LM4128DMF-3.3 Equivalent & Substitute Parts

Part Overview

The LM4128DMF-3.3 is a Series Voltage Reference IC manufactured by Texas Instruments, providing a fixed 3.3V output with ±1% tolerance in a SOT-23-5 surface mount package. This part is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and production continuity. The device delivers 20 mA output current with a temperature coefficient of 100ppm/°C and operates across the industrial temperature range of -40°C to 125°C.

Substiute Parts

LM4128DMF-3.3

Texas InstrumentsIn Stock: 856LM4128DMF-3.3 Datasheet

Current PartRFQ

LM4128DMF-3.3/NOPB

Texas InstrumentsIn Stock: 4072LM4128DMF-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LM4128DMFX-3.3/NOPB

Texas InstrumentsIn Stock: 902LM4128DMFX-3.3/NOPB Datasheet

Parametric EquivalentRFQ

LM4128DQ1MF3.3/NOPB

Texas InstrumentsIn Stock: 3010LM4128DQ1MF3.3/NOPB Datasheet

Parametric EquivalentRFQ

LM4128DQ1MFX3.3/NOPB

Texas InstrumentsIn Stock: 851LM4128DQ1MFX3.3/NOPB Datasheet

Parametric EquivalentRFQ

MAX6037AAUK33+T

Analog Devices Inc./Maxim IntegratedIn Stock: 3575MAX6037AAUK33+T Datasheet

MFR RecommendedRFQ

MAX6037BAUK33+T

Analog Devices Inc./Maxim IntegratedIn Stock: 1044MAX6037BAUK33+T Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LM4128DMF-3.3 is determined by the following critical parameters:

Electrical Compatibility Criteria:

• Fixed output voltage of 3.3V
• Output current capability of 20 mA or greater
• Input voltage range of 3.7V to 5.5V or compatible range
• Tolerance specification of ±1% or better
• Temperature coefficient of 100ppm/°C or lower
• Operating temperature range of -40°C to 125°C or wider

Mechanical Compatibility Criteria:

• Surface mount package type
• SOT-23-5 package configuration (SC-74A, SOT-753)

Compliance Criteria:

• RoHS3 compliance preferred for new designs
• Moisture Sensitivity Level 1 (Unlimited)

Substitute parts are grouped into two categories: parametric equivalents from Texas Instruments (direct replacements with identical electrical specifications) and manufacturer-recommended alternatives from Analog Devices Inc./Maxim Integrated (functionally compatible with enhanced performance characteristics).

Parameter Comparison

Engineering Selection Recommendations

Texas Instruments LM4128 Series Parametric Equivalents:

The LM4128DMF-3.3/NOPB, LM4128DMFX-3.3/NOPB, LM4128DQ1MF3.3/NOPB, and LM4128DQ1MFX3.3/NOPB represent direct parametric replacements for the obsolete LM4128DMF-3.3. All four variants maintain identical electrical specifications: 3.3V fixed output, 20 mA output current, ±1% tolerance, 100ppm/°C temperature coefficient, and 310µVp-p noise performance. All are active products with ROHS3 compliance.

The primary distinction among these variants is automotive qualification. The LM4128DQ1MF3.3/NOPB and LM4128DQ1MFX3.3/NOPB carry AEC-Q100 automotive qualification, making them suitable for automotive and high-reliability applications. The "X" suffix variants (DMFX and DQ1MFX) indicate extended temperature or performance screening. For standard industrial applications, LM4128DMF-3.3/NOPB or LM4128DMFX-3.3/NOPB are appropriate selections.

Analog Devices/Maxim MAX6037 Series Alternatives:

The MAX6037AAUK33+T and MAX6037BAUK33+T are manufacturer-recommended alternatives offering enhanced performance characteristics. Both maintain the 3.3V fixed output and SOT-23-5 package compatibility. Key differences include reduced output current (5 mA versus 20 mA), improved tolerance specifications (±0.2% and ±0.3% respectively versus ±1%), significantly lower temperature coefficients (25ppm/°C and 50ppm/°C versus 100ppm/°C), and substantially reduced noise performance (19µVp-p versus 310µVp-p).

