LM6181IMX Equivalent & Substitute Parts

Part Overview

The LM6181IMX is a Current Feedback Amplifier manufactured by Texas Instruments, housed in a 16-SOIC package. This device is classified as obsolete, indicating discontinued production and limited availability for new designs. The LM6181IMX operates across a wide supply voltage range (7V to 32V) with a slew rate of 2000V/µs and -3dB bandwidth of 100 MHz, making it suitable for high-speed signal conditioning applications.

Due to its obsolete status, identifying functionally equivalent substitute parts is necessary for design continuity, procurement reliability, and long-term product support. The substitute parts listed below maintain compatibility with the core electrical and mechanical requirements of the LM6181IMX while offering active product status and improved availability.

Substiute Parts

LM6181IMX

Texas InstrumentsIn Stock: 2883LM6181IMX Datasheet

Current PartRFQ

OPA694ID

Texas InstrumentsIn Stock: 1697OPA694ID Datasheet

MFR RecommendedRFQ

ISL28177FBZ

Renesas Electronics CorporationIn Stock: 1367ISL28177FBZ Datasheet

MFR RecommendedRFQ

ISL28177FBZ-T13

Renesas Electronics CorporationIn Stock: 2530ISL28177FBZ-T13 Datasheet

MFR RecommendedRFQ

ISL28177FBZ-T7

Renesas Electronics CorporationIn Stock: 1925ISL28177FBZ-T7 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LM6181IMX is determined by the following critical parameters:

Primary Substitution Criteria:

• Amplifier Type: Current Feedback architecture
• Number of Circuits: Single circuit configuration
• Operating Temperature Range: Minimum -40°C to 85°C
• Supply Voltage Compatibility: Minimum 7V support
• Mounting Type: Surface Mount
• RoHS3 Compliance: Required for regulatory alignment

Secondary Compatibility Factors:

• Slew Rate: Minimum 1700 V/µs (LM6181IMX operates at 2000 V/µs)
• Bandwidth Performance: Minimum 100 MHz (-3dB)
• Input Bias Current: Maximum 5 µA
• Output Current Capability: Minimum 80 mA per channel

The substitute parts identified below satisfy the primary criteria. However, package form factor differences (16-SOIC vs. 8-SOIC) and amplifier type variations (Current Feedback vs. General Purpose) introduce design considerations that must be evaluated within specific application contexts.

Parameter Comparison

Engineering Selection Recommendations

OPA694ID (Texas Instruments)

The OPA694ID is a Current Feedback Amplifier from Texas Instruments, maintaining architectural alignment with the LM6181IMX. This device is actively manufactured and carries ROHS3 compliance. The OPA694ID operates within the same temperature range (-40°C to 85°C) and shares identical input bias current specifications (5 µA). However, the maximum supply voltage is limited to 12.6V compared to the LM6181IMX maximum of 32V. The OPA694ID delivers superior bandwidth performance (1.5 GHz vs. 100 MHz) and lower input offset voltage (500 µV vs. 3.5 mV). The package form factor differs (8-SOIC vs. 16-SOIC), requiring PCB layout modification. Output current capability is reduced to 80 mA per channel versus 130 mA. Selection of the OPA694ID is appropriate for applications where the reduced supply voltage range is acceptable and higher bandwidth performance is beneficial.

ISL28177FBZ, ISL28177FBZ-T13, ISL28177FBZ-T7 (Renesas Electronics)

The ISL28177 series devices are General Purpose Amplifiers manufactured by Renesas Electronics. These parts are actively produced and ROHS3 compliant. All three variants (ISL28177FBZ, ISL28177FBZ-T13, ISL28177FBZ-T7) share identical electrical specifications and differ only in packaging format (Tube vs. Tape & Reel). The ISL28177 series operates across an extended temperature range (-40°C to 125°C), exceeding the LM6181IMX specification. Supply voltage range extends to 40V maximum, accommodating higher voltage applications. Input bias current is significantly lower (200 pA vs. 5 µA), and input offset voltage is reduced (150 µV vs. 3.5 mV). However, slew rate is substantially lower (0.2 V/µs vs. 2000 V/µs), and bandwidth is limited to 600 kHz gain-bandwidth product versus 100 MHz. Output current per channel is reduced to 30 mA. The ISL28177 series represents a General Purpose architecture rather than Current Feedback, introducing functional differences. Selection is appropriate for low-speed, low-power applications where the reduced slew rate and bandwidth are acceptable.

