pieces). These inventory levels support long-term procurement planning and design continuity.

Frequently Asked Questions (FAQ)

Q: Can the INA118U series replace the AD622AR in all applications?

A: The INA118U series is functionally compatible with the AD622AR for applications where reduced slew rate (0.9 V/µs versus 1.2 V/µs) and lower bandwidth (800 kHz versus 1 MHz) are acceptable. The INA118 series offers superior input offset voltage (10-25 µV versus 60 µV) and lower power consumption (350 µA versus 900 µA). Applications requiring the full 1.2 V/µs slew rate or 1 MHz bandwidth must use the AD622ARZ or INA128U.

Q: What is the difference between AD622AR and AD622ARZ?

A: The AD622AR and AD622ARZ are electrically identical, sharing all performance specifications. The primary differences are product status (AD622AR is obsolete; AD622ARZ is active), packaging format (AD622ARZ is supplied in Tube), and inventory availability (AD622ARZ has 9910 pieces in stock). The AD622ARZ is ROHS3 compliant and REACH unaffected.

Q: Are all substitute parts available in the same 8-SOIC package?

A: Yes, all substitute parts listed are housed in the 8-SOIC (0.154", 3.90mm Width) surface mount package, ensuring mechanical and electrical compatibility with existing PCB designs.

Q: What are the moisture sensitivity implications of switching to Texas Instruments parts?

A: The AD622AR has MSL 1 (Unlimited), while most Texas Instruments substitutes have MSL 2 or MSL 3. MSL 3 (168 Hours) requires storage in controlled humidity environments and baking before reflow soldering. The INA118UB/2K5 offers MSL 2 (1 Year), providing a middle ground. Procurement and assembly processes must accommodate these moisture sensitivity requirements.

Q: Which substitute offers the best performance improvement over the AD622AR?

A: The INA128U provides the most significant performance enhancement, offering 4 V/µs slew rate (versus 1.2 V/µs), 1.3 MHz bandwidth (versus 1 MHz), and 10 µV input offset voltage (versus 60 µV). However, it requires evaluation for specific application requirements, as higher performance may introduce different noise characteristics or stability considerations.

Q: Can I use the INA121U series as a direct replacement?

A: The INA121U series is not a direct replacement due to significantly reduced bandwidth (5 kHz versus 1 MHz) and lower slew rate (0.7 V/µs versus 1.2 V/µs). It is suitable only for low-frequency signal conditioning applications where these reduced specifications are acceptable. The ultra-low input bias current (4 pA) makes it ideal for high-impedance sensor interfaces.

Q: What packaging options are available for substitute parts?

A: Substitute parts are available in Tube and Cut Tape (CT) & Digi-Reel® packaging formats. Tube packaging is standard for lower-volume applications, while Cut Tape & Digi-Reel® is preferred for automated assembly and higher-volume production. All packaging formats maintain the same 8-SOIC component footprint.

Q: Are all substitute parts suitable for the full -40°C to 85°C operating temperature range?

A: Yes, all substitute parts listed maintain the -40°C to 85°C operating temperature range, ensuring compatibility with industrial and extended-temperature applications.

Q: What is the supply voltage compatibility of substitute parts?

A: The AD622AR operates from 5.2 V to 36 V. The INA118 series operates from 2.7 V to 36 V (lower minimum), while the INA121 and INA128 series operate from 4.5 V to 36 V. All substitute parts support the full 36 V maximum supply voltage. Applications using supply voltages below 4.5 V must use the INA118 series.

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