Request Quote
(Ships tomorrow)
LP5951MF-1.8 Equivalent & Substitute Parts
Part Overview
The LP5951MF-1.8 is a linear voltage regulator IC manufactured by Texas Instruments, designed to deliver a fixed 1.8V output at 150mA in a SOT-23-5 surface mount package. This device functions as a positive fixed output regulator with integrated enable control and comprehensive protection features including over-current, over-temperature, and short-circuit protection.
The LP5951MF-1.8 carries an obsolete product status. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support ongoing production requirements for applications utilizing this regulator topology.
Substiute Parts
Key Parameters
| Parameter | Value | Unit |
|---|---|---|
| Output Voltage (Fixed) | 1.8 | V |
| Output Current | 150 | mA |
| Input Voltage (Maximum) | 5.5 | V |
| Dropout Voltage @ 150mA | 0.35 | V |
| Quiescent Current | 55 | µA |
| PSRR (100Hz to 10kHz) | 60dB ~ 50dB | dB |
| Operating Temperature Range | -40 to 125 | °C |
| Package Type | SOT-23-5 | — |
| Mounting Type | Surface Mount | — |
| Control Features | Enable | — |
| Protection Features | Over Current, Over Temperature, Short Circuit | — |
Substitute Part Grouping Explanation
Substitute parts for the LP5951MF-1.8 are classified based on strict adherence to the following electrical and mechanical parameters:
Primary Substitution Criteria:
- Fixed output voltage of 1.8V
- Output current capability of 150mA or greater
- Maximum input voltage of 5.5V or higher
- Surface mount package (SOT-23-5 or equivalent footprint)
- Enable control feature
- Operating temperature range encompassing -40°C to 125°C or compatible subset
Grouping Logic:
Group 1: Direct Parametric Equivalents (Texas Instruments LP5951 Series) Parts LP5951MF-1.8/NOPB and LP5951MFX-1.8/NOPB are parametrically identical to the main part, differing only in packaging format (Cut Tape vs. Tape & Reel) and product status (Active vs. Obsolete). These parts maintain identical electrical specifications and are the primary substitutes.
Group 2: Higher Current Capacity Substitutes (Rohm Semiconductor BU18 Series) Parts BU18SD2MG-MTR, BU18UB3WG-TR, and BU18UC3WG-TR provide output current capabilities ranging from 200mA to 360mA, exceeding the 150mA requirement. These parts maintain 1.8V fixed output and are suitable for applications requiring additional current headroom. BU18SD2MG-MTR is automotive-qualified (AEC-Q100). BU18UB3WG-TR and BU18UC3WG-TR carry "Not For New Designs" status.
Group 3: Microchip Technology MIC5306 and MIC5365 Series Parts MIC5306-1.8YD5-TR, MIC5365-1.8YD5-T5, and MIC5365-1.8YD5-TR deliver 150mA output current with improved quiescent current performance (25µA to 39µA vs. 55µA) and lower dropout voltage characteristics. All parts are Active status and RoHS3 compliant.
Group 4: ABLIC Inc. S-1135 Series Parts S-1135A18-M5T1U and S-1135D18-M5T1U provide 300mA output current with ultra-low quiescent current (1µA). Both parts carry Obsolete status and are suitable for low-power standby applications.
Parameter Comparison
| Part Number | Manufacturer | Output Voltage (V) | Output Current (mA) | Input Voltage Max (V) | Dropout @ 150mA (V) | Quiescent Current (µA) | Package | Product Status | RoHS Status |
|---|---|---|---|---|---|---|---|---|---|
| LP5951MF-1.8 | Texas Instruments | 1.8 | 150 | 5.5 | 0.35 | 55 | SOT-23-5 | Obsolete | Non-compliant |
| LP5951MF-1.8/NOPB | Texas Instruments | 1.8 | 150 | 5.5 | 0.35 | 55 | SOT-23-5 | Active | ROHS3 Compliant |
| LP5951MFX-1.8/NOPB | Texas Instruments | 1.8 | 150 | 5.5 | 0.35 | 55 | SOT-23-5 | Active | ROHS3 Compliant |
| BU18SD2MG-MTR | Rohm Semiconductor | 1.8 | 200 | 6.0 | 0.29 @ 100mA | 80 | 5-SSOP | Active | ROHS3 Compliant |
| BU18UB3WG-TR | Rohm Semiconductor | 1.8 | 360 | 3.6 | 0.32 @ 300mA | 90 | 5-SSOP | Not For New Designs | ROHS3 Compliant |
| BU18UC3WG-TR | Rohm Semiconductor | 1.8 | 300 | 5.5 | 0.32 @ 300mA | 90 | 5-SSOP | Not For New Designs | ROHS3 Compliant |
| MIC5306-1.8YD5-TR | Microchip Technology | 1.8 | 150 | 5.5 | 0.2 | 25 | TSOT-23-5 | Active | ROHS3 Compliant |
| MIC5365-1.8YD5-T5 | Microchip Technology | 1.8 | 150 | 5.5 | 0.38 | 39 | TSOT-23-5 | Active | ROHS3 Compliant |
| MIC5365-1.8YD5-TR | Microchip Technology | 1.8 | 150 | 5.5 | 0.38 | 39 | TSOT-23-5 | Active | ROHS3 Compliant |
| S-1135A18-M5T1U | ABLIC Inc. | 1.8 | 300 | 5.5 | — | 1 | SOT-23-5 | Obsolete | ROHS3 Compliant |
| S-1135D18-M5T1U | ABLIC Inc. | 1.8 | 300 | 5.5 | — | 1 | SOT-23-5 | Obsolete | ROHS3 Compliant |
Engineering Selection Recommendations
For Direct Replacement (Identical Electrical Performance):
LP5951MF-1.8/NOPB and LP5951MFX-1.8/NOPB are the primary substitutes. Both parts are Active status and RoHS3 compliant, addressing the obsolescence of the original LP5951MF-1.8. These parts maintain identical output voltage, current, dropout voltage, and quiescent current specifications. Selection between these two variants depends on packaging requirements: LP5951MF-1.8/NOPB is supplied in Cut Tape format, while LP5951MFX-1.8/NOPB is supplied in Tape & Reel format.
For Applications Requiring Higher Current Capacity:
BU18UC3WG-TR provides 300mA output current while maintaining 5.5V maximum input voltage compatibility with the original part. This part is suitable for designs where current margin is required. However, this part carries "Not For New Designs" status. BU18SD2MG-MTR offers 200mA output current with Active status and automotive qualification (AEC-Q100), making it suitable for automotive applications requiring higher current than the original 150mA specification.
For Low-Power Applications:
MIC5306-1.8YD5-TR delivers superior quiescent current performance (25µA vs. 55µA) and lower dropout voltage (0.2V vs. 0.35V), making it optimal for battery-powered or low-standby-current applications. This part is Active status and RoHS3 compliant. MIC5365-1.8YD5-TR provides similar performance with slightly higher quiescent current (39µA) and is available in higher inventory quantities.
Compliance Considerations:
All recommended Active status substitutes are RoHS3 compliant. The original LP5951MF-1.8 is RoHS non-compliant. Migration to compliant alternatives (LP5951MF-1.8/NOPB, LP5951MFX-1.8/NOPB, or Microchip alternