LT1122ACJ8 Equivalent & Substitute Parts

Part Overview

The LT1122ACJ8 is a J-FET input operational amplifier manufactured by Analog Devices Inc., housed in an 8-CDIP (0.300", 7.62mm) ceramic dual-in-line package. This device is classified as a linear amplifier with a single circuit configuration and is designated as obsolete. The LT1122ACJ8 features a slew rate of 80V/µs, gain bandwidth product of 14 MHz, and ultra-low input bias current of 10 pA, making it suitable for precision signal conditioning and high-impedance input applications.

Due to its obsolete product status, locating replacement units from original inventory sources presents supply chain challenges. Identifying equivalent substitute parts with compatible electrical and mechanical specifications is necessary to maintain design continuity and ensure system performance in applications where the LT1122ACJ8 was originally specified.

Substiute Parts

LT1122ACJ8

Analog Devices Inc.In Stock: 1023LT1122ACJ8 Datasheet

Current PartRFQ

OP42FZ

Analog Devices Inc.In Stock: 3341OP42FZ Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the LT1122ACJ8 is determined by strict alignment of electrical and mechanical parameters within the J-FET operational amplifier category. The following criteria establish substitution validity:

Primary Substitution Criteria:

• Amplifier Type: J-FET input architecture
• Number of Circuits: Single circuit configuration
• Package / Case: 8-CDIP (0.300", 7.62mm) ceramic dual-in-line package
• Mounting Type: Through Hole
• Moisture Sensitivity Level: 1 (Unlimited)

Secondary Electrical Parameters:

• Slew Rate: Minimum 50V/µs
• Gain Bandwidth Product: Minimum 10 MHz
• Current - Input Bias: Maximum 130 pA
• Voltage - Input Offset: Maximum 400 µV
• Current - Supply: Maximum 7.5 mA
• Voltage - Supply Span: Minimum 10V to 16V; Maximum 36V to 40V
• Operating Temperature Range: Minimum -40°C to -25°C; Maximum 85°C

The OP42FZ meets all primary substitution criteria and operates within acceptable ranges for secondary electrical parameters, establishing it as a valid equivalent substitute for the LT1122ACJ8.

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The LT1122ACJ8 is classified as obsolete, while the OP42FZ maintains active product status with current manufacturing and distribution support. Selection of the OP42FZ as a substitute provides access to ongoing supply chain availability and manufacturing continuity.

Compliance and Certification: The OP42FZ carries RoHS3 compliance certification and REACH unaffected status, meeting modern regulatory requirements for electronic component procurement. The LT1122ACJ8, as an obsolete device, does not carry current compliance certifications.

Electrical Performance Trade-offs: The OP42FZ exhibits lower slew rate (50V/µs versus 80V/µs) and reduced gain bandwidth product (10 MHz versus 14 MHz). Input bias current is higher (130 pA versus 10 pA), and input offset voltage is elevated (400 µV versus 120 µV). Supply current is lower (5.1 mA versus 7.5 mA). The minimum supply voltage requirement increases from 10V to 16V, and the operating temperature range narrows from -40°C to -25°C at the lower bound.

Mechanical and Packaging Compatibility: Both devices utilize identical 8-CDIP (0.300", 7.62mm) ceramic dual-in-line packages with through-hole mounting, ensuring direct physical compatibility on existing printed circuit boards without layout modification.

Frequently Asked Questions (FAQ)

Q: Can the OP42FZ be used as a direct replacement for the LT1122ACJ8 in all applications?

A: The OP42FZ is mechanically and functionally compatible as a substitute. However, applications requiring the LT1122ACJ8's superior slew rate (80V/µs), higher gain bandwidth product (14 MHz), or ultra-low input bias current (10 pA) must evaluate whether the OP42FZ's reduced performance specifications remain acceptable for the intended circuit function.

Q: What is the impact of the higher input bias current in the OP42FZ?

A: The OP42FZ input bias current of 130 pA is 13 times higher than the LT1122ACJ8's 10 pA specification. In high-impedance input circuits, this difference may introduce measurable input current errors. Applications with impedance sources below 1 MΩ typically experience negligible impact.

Q: Does the OP42FZ require different supply voltage levels?

A: The OP42FZ minimum supply voltage is 16V, compared to the LT1122ACJ8's 10V minimum. Existing designs operating at supply voltages between 10V and 15V require circuit modification or alternative substitutes. The maximum supply voltage of 40V for the OP42FZ accommodates the LT1122ACJ8's 36V maximum specification.

Q: Are there temperature range limitations with the OP42FZ?

A: The OP42FZ operating temperature range is -25°C to 85°C, compared to the LT1122ACJ8's -40°C to 85°C. Applications requiring operation below -25°C cannot use the OP42FZ as a substitute.

Q: What is the significance of the OP42FZ's active product status?

A: Active product status indicates current manufacturing, quality assurance, and distribution support. The obsolete LT1122ACJ8 has no ongoing production or manufacturer support. Selection of the OP42FZ ensures long-term component availability and supply chain reliability.

Q: Are the 8-CDIP packages physically identical?

A: Both the LT1122ACJ8 and OP42FZ use 8-CDIP (0.300", 7.62mm) ceramic dual-in-line packages with identical pin spacing and through-hole mounting requirements. No printed circuit board layout modifications are necessary for physical substitution.

Q: What compliance certifications apply to the OP42FZ?

A: The OP42FZ carries RoHS3 compliance certification and is REACH unaffected. These certifications meet current regulatory requirements for electronic component procurement in regulated industries and markets.