LM4128DMFX-1.8 Equivalent & Substitute Parts

Part Overview

The LM4128DMFX-1.8 is a Series Voltage Reference IC manufactured by Texas Instruments, designed to provide a fixed 1.8V output with ±1% tolerance. This component operates as a precision micropower voltage reference in the Power Management (PMIC) category, housed in a SOT-23-5 surface mount package. The main part number is currently listed as Obsolete, making identification of active equivalent and substitute parts essential for ongoing design support and procurement.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	1.8V
Output Current	20 mA
Tolerance	±1%
Temperature Coefficient	100 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 / Case	SC-74A, SOT-753
Supplier Device Package	SOT-23-5
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution of the LM4128DMFX-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
Tolerance specification of ±1%
Temperature coefficient of 100 ppm/°C
Noise performance 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
Surface mount mounting type

All identified substitute parts maintain these electrical and mechanical specifications. Differences in product status, packaging format (Bulk vs. Tape & Reel), RoHS compliance, and automotive qualification do not affect functional equivalence but may impact procurement and application suitability.

Parameter Comparison

Part Number	Manufacturer	Product Status	Output Voltage	Output Current	Tolerance	Temp Coefficient	Input Voltage	Supply Current	Operating Temp	Package	RoHS Status	Automotive Grade
LM4128DMFX-1.8	Texas Instruments	Obsolete	1.8V	20 mA	±1%	100 ppm/°C	2.2V ~ 5.5V	100 µA	-40°C ~ 125°C	SOT-23-5	Non-compliant	No
LM4128DMF-1.8/NOPB	National Semiconductor	Active	1.8V	20 mA	±1%	100 ppm/°C	2.2V ~ 5.5V	100 µA	-40°C ~ 125°C	SOT-23-5	Not specified	No
LM4128DMFX-1.8/NOPB	Texas Instruments	Active	1.8V	20 mA	±1%	100 ppm/°C	2.2V ~ 5.5V	100 µA	-40°C ~ 125°C	SOT-23-5	ROHS3 Compliant	No
LM4128DQ1MF1.8/NOPB	Texas Instruments	Active	1.8V	20 mA	±1%	100 ppm/°C	2.2V ~ 5.5V	100 µA	-40°C ~ 125°C	SOT-23-5	ROHS3 Compliant	Yes (AEC-Q100)
LM4128DQ1MFX1.8/NOPB	Texas Instruments	Active	1.8V	20 mA	±1%	100 ppm/°C	2.2V ~ 5.5V	100 µA	-40°C ~ 125°C	SOT-23-5	ROHS3 Compliant	Yes (AEC-Q100)

Engineering Selection Recommendations

For applications requiring direct replacement of the obsolete LM4128DMFX-1.8, the LM4128DMFX-1.8/NOPB is the primary substitute. This part maintains identical electrical specifications and packaging while offering Active product status and ROHS3 compliance.

For automotive applications or designs requiring AEC-Q100 qualification, LM4128DQ1MF1.8/NOPB and LM4128DQ1MFX1.8/NOPB are suitable alternatives. Both parts carry automotive-grade designation and meet ROHS3 requirements.

The LM4128DMF-1.8/NOPB, manufactured by National Semiconductor, provides functional equivalence with Active status but lacks specified RoHS compliance documentation.

Selection between Tape & Reel and Bulk packaging formats depends on procurement volume and assembly requirements; electrical performance remains identical across packaging options.

Frequently Asked Questions (FAQ)

Q: Can LM4128DQ1MF1.8/NOPB replace LM4128DMFX-1.8 in non-automotive applications?

A: Yes. The LM4128DQ1MF1.8/NOPB maintains all electrical and mechanical specifications required for functional equivalence. Automotive qualification does not restrict use in non-automotive designs.

Q: What is the difference between Tape & Reel and Bulk packaging?

A: Tape & Reel packaging is supplied on continuous tape suitable for automated assembly equipment. Bulk packaging is supplied loose. Electrical performance and component specifications are identical; packaging format affects only handling and assembly processes.

Q: Is the LM4128DMF-1.8/NOPB from National Semiconductor fully compatible?

A: Yes, the LM4128DMF-1.8/NOPB is electrically and mechanically equivalent. It maintains the same output voltage, current, tolerance, temperature coefficient, and SOT-23-5 package configuration. RoHS compliance status is not specified for this variant.

Q: Why is the original LM4128DMFX-1.8 marked as Obsolete?

A: Product status reflects manufacturer lifecycle decisions. Active equivalents with identical specifications are available, ensuring design continuity without functional compromise.

Q: Are all substitute parts ROHS3 compliant?

A: No. The LM4128DMF-1.8/NOPB does not specify RoHS compliance status. All Texas Instruments variants (LM4128DMFX-1.8/NOPB, LM4128DQ1MF1.8/NOPB, LM4128DQ1MFX1.8/NOPB) are ROHS3 compliant.

Q: Can I use LM4128DQ1MFX1.8/NOPB in place of LM4128DMFX-1.8/NOPB?

A: Yes. Both parts are electrically identical with matching SOT-23-5 packaging. The DQ1 variant includes automotive qualification; this additional certification does not prevent use in standard industrial applications.

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