LM7121IM5 Equivalent & Substitute Parts

Part Overview

The LM7121IM5 is a voltage feedback operational amplifier manufactured by Texas Instruments, housed in a SOT-23-5 surface mount package. This device functions as a single-circuit operational amplifier with high slew rate and bandwidth characteristics suitable for precision analog signal processing applications. The LM7121IM5 carries a Last Time Buy product status, indicating discontinued production. Identification of equivalent and substitute parts is necessary to ensure design continuity and procurement availability for new production runs and long-term system support.

Substiute Parts

LM7121IM5

Texas InstrumentsIn Stock: 1624LM7121IM5 Datasheet

Current PartRFQ

LM7121IM5/NOPB

Texas InstrumentsIn Stock: 189136LM7121IM5/NOPB Datasheet

DirectRFQ

LM7121IM5X/NOPB

Texas InstrumentsIn Stock: 4129LM7121IM5X/NOPB Datasheet

MFR RecommendedRFQ

LT1815CS5#TR

Analog Devices Inc.In Stock: 1119LT1815CS5#TR Datasheet

MFR RecommendedRFQ

LT1815CS5#TRMPBF

Analog Devices Inc.In Stock: 2232LT1815CS5#TRMPBF Datasheet

MFR RecommendedRFQ

LT1815CS5#TRPBF

Analog Devices Inc.In Stock: 2069LT1815CS5#TRPBF Datasheet

MFR RecommendedRFQ

LT1815IS5#TRMPBF

Analog Devices Inc.In Stock: 2467LT1815IS5#TRMPBF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LM7121IM5 is determined by the following critical parameters: amplifier type (voltage feedback), number of circuits (single), package type (SOT-23-5 surface mount), and electrical performance specifications including slew rate, gain bandwidth product, supply voltage range, and operating temperature range.

The substitute parts are grouped into two categories:

Category 1: Texas Instruments LM7121 Series (Direct Manufacturer Variants)

• LM7121IM5/NOPB
• LM7121IM5X/NOPB

These parts share the same base product number and manufacturer, maintaining full design compatibility. However, electrical performance differs: slew rate reduces to 520 V/µs, gain bandwidth product decreases to 105 MHz, and maximum supply voltage is limited to 11 V compared to the original 33 V specification.

Category 2: Analog Devices LT1815 Series (Cross-Manufacturer Alternatives)

• LT1815CS5#TR
• LT1815CS5#TRMPBF
• LT1815CS5#TRPBF
• LT1815IS5#TRMPBF

These parts provide enhanced electrical performance with slew rate of 1500 V/µs and gain bandwidth product of 220 MHz, exceeding the original LM7121IM5 specifications. Operating temperature range varies by variant: LT1815CS5 variants operate from 0°C to 70°C, while LT1815IS5#TRMPBF operates from -40°C to 85°C, matching the original temperature range. Minimum supply voltage is reduced to 2.5 V, and maximum supply voltage is limited to 11 V.

Parameter Comparison

Engineering Selection Recommendations

For designs requiring extended supply voltage range (up to 33 V): The LM7121IM5 original specification cannot be fully replicated by available substitutes, as all listed alternatives limit maximum supply voltage to 11 V. Designs dependent on the 33 V maximum specification require alternative sourcing strategies outside this substitute list.

For designs operating within 4.5 V to 11 V supply range with -40°C to 85°C temperature requirements: LM7121IM5/NOPB and LM7121IM5X/NOPB provide direct manufacturer compatibility with identical packaging and pinout. These parts maintain Active product status with substantial inventory availability (189,065 and 4,028 units respectively). Electrical performance is reduced compared to the original, with slew rate of 520 V/µs and gain bandwidth product of 105 MHz.

For designs requiring enhanced electrical performance within 4.5 V to 11 V supply range with -40°C to 85°C temperature requirements: LT1815IS5#TRMPBF (Analog Devices) provides superior slew rate (1500 V/µs) and gain bandwidth product (220 MHz) while maintaining the full -40°C to 85°C operating temperature range. This part carries Active product status with 2,409 units in inventory. Package compatibility is maintained at SOT-23-5 level, though the variant is specified as TSOT-23-5 (thin).