Packaging and Procurement Considerations

The OPA694ID is supplied in Tube packaging. The ISL28177FBZ is supplied in Tube packaging. The ISL28177FBZ-T13 and ISL28177FBZ-T7 are supplied in Tape & Reel format, suitable for automated assembly processes. Tape & Reel packaging typically offers cost advantages for high-volume production.

Frequently Asked Questions (FAQ)

Q: Can the OPA694ID directly replace the LM6181IMX without circuit modification?

A: The OPA694ID shares Current Feedback architecture and identical input bias current with the LM6181IMX. However, the maximum supply voltage is reduced from 32V to 12.6V. If your application operates within the 12.6V limit, substitution is feasible. The package form factor differs (8-SOIC vs. 16-SOIC), requiring PCB layout changes. Pin configuration must be verified before implementation.

Q: Why do the ISL28177 variants show lower slew rate and bandwidth than the LM6181IMX?

A: The ISL28177 series are General Purpose Amplifiers, whereas the LM6181IMX is a Current Feedback Amplifier. These are distinct architectural classes optimized for different performance profiles. General Purpose amplifiers prioritize low power consumption and wide supply voltage range, while Current Feedback amplifiers prioritize high slew rate and bandwidth. The ISL28177 series is not suitable for applications requiring the 2000 V/µs slew rate or 100 MHz bandwidth of the LM6181IMX.

Q: What is the difference between ISL28177FBZ, ISL28177FBZ-T13, and ISL28177FBZ-T7?

A: These three part numbers represent identical electrical devices with different packaging formats. ISL28177FBZ is supplied in Tube packaging. ISL28177FBZ-T13 and ISL28177FBZ-T7 are supplied in Tape & Reel format. The "-T13" and "-T7" designations indicate different tape specifications. Electrical performance is identical across all three variants. Selection depends on procurement and assembly requirements.

Q: Is the OPA694ID suitable for high-voltage applications requiring 32V operation?

A: No. The OPA694ID maximum supply voltage is 12.6V. Applications requiring 32V operation cannot use the OPA694ID. The ISL28177 series supports up to 40V supply voltage and may be considered, provided the reduced slew rate (0.2 V/µs) and bandwidth (600 kHz) are acceptable for your application requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. The OPA694ID, ISL28177FBZ, ISL28177FBZ-T13, and ISL28177FBZ-T7 are all ROHS3 compliant, matching the compliance status of the LM6181IMX.

Q: What is the moisture sensitivity level difference between the substitute parts?

A: The LM6181IMX and ISL28177 series carry MSL 1 (Unlimited), indicating no moisture sensitivity restrictions. The OPA694ID carries MSL 2 (1 Year), requiring storage in controlled humidity conditions and baking before reflow soldering if shelf life exceeds one year. This represents a more stringent handling requirement.

Q: Can I use the ISL28177 series in a high-speed signal conditioning circuit originally designed for the LM6181IMX?

A: The ISL28177 series is not recommended for high-speed applications. The 0.2 V/µs slew rate and 600 kHz bandwidth are insufficient for circuits requiring the 2000 V/µs slew rate and 100 MHz bandwidth of the LM6181IMX. Circuit performance will be degraded. The OPA694ID is a more appropriate substitute for high-speed applications, provided supply voltage requirements are compatible.

Q: What are the key electrical differences I must evaluate before selecting a substitute?

A: Evaluate the following parameters in order of priority: (1) Supply voltage range compatibility with your application; (2) Required slew rate and bandwidth performance; (3) Output current capability; (4) Input offset voltage and bias current specifications; (5) Operating temperature range; (6) Package form factor and PCB layout constraints.