LM4128BMF-1.8 Equivalent & Substitute Parts

Part Overview

The LM4128BMF-1.8 is a Series Voltage Reference IC from Texas Instruments, delivering a fixed 1.8V output with ±0.2% tolerance in a SOT-23-5 surface mount package. This precision voltage reference is designed for low-power applications requiring stable reference voltages across industrial temperature ranges (-40°C to 125°C). The main part is currently listed as obsolete, making equivalent substitute parts necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	1.8V
Output Current	20 mA
Voltage Tolerance	±0.2%
Temperature Coefficient	75 ppm/°C
Noise (0.1Hz to 10Hz)	170 µVp-p
Input Voltage Range	2.2V ~ 5.5V
Supply Current	100 µA
Operating Temperature	-40°C ~ 125°C (TJ)
Package Type	SOT-23-5 (SC-74A, SOT-753)
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution for the LM4128BMF-1.8 is determined by strict equivalence across the following electrical and mechanical parameters:

Fixed output voltage of 1.8V
Output current capability of 20 mA
Voltage tolerance of ±0.2%
Temperature coefficient of 75 ppm/°C
Noise specification of 170 µVp-p (0.1Hz to 10Hz)
Input voltage range of 2.2V ~ 5.5V
Supply current of 100 µA
Operating temperature range of -40°C ~ 125°C
SOT-23-5 package configuration

All identified substitute parts maintain these electrical specifications and package requirements. Differences in product status, RoHS compliance, and automotive qualification do not affect functional equivalence but may influence selection based on application requirements and supply chain considerations.

Parameter Comparison

Part Number	Manufacturer	Product Status	Output Voltage	Tolerance	Temp Coeff	Input Range	Package	RoHS Status	Automotive Grade
LM4128BMF-1.8	Texas Instruments	Obsolete	1.8V	±0.2%	75 ppm/°C	2.2V ~ 5.5V	SOT-23-5	Non-compliant	No
LM4128BMF-1.8/NOPB	National Semiconductor	Active	1.8V	±0.2%	75 ppm/°C	2.2V ~ 5.5V	SOT-23-5	Not specified	No
LM4128BMFX-1.8/NOPB	Texas Instruments	Active	1.8V	±0.2%	75 ppm/°C	2.2V ~ 5.5V	SOT-23-5	ROHS3 Compliant	No
LM4128BQ1MF1.8/NOPB	Texas Instruments	Active	1.8V	±0.2%	75 ppm/°C	2.2V ~ 5.5V	SOT-23-5	ROHS3 Compliant	Yes (AEC-Q100)
LM4128BQ1MFX1.8/NOPB	Texas Instruments	Active	1.8V	±0.2%	75 ppm/°C	2.2V ~ 5.5V	SOT-23-5	ROHS3 Compliant	Yes (AEC-Q100)

Engineering Selection Recommendations

For applications requiring the LM4128BMF-1.8, the following selection criteria apply:

General Industrial Applications: LM4128BMFX-1.8/NOPB or LM4128BMF-1.8/NOPB are suitable. Both maintain active product status and full electrical equivalence. LM4128BMFX-1.8/NOPB offers ROHS3 compliance for designs with environmental regulatory requirements.

Automotive Applications: LM4128BQ1MF1.8/NOPB or LM4128BQ1MFX1.8/NOPB are required. Both carry AEC-Q100 automotive qualification and ROHS3 compliance, meeting automotive supply chain standards.

Legacy System Support: LM4128BMF-1.8/NOPB from National Semiconductor provides an active alternative when Texas Instruments variants are unavailable, maintaining identical electrical specifications and SOT-23-5 packaging.

All substitute parts are available in Tape & Reel packaging format, suitable for automated assembly processes.

Frequently Asked Questions (FAQ)

Q: Can LM4128BMFX-1.8/NOPB directly replace LM4128BMF-1.8 in existing designs?

A: Yes. Both parts deliver identical electrical performance: 1.8V fixed output, ±0.2% tolerance, 75 ppm/°C temperature coefficient, and SOT-23-5 package configuration. The primary difference is product status (active vs. obsolete) and RoHS compliance level.

Q: What is the difference between LM4128BQ1MF1.8/NOPB and LM4128BQ1MFX1.8/NOPB?

A: Both parts are electrically identical and carry AEC-Q100 automotive qualification. The difference lies in packaging format and supply chain designation. Selection depends on procurement requirements and assembly process compatibility.

Q: Are automotive-grade parts (AEC-Q100) suitable for non-automotive applications?

A: Yes. Automotive-qualified parts meet or exceed industrial specifications and can be used in general applications. However, cost considerations may favor non-automotive variants for non-automotive designs.

Q: Does the SOT-23-5 package remain consistent across all substitute parts?

A: Yes. All substitute parts use the SOT-23-5 package (SC-74A, SOT-753 designation), ensuring PCB layout and footprint compatibility without design modification.

Q: What inventory levels are available for each substitute part?

A: LM4128BQ1MF1.8/NOPB: 2141 pcs; LM4128BQ1MFX1.8/NOPB: 1123 pcs; LM4128BMFX-1.8/NOPB: 962 pcs; LM4128BMF-1.8/NOPB: 1026 pcs. Inventory levels are subject to change and should be verified at time of procurement.

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