INA188IDR Zero-Drift Amplifier Equivalent & Substitute Parts

Part Overview

The INA188IDR is an active zero-drift operational amplifier manufactured by Texas Instruments, designed for precision analog signal conditioning applications. This single-circuit, rail-to-rail amplifier operates across a 4V to 36V supply range with exceptionally low input offset voltage of 25 µV and minimal input bias current of 850 pA. The device is classified as Active product status and is RoHS3 compliant. Substitute parts are identified when the original INA188IDR becomes unavailable, when supply chain constraints exist, or when design requirements permit alternative amplifier topologies that meet or exceed the electrical and mechanical specifications of the primary component.

Substiute Parts

INA188IDR

Texas InstrumentsIn Stock: 6300INA188IDR Datasheet

Current PartRFQ

AD8422ARZ-R7

Analog Devices Inc.In Stock: 12245AD8422ARZ-R7 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the INA188IDR is determined by strict alignment of the following critical parameters:

Mechanical Compatibility:

• Package type: 8-SOIC (0.154", 3.90mm Width)
• Mounting type: Surface Mount
• Pin count and footprint equivalence

Electrical Compatibility:

• Supply voltage range: Minimum 4V, Maximum 36V (substitute must support full range or overlap)
• Output configuration: Rail-to-Rail capability
• Single circuit configuration (1 amplifier per package)
• Operating temperature range: -40°C to 125°C (or compatible subset)

Compliance & Certification:

• RoHS3 compliance status
• REACH compliance status
• Moisture Sensitivity Level (MSL) rating

The AD8422ARZ-R7 is identified as a manufacturer-recommended substitute. While it represents a different amplifier topology (Instrumentation Amplifier versus Zero-Drift Amplifier), it satisfies the mechanical package requirements and maintains electrical compatibility within the specified supply voltage and temperature operating windows.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection: INA188IDR

The INA188IDR remains the primary component choice when available. It is Active product status with full RoHS3 compliance and REACH unaffected designation. The device supports the complete operating temperature range of -40°C to 125°C and maintains the lowest input offset voltage specification at 25 µV, critical for precision measurement applications.

Substitute Selection: AD8422ARZ-R7

The AD8422ARZ-R7 is suitable as a substitute when INA188IDR availability is constrained. Both devices share identical 8-SOIC package geometry and surface mount configuration, ensuring direct PCB footprint compatibility. Both maintain Active product status and RoHS3 compliance.

Compatibility Constraints:

The AD8422ARZ-R7 operates with a minimum supply voltage of 4.6V (versus 4V for INA188IDR) and supports a reduced maximum operating temperature of 85°C (versus 125°C for INA188IDR). Applications requiring operation below 4.6V supply or above 85°C ambient temperature cannot use the AD8422ARZ-R7 as a substitute. The AD8422ARZ-R7 exhibits higher input offset voltage (60 µV versus 25 µV) and lower supply current (0.3 µA versus 1.4 mA), reflecting its instrumentation amplifier topology. The AD8422ARZ-R7 provides significantly higher bandwidth (2.2 MHz versus 600 kHz), which may introduce additional noise in bandwidth-limited applications.

Compliance Verification:

Both devices are ROHS3 compliant and REACH unaffected. The AD8422ARZ-R7 carries MSL rating of 1 (Unlimited), providing superior moisture protection compared to the INA188IDR MSL rating of 2 (1 Year).

Frequently Asked Questions (FAQ)

Q: Can the AD8422ARZ-R7 directly replace the INA188IDR in all applications?

A: No. The AD8422ARZ-R7 is suitable only for applications meeting all of the following conditions: (1) supply voltage ≥ 4.6V, (2) maximum operating temperature ≤ 85°C, (3) input offset voltage tolerance ≤ 60 µV, and (4) application bandwidth requirements compatible with 2.2 MHz bandwidth. Applications requiring operation at 4V supply, temperatures above 85°C, or precision offset voltage below 60 µV require the INA188IDR.

Q: Are the package footprints identical between INA188IDR and AD8422ARZ-R7?

A: Yes. Both devices use 8-SOIC (0.154", 3.90mm Width) surface mount packages with identical pin configurations and PCB footprints. No layout modifications are required for mechanical substitution.

Q: What is the difference between a Zero-Drift Amplifier and an Instrumentation Amplifier?

A: The INA188IDR is a zero-drift operational amplifier topology optimized for minimizing input offset voltage drift over temperature and time. The AD8422ARZ-R7 is an instrumentation amplifier topology designed for high common-mode rejection and differential signal conditioning. Both are single-circuit amplifiers with rail-to-rail output capability, but they serve different signal conditioning functions.

Q: Does the AD8422ARZ-R7 have better power efficiency than the INA188IDR?

A: Yes. The AD8422ARZ-R7 draws 0.3 µA supply current compared to 1.4 mA for the INA188IDR, representing approximately 4,600× lower quiescent current consumption. This advantage applies only when the AD8422ARZ-R7 operating constraints (minimum 4.6V supply, maximum 85°C temperature) are satisfied.

Q: Are both devices suitable for battery-powered applications?

A: The AD8422ARZ-R7 is preferred for battery-powered applications due to its significantly lower supply current (0.3 µA). The INA188IDR requires 1.4 mA supply current and is suitable for battery applications only when power budget permits. Both devices support the 4V minimum supply voltage typical of battery systems, though the AD8422ARZ-R7 requires minimum 4.6V.

Q: What is the MSL rating and why does it matter?

A: Moisture Sensitivity Level (MSL) indicates the maximum time a component can be stored in ambient conditions before requiring baking prior to reflow soldering. The INA188IDR has MSL 2 (1 Year), requiring baking if stored longer than one year. The AD8422ARZ-R7 has MSL 1 (Unlimited), requiring no time-based baking. For high-volume manufacturing with extended component storage, the AD8422ARZ-R7 provides logistical advantages.

Q: Can I use the AD8422ARZ-R7 in a precision measurement circuit designed for the INA188IDR?

A: Only if the circuit design tolerates the AD8422ARZ-R7 electrical differences: 60 µV input offset voltage (versus 25 µV), 2.2 MHz bandwidth (versus 600 kHz), and 0.8 V/µs slew rate (versus 0.9 V/µs). Precision measurement circuits typically require input offset voltage below 50 µV, making the AD8422ARZ-R7 unsuitable for this application class.