INA122U Instrumentation Amplifier: Equivalent & Substitute Parts

Part Overview

The INA122U is a single-circuit instrumentation amplifier manufactured by Texas Instruments in 8-SOIC surface mount packaging. This device operates across a wide supply voltage range (2.2V to 36V) and is designed for precision signal conditioning applications requiring low input bias current and low input offset voltage. The INA122U is classified as Last Time Buy, indicating end-of-life status. Identification of compatible substitute parts is necessary to ensure design continuity and maintain supply chain reliability for new production and long-term support.

Substiute Parts

INA122U

Texas InstrumentsIn Stock: 3354INA122U Datasheet

Current PartRFQ

INA122U/2K5

Texas InstrumentsIn Stock: 3796INA122U/2K5 Datasheet

MFR RecommendedRFQ

AD627ARZ

Analog Devices Inc.In Stock: 10296AD627ARZ Datasheet

MFR RecommendedRFQ

AD627ARZ-R7

Analog Devices Inc.In Stock: 40187AD627ARZ-R7 Datasheet

MFR RecommendedRFQ

AD627ARZ-RL

Analog Devices Inc.In Stock: 10489AD627ARZ-RL Datasheet

MFR RecommendedRFQ

AD627BRZ

Analog Devices Inc.In Stock: 16991AD627BRZ Datasheet

MFR RecommendedRFQ

AD627BRZ-R7

Analog Devices Inc.In Stock: 3912AD627BRZ-R7 Datasheet

MFR RecommendedRFQ

AD627BRZ-RL

Analog Devices Inc.In Stock: 2949AD627BRZ-RL Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the INA122U is determined by strict equivalence across the following critical parameters:

Mandatory Matching Criteria:

• Amplifier Type: Instrumentation
• Number of Circuits: 1
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Mounting Type: Surface Mount
• Voltage - Supply Span: 2.2V to 36V
• Operating Temperature: -40°C to 85°C
• RoHS Status: ROHS3 Compliant

Performance Parameters (Allowable Variation): Substitute parts may exhibit different values for Slew Rate, -3dB Bandwidth, Input Bias Current, Input Offset Voltage, and Output Current, provided the substitute part meets or exceeds the functional requirements of the application circuit.

The substitute parts identified are grouped into two categories:

1. Texas Instruments INA122U Variants (INA122U/2K5): Identical electrical specifications with alternative packaging format (Tape & Reel vs. Tube).

2. Analog Devices AD627 Series (AD627ARZ, AD627ARZ-R7, AD627ARZ-RL, AD627BRZ, AD627BRZ-R7, AD627BRZ-RL): Rail-to-rail output instrumentation amplifiers with equivalent supply voltage range and package footprint. These devices feature improved input bias current (2 nA vs. 10 nA) and lower input offset voltage specifications.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical Performance):

The INA122U/2K5 is the primary substitute for the INA122U. Both devices are manufactured by Texas Instruments and maintain identical electrical specifications across all performance parameters. The only difference is packaging format: INA122U/2K5 is supplied in Tape & Reel format, while the original INA122U is supplied in Tube format. The INA122U/2K5 carries Active product status, ensuring long-term availability and manufacturing support. This part is suitable for direct substitution in new designs and production runs.

For Enhanced Performance Substitution:

The Analog Devices AD627 series (AD627ARZ, AD627ARZ-R7, AD627ARZ-RL, AD627BRZ, AD627BRZ-R7, AD627BRZ-RL) provides functional equivalence with improved electrical characteristics. All AD627 variants feature:

• Lower input bias current (2 nA vs. 10 nA)
• Lower input offset voltage (50 µV for A-grade; 25 µV for B-grade vs. 100 µV)
• Rail-to-rail output capability
• Active product status with full manufacturing support
• Identical 8-SOIC package footprint and supply voltage range

The AD627 series is suitable for applications where improved input stage performance and rail-to-rail output swing are beneficial. Circuit validation is required to confirm compatibility with existing gain-setting resistor networks and output load characteristics.

Packaging Selection:

• Tube Packaging: INA122U/2K5, AD627ARZ, AD627BRZ — suitable for lower-volume production and manual assembly
• Cut Tape & Digi-Reel Packaging: AD627ARZ-R7, AD627ARZ-RL, AD627BRZ-R7, AD627BRZ-RL — optimized for automated pick-and-place assembly and high-volume manufacturing

All substitute parts maintain ROHS3 compliance and are REACH unaffected, meeting regulatory requirements equivalent to the original INA122U.

Frequently Asked Questions (FAQ)

Q: Can I use INA122U/2K5 as a direct replacement for INA122U?

A: Yes. The INA122U/2K5 is electrically identical to the INA122U and shares the same 8-SOIC package footprint. The only difference is the packaging format (Tape & Reel vs. Tube). No circuit modifications are required. The INA122U/2K5 is the recommended substitute for continued production support.

Q: What are the differences between the AD627 series and the INA122U?

A: The AD627 series offers improved input stage performance with lower input bias current (2 nA vs. 10 nA) and lower input offset voltage (50 µV or 25 µV vs. 100 µV). The AD627 also provides rail-to-rail output capability. However, the AD627 has a lower slew rate (0.06 V/µs vs. 0.16 V/µs) and narrower bandwidth (80 kHz vs. 120 kHz). Both families maintain identical supply voltage range and operating temperature specifications.

Q: Are all substitute parts in the same package?

A: Yes. All substitute parts use the 8-SOIC package with 0.154" width (3.90mm). The package footprint is identical across all listed parts, enabling direct PCB compatibility. Packaging format (Tube, Cut Tape, or Tape & Reel) affects handling and assembly processes but not electrical or mechanical fit.

Q: Which AD627 variant should I select: A-grade or B-grade?

A: The A-grade (AD627ARZ series) specifies 50 µV input offset voltage, while the B-grade (AD627BRZ series) specifies 25 µV. Select based on application precision requirements. For applications requiring tighter offset voltage tolerance, the B-grade is preferred. Both grades are functionally equivalent in all other parameters.

Q: What is the difference between AD627ARZ-R7 and AD627ARZ-RL?

A: Both parts are identical in electrical specifications and package type (Cut Tape & Digi-Reel). The suffix designations indicate different reel configurations or supplier-specific packaging options. Consult the supplier datasheet for specific reel specifications. Functionally, both are equivalent for circuit design purposes.

Q: Is the INA122U still available for new designs?

A: The INA122U is classified as Last Time Buy, indicating end-of-life status. For new designs, use INA122U/2K5 (Texas Instruments) or AD627 series (Analog Devices) to ensure long-term supply chain continuity and manufacturing support.

Q: Can I mix different substitute parts in the same production batch?

A: All listed substitute parts are functionally equivalent within the specified parameter ranges and share identical package footprints. However, mixing different manufacturers or device grades in the same production batch may introduce variations in input offset voltage and bias current. For consistency, maintain a single part number per production run unless circuit design explicitly accommodates the parameter variations.

Q: Do I need to modify my PCB layout for any of these substitutes?

A: No. All substitute parts use the 8-SOIC package with identical pin assignments and footprint dimensions. No PCB layout modifications are required. Existing PCB designs for the INA122U are directly compatible with all listed substitute parts.