Selection of MAX6037 variants is appropriate when applications require superior voltage stability, lower noise, or tighter tolerance specifications. The lower output current capability (5 mA) must be verified against circuit requirements. Both MAX6037 variants are ROHS3 compliant and active products.

Compliance and Status Considerations:

All recommended substitutes are active products with ROHS3 compliance, addressing the obsolescence and non-compliance status of the original LM4128DMF-3.3. For new designs, selection should prioritize active products with ROHS3 compliance. Automotive applications must specify the AEC-Q100 qualified variants (LM4128DQ1MF3.3/NOPB or LM4128DQ1MFX3.3/NOPB).

Frequently Asked Questions (FAQ)

Q: Can I directly replace LM4128DMF-3.3 with LM4128DMF-3.3/NOPB?

A: Yes. The LM4128DMF-3.3/NOPB is a parametric equivalent with identical electrical specifications and the same SOT-23-5 package. The primary advantage is active product status and ROHS3 compliance. The "/NOPB" designation indicates lead-free, RoHS-compliant manufacturing.

Q: What is the difference between LM4128DMFX-3.3/NOPB and LM4128DMF-3.3/NOPB?

A: Both parts are parametrically identical with 3.3V output, 20 mA current, ±1% tolerance, and 100ppm/°C temperature coefficient. The "X" suffix indicates extended screening or performance verification. Selection between these variants depends on specific application requirements and supplier availability.

Q: Are the automotive-qualified variants (LM4128DQ1MF3.3/NOPB) required for all applications?

A: Automotive qualification (AEC-Q100) is required only for automotive and high-reliability applications. For standard industrial and consumer applications, the non-automotive variants (LM4128DMF-3.3/NOPB or LM4128DMFX-3.3/NOPB) are appropriate and typically offer better availability.

Q: Can I use MAX6037AAUK33+T as a direct replacement?

A: MAX6037AAUK33+T is functionally compatible but not a direct replacement. While both provide 3.3V output in SOT-23-5 packages, the MAX6037 delivers only 5 mA output current compared to 20 mA for the LM4128. Use MAX6037 only if circuit current requirements do not exceed 5 mA. The MAX6037 offers superior voltage stability and lower noise, making it suitable for precision applications.

Q: What are the key differences between MAX6037AAUK33+T and MAX6037BAUK33+T?

A: Both parts provide 3.3V output, 5 mA current, and SOT-23-5 packaging. The primary differences are tolerance (±0.2% for AAUK33 versus ±0.3% for BAUK33) and temperature coefficient (25ppm/°C for AAUK33 versus 50ppm/°C for BAUK33). Select MAX6037AAUK33+T for applications requiring tighter voltage stability; select MAX6037BAUK33+T for cost-optimized designs with relaxed stability requirements.

Q: Is the SOT-23-5 package identical across all substitute parts?

A: Yes. All substitute parts use the SC-74A/SOT-753 package designation, which is the SOT-23-5 configuration. Pin-to-pin compatibility is maintained across all listed substitutes, allowing direct PCB footprint compatibility.

Q: Why is the original LM4128DMF-3.3 marked as obsolete?

A: The LM4128DMF-3.3 is obsolete due to RoHS non-compliance and product lifecycle discontinuation by Texas Instruments. Active equivalents with ROHS3 compliance (LM4128DMF-3.3/NOPB and variants) are available as direct replacements.

Q: What is the impact of higher supply current in MAX6037 variants (275µA versus 100µA)?

A: The MAX6037 series draws 275µA supply current compared to 100µA for LM4128 variants. This 2.75x increase in quiescent current consumption must be evaluated in battery-powered or power-constrained applications. For line-powered applications, this difference is typically negligible.

Q: Can I mix LM4128 and MAX6037 variants in the same design?

A: Mixing is not recommended within the same circuit unless the different output current capabilities and noise characteristics are intentionally leveraged for different functional blocks. Standardizing on a single variant simplifies procurement, inventory management, and design documentation.