LP3990MF-1.2 Equivalent & Substitute Parts

Part Overview

The LP3990MF-1.2 is a linear voltage regulator IC from Texas Instruments, delivering a fixed 1.2V output at 150mA in a SOT-23-5 surface mount package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. The regulator features enable control, over-temperature and short-circuit protection, and operates across the industrial temperature range of -40°C to 85°C. Substitute parts must maintain the core electrical specifications: 1.2V fixed output, 150mA output current capability, and compatible packaging for direct board-level replacement.

Key Parameters

Parameter	Value	Unit
Output Voltage (Fixed)	1.2	V
Output Current	150	mA
Input Voltage (Max)	6	V
Voltage Dropout (Max)	0.2	V @ 150mA
Quiescent Current	80	µA
Operating Temperature	-40 to 85	°C
Package Type	SOT-23-5
Mounting Type	Surface Mount

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Output voltage: 1.2V fixed (exact match required)
Output current: minimum 150mA (equal or greater acceptable)
Input voltage maximum: 6V or higher
Package compatibility: SOT-23-5, SOT-25, or TSOT-23-5 (all pin-compatible surface mount variants)
Mounting type: Surface mount only
Control features: Enable function required
Protection: Over-temperature protection mandatory

Grouping Logic: Substitute parts are organized by output current capability and package variant. Parts with 150mA output current in SOT-23-5 or TSOT-23-5 packages represent direct pin-for-pin replacements. Parts with higher output current (200mA, 300mA, 600mA) in SOT-25 packages are functional equivalents suitable for applications requiring increased current headroom, though board layout modifications may be necessary due to package differences.

Parameter Comparison

Part Number	Manufacturer	Output Voltage	Output Current	Voltage Dropout	Quiescent Current	Package	Product Status	RoHS Status
LP3990MF-1.2	Texas Instruments	1.2V	150mA	0.2V @ 150mA	80µA	SOT-23-5	Obsolete	Non-compliant
LP3990MF-1.2/NOPB	Texas Instruments	1.2V	150mA	0.2V @ 150mA	80µA	SOT-23-5	Active	ROHS3 Compliant
LP3990MFX-1.2/NOPB	Texas Instruments	1.2V	150mA	0.2V @ 150mA	80µA	SOT-23-5	Active	ROHS3 Compliant
MIC5317-1.2YD5-T5	Microchip Technology	1.2V	150mA	0.38V @ 150mA	39µA	TSOT-23-5	Active	ROHS3 Compliant
MIC5365-1.2YD5-TR	Microchip Technology	1.2V	150mA	0.38V @ 150mA	39µA	TSOT-23-5	Active	ROHS3 Compliant
S-1315A12-M5T1U3	ABLIC Inc.	1.2V	200mA	0.665V @ 200mA	1µA	SOT-23-5	Active	ROHS3 Compliant
S-1315B12-M5T1U3	ABLIC Inc.	1.2V	200mA	0.665V @ 200mA	1µA	SOT-23-5	Active	ROHS3 Compliant
BU12SD2MG-MTR	Rohm Semiconductor	1.2V	200mA	0.55V @ 100mA	80µA	5-SSOP	Active	ROHS3 Compliant
AP7311-12WG-7	Diodes Incorporated	1.2V	150mA	0.3V @ 150mA	75µA	SOT-25	Active	ROHS3 Compliant
AP7335-12WG-7	Diodes Incorporated	1.2V	300mA	0.3V @ 300mA	80µA	SOT-25	Active	ROHS3 Compliant
AP7365-12WG-7	Diodes Incorporated	1.2V	600mA	0.6V @ 600mA	80µA	SOT-25	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Pin-for-Pin Replacements (Highest Compatibility):

LP3990MF-1.2/NOPB and LP3990MFX-1.2/NOPB from Texas Instruments are identical electrical equivalents to the obsolete LP3990MF-1.2, with the primary distinction being product status (active vs. obsolete) and RoHS compliance (ROHS3 compliant vs. non-compliant). Both maintain the same SOT-23-5 package, 150mA output current, and 0.2V dropout specification. LP3990MF-1.2/NOPB is available in cut tape and digi-reel packaging with 20,200 units in stock. LP3990MFX-1.2/NOPB is available in tape and reel format with 4,375 units in stock. Selection between these two should be based on packaging requirements and supply chain availability.

Pin-Compatible Alternatives (TSOT-23-5 Package):

MIC5317-1.2YD5-T5 and MIC5365-1.2YD5-TR from Microchip Technology are functionally equivalent in SOT-23-5 thin package variants. Both deliver 150mA output current at 1.2V with improved quiescent current performance (39µA vs. 80µA) and superior PSRR (80dB to 65dB across 1kHz to 10kHz). MIC5365-1.2YD5-TR operates with a maximum input voltage of 5.5V compared to 6V for the original part, requiring verification in applications with higher input voltages. Both are ROHS3 compliant and active products.

