LP3990MF-2.8 Equivalent & Substitute Parts

Part Overview

The LP3990MF-2.8 is a linear voltage regulator IC from Texas Instruments, delivering a fixed 2.8V output at 150mA in a SOT-23-5 surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The device features enable control, over-temperature and short-circuit protection, and operates across -40°C to 85°C. Substitutes must maintain the 2.8V fixed output, positive output configuration, and SOT-23-5 package compatibility while meeting or exceeding the original specifications.

Key Parameters

Parameter	LP3990MF-2.8
Manufacturer	Texas Instruments
Product Status	Obsolete
Output Voltage (Fixed)	2.8V
Output Current	150mA
Input Voltage (Max)	6V
Voltage Dropout (Max)	0.2V @ 150mA
Quiescent Current	80 µA
Package	SOT-23-5
Operating Temperature	-40°C to 85°C
Control Features	Enable
Protection Features	Over Temperature, Short Circuit
RoHS Status	Non-compliant

Substitute Part Grouping Explanation

Substitution for the LP3990MF-2.8 is determined by the following critical parameters:

Fixed output voltage of 2.8V
Output current capability of 150mA or greater
Maximum input voltage of 6V or greater
Surface mount package compatibility (SOT-23-5 or equivalent pin-compatible packages)
Enable control feature
Operating temperature range of -40°C to 85°C or wider

Substitute parts are grouped into three categories based on output current capacity and package type:

Category 1: Direct Equivalents (150mA output) Parts with 150mA output current in SOT-23-5 packages, suitable for direct replacement in existing designs.

Category 2: Higher Current Alternatives (200mA–300mA output) Parts with increased output current capacity, compatible with SOT-23-5 or 5-SSOP packages, for designs requiring additional current headroom.

Category 3: Enhanced Current Capacity (300mA–600mA output) Parts with significantly higher output current in SOT-25 packages, for applications requiring greater power delivery.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Input Voltage (Max)	Dropout @ Rated Current	Quiescent Current	Package	Operating Temp	Product Status	RoHS Status
LP3990MF-2.8	Texas Instruments	2.8V	150mA	6V	0.2V @ 150mA	80 µA	SOT-23-5	-40°C to 85°C	Obsolete	Non-compliant
LP3990MF-2.8/NOPB	Texas Instruments	2.8V	150mA	6V	0.2V @ 150mA	80 µA	SOT-23-5	-40°C to 85°C	Active	ROHS3 Compliant
MIC5256-2.8YM5-TR	Microchip Technology	2.8V	150mA	6V	0.25V @ 150mA	150 µA	SOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
MIC5317-2.8YD5-T5	Microchip Technology	2.8V	150mA	6V	0.31V @ 150mA	39 µA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
MIC5317-2.8YM5-T5	Microchip Technology	2.8V	150mA	6V	0.31V @ 150mA	39 µA	SOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
BU28SD2MG-MTR	ROHM Semiconductor	2.8V	200mA	6V	0.15V @ 100mA	80 µA	5-SSOP	-40°C to 105°C	Active	ROHS3 Compliant
BU28UC3WG-TR	ROHM Semiconductor	2.8V	300mA	5.5V	0.22V @ 300mA	90 µA	5-SSOP	-40°C to 85°C	Not For New Designs	ROHS3 Compliant
MIC5318-2.8YD5-TR	Microchip Technology	2.8V	300mA	6V	0.2V @ 300mA	150 µA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant
AP7335-28WG-7	Diodes Incorporated	2.8V	300mA	6V	0.2V @ 300mA	80 µA	SOT-25	-40°C to 85°C	Active	ROHS3 Compliant
AP7365-28WG-7	Diodes Incorporated	2.8V	600mA	6V	0.4V @ 600mA	80 µA	SOT-25	-40°C to 85°C	Active	ROHS3 Compliant
MIC5232-2.8YD5-TR	Microchip Technology	2.8V	10mA	7V	0.3V @ 10mA	3 µA	TSOT-23-5	-40°C to 125°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Active Product Status, RoHS Compliant)

LP3990MF-2.8/NOPB is the primary direct substitute. It maintains identical electrical specifications to the original LP3990MF-2.8 while offering active product status and ROHS3 compliance. This part is available in Tape & Reel packaging with 6300 units in stock.

For 150mA Applications with Extended Temperature Range

MIC5256-2.8YM5-TR and MIC5317-2.8YM5-T5 provide 150mA output with operating temperatures to 125°C. Both are ROHS3 compliant and active products. MIC5317-2.8YM5-T5 offers lower quiescent current (39 µA vs. 150 µA) and superior PSRR performance (80dB–65dB vs. 60dB–45dB), beneficial for noise-sensitive applications.

For Increased Current Capacity (200mA–300mA)

BU28SD2MG-MTR delivers 200mA in a 5-SSOP package with automotive qualification (AEC-Q100) and extended temperature range to 105°C. MIC5318-2.8YD5-TR provides 300mA in TSOT-23-5 with superior PSRR (75dB–55dB) and active product status.

For High Current Applications (300mA–600mA)

AP7335-28WG-7 (300mA) and AP7365-28WG-7 (600mA) are SOT-25 packages from Diodes Incorporated, both active and ROHS3 compliant. These are suitable for designs requiring significantly higher current delivery than the original 150mA specification.

Avoid for New Designs

BU28UC3WG-TR is marked "Not For New Designs" despite active inventory and ROHS3 compliance. This part should be used only for legacy system maintenance.

Frequently Asked Questions (FAQ)

Q: Can LP3990MF-2.8/NOPB be used as a direct drop-in replacement?

A: Yes. LP3990MF-2.8/NOPB is electrically and mechanically identical to LP3990MF-2.8, with the same 2.8V output, 150mA current, SOT-23-5 package, and operating temperature range. The primary differences are active product status and ROHS3 compliance.

Q: What is the difference between SOT-23-5 and TSOT-23-5 packages?

A: TSOT-23-5 is a thin variant of SOT-23-5 with reduced height. Both are pin-compatible and functionally equivalent. Verify PCB footprint compatibility before substitution, as some designs may require the standard SOT-23-5 height.

Q: Can I use a higher current part like MIC5318-2.8YD5-TR (300mA) in place of LP3990MF-2.8 (150mA)?

A: Yes. Higher current capacity is a safe substitution provided the package is compatible with your PCB layout. MIC5318-2.8YD5-TR maintains the same 2.8V output and 6V maximum input voltage, with improved PSRR and active product status.

Q: Why is BU28UC3WG-TR marked "Not For New Designs"?

A: This designation indicates the manufacturer recommends against using this part in new product development. While it remains in inventory and is ROHS3 compliant, alternative parts with active status are preferred for long-term reliability and support.

Q: What is the impact of different dropout voltages on circuit performance?

A: Dropout voltage determines the minimum input-to-output voltage differential required for regulation. LP3990MF-2.8 specifies 0.2V @ 150mA. Substitutes with higher dropout (e.g., MIC5317 at 0.31V) require proportionally higher input voltage to maintain stable output. Verify your input voltage margin before selecting a substitute with increased dropout.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. The original LP3990MF-2.8 is non-compliant. If RoHS compliance is required for your application, select from active products only.

Q: Can MIC5232-2.8YD5-TR (10mA) be used as a substitute?

A: No. MIC5232-2.8YD5-TR is rated for only 10mA output current, insufficient for applications requiring the original 150mA specification. This part is suitable only for low-power auxiliary supply applications.

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