For designs operating within 0°C to 70°C temperature range: LT1815CS5 variants (LT1815CS5#TR, LT1815CS5#TRMPBF, LT1815CS5#TRPBF) offer enhanced performance with slew rate of 1500 V/µs and gain bandwidth product of 220 MHz. These parts are suitable only for applications not requiring the extended -40°C to 85°C temperature range. Inventory availability ranges from 1,012 to 2,180 units.

All substitute parts maintain ROHS3 compliance, MSL Level 1 rating, and EAR99 export classification consistent with the original part.

Frequently Asked Questions (FAQ)

Q: Can LM7121IM5/NOPB be used as a direct replacement for LM7121IM5 in all applications?

A: LM7121IM5/NOPB shares identical packaging (SOT-23-5), pinout, and operating temperature range (-40°C to 85°C) with the original LM7121IM5. However, electrical performance differs significantly: slew rate reduces from 1300 V/µs to 520 V/µs, and gain bandwidth product decreases from 175 MHz to 105 MHz. Additionally, maximum supply voltage is limited to 11 V instead of 33 V. Substitution is valid only for applications where these reduced specifications are acceptable.

Q: What is the difference between LT1815CS5 and LT1815IS5 variants?

A: The primary difference is operating temperature range. LT1815CS5 variants operate from 0°C to 70°C, while LT1815IS5#TRMPBF operates from -40°C to 85°C. All other electrical specifications are identical: slew rate of 1500 V/µs, gain bandwidth product of 220 MHz, input bias current of 2 µA, and input offset voltage of 200 µV. Selection depends on the required temperature range for the application.

Q: Are LT1815 parts pin-compatible with LM7121IM5?

A: Yes, all LT1815 variants use the same SOT-23-5 package pinout as the LM7121IM5. However, the LT1815 is specified as TSOT-23-5 (thin variant), which may have slightly different physical dimensions. PCB layout and component placement should be verified for mechanical clearance, though electrical pin assignments are identical.

Q: Why does the LM7121IM5 have a maximum supply voltage of 33 V while substitutes are limited to 11 V?

A: This is a fundamental design difference between the LM7121 and LT1815 architectures. The LM7121IM5 was designed to operate across a wider supply voltage range. No substitute parts in this list support the full 33 V maximum specification. Applications requiring 33 V operation cannot use these substitutes.

Q: What is the significance of the /NOPB and #TRMPBF suffixes in part numbers?

A: /NOPB indicates "No Plumbum" (lead-free) RoHS compliance from Texas Instruments. #TRMPBF indicates Tape & Reel packaging with lead-free termination from Analog Devices. Both designations confirm ROHS3 compliance and lead-free manufacturing. The #TR suffix without MPBF indicates standard Tape & Reel packaging. These suffixes do not affect electrical functionality.

Q: Can LM7121IM5X/NOPB be used interchangeably with LM7121IM5/NOPB?

A: Yes, both parts share identical electrical specifications, packaging, and operating temperature range. The "X" designation in LM7121IM5X/NOPB indicates a manufacturing variant or extended qualification level from Texas Instruments. Both are suitable substitutes for the original LM7121IM5 within the same electrical and thermal constraints.

Q: Which substitute part offers the best overall performance improvement?

A: LT1815IS5#TRMPBF provides the highest performance improvement with slew rate of 1500 V/µs (versus 1300 V/µs original) and gain bandwidth product of 220 MHz (versus 175 MHz original). It also maintains the full -40°C to 85°C operating temperature range. Input offset voltage is significantly lower at 200 µV compared to 900 µV. The trade-off is a reduced maximum supply voltage of 11 V instead of 33 V.

Q: Is inventory availability a factor in selecting a substitute?

A: Yes, inventory levels vary significantly. LM7121IM5/NOPB has the highest availability at 189,065 units. LT1815IS5#TRMPBF has 2,409 units, LT1815CS5#TRMPBF has 2,180 units, and LT1815CS5#TRPBF has 1,988 units. For high-volume production, LM7121IM5/NOPB offers the most reliable supply, though with reduced electrical performance compared to LT1815 alternatives.