Higher Current Capability Alternatives (SOT-25 Package):

AP7311-12WG-7 from Diodes Incorporated provides 150mA output current in SOT-25 package with 0.3V dropout at rated current. AP7335-12WG-7 and AP7365-12WG-7 offer 300mA and 600mA output current respectively, suitable for applications requiring increased current headroom. These parts require PCB layout modifications due to package change from SOT-23-5 to SOT-25, but maintain the 1.2V output voltage and 6V maximum input specification. All three are ROHS3 compliant and active products.

Extended Temperature Range Option:

BU12SD2MG-MTR from Rohm Semiconductor is an automotive-grade part (AEC-Q100 qualified) with 200mA output current in 5-SSOP package, operating to 105°C maximum junction temperature. This part is suitable for applications requiring extended temperature performance beyond the standard -40°C to 85°C range.

Selection Criteria Summary:

For direct replacement with maximum compatibility: LP3990MF-1.2/NOPB or LP3990MFX-1.2/NOPB
For improved quiescent current performance: MIC5317-1.2YD5-T5 or MIC5365-1.2YD5-TR
For higher current capability: AP7311-12WG-7, AP7335-12WG-7, or AP7365-12WG-7
For automotive applications: BU12SD2MG-MTR

All recommended substitutes are ROHS3 compliant and active products with established supply availability.

Frequently Asked Questions (FAQ)

Q: Can LP3990MF-1.2/NOPB be used as a direct replacement for the obsolete LP3990MF-1.2?

A: Yes. LP3990MF-1.2/NOPB is electrically and mechanically identical to the obsolete part, with identical SOT-23-5 packaging, 150mA output current, 1.2V fixed output, and 0.2V dropout specification. The primary differences are product status (active vs. obsolete) and RoHS compliance (ROHS3 compliant). No design changes are required.

Q: What is the difference between LP3990MF-1.2/NOPB and LP3990MFX-1.2/NOPB?

A: Both parts are electrically identical with the same electrical specifications. The difference is packaging format: LP3990MF-1.2/NOPB is available in cut tape and digi-reel, while LP3990MFX-1.2/NOPB is supplied in tape and reel format. Selection depends on assembly line requirements and supply chain preferences.

Q: Are MIC5317-1.2YD5-T5 and MIC5365-1.2YD5-TR pin-compatible with the LP3990MF-1.2?

A: Yes, both Microchip parts use TSOT-23-5 packaging, which is pin-compatible with SOT-23-5. However, TSOT-23-5 is a thinner variant. Verify PCB footprint compatibility before substitution. Both parts deliver 150mA at 1.2V with superior quiescent current (39µA vs. 80µA).

Q: What is the key difference between MIC5317-1.2YD5-T5 and MIC5365-1.2YD5-TR?

A: Both parts are electrically identical with the same 150mA output current and 1.2V output voltage. The primary difference is packaging: MIC5317-1.2YD5-T5 is supplied in cut tape format, while MIC5365-1.2YD5-TR is supplied in tape and reel format. Additionally, MIC5365-1.2YD5-TR has a maximum input voltage of 5.5V compared to 6V for MIC5317-1.2YD5-T5.

Q: Can AP7311-12WG-7 replace LP3990MF-1.2 without PCB modifications?

A: AP7311-12WG-7 uses SOT-25 packaging instead of SOT-23-5, requiring PCB footprint changes. However, it maintains 150mA output current and 1.2V output voltage. The 0.3V dropout at 150mA is slightly higher than the original 0.2V. PCB layout modifications are necessary for this substitution.

Q: When should AP7335-12WG-7 or AP7365-12WG-7 be selected over AP7311-12WG-7?

A: AP7335-12WG-7 provides 300mA output current and AP7365-12WG-7 provides 600mA output current, compared to 150mA for AP7311-12WG-7. These higher-current variants are selected when the application requires increased current capacity beyond 150mA. All three maintain 1.2V output voltage and SOT-25 packaging, requiring identical PCB modifications.

Q: Is BU12SD2MG-MTR suitable for standard industrial applications?

A: BU12SD2MG-MTR is an automotive-grade part (AEC-Q100 qualified) with extended operating temperature to 105°C. While suitable for industrial applications, it is optimized for automotive environments. For standard industrial applications within -40°C to 85°C, other substitutes may offer better cost efficiency.

Q: What are the compliance and certification differences between substitute parts?

A: All recommended substitute parts are ROHS3 compliant and REACH unaffected. The original LP3990MF-1.2 is RoHS non-compliant. All parts carry EAR99 export classification and HTSUS code 8542.39.0001. Moisture sensitivity level is 1 (unlimited) for all parts.

Q: Which substitute offers the lowest quiescent current?

A: S-1315A12-M5T1U3 and S-1315B12-M5T1U3 from ABLIC Inc. offer the lowest quiescent current at 1µA, compared to 80µA for the original LP3990MF-1.2. These parts deliver 200mA output current in SOT-23-5 packaging with significantly reduced standby power consumption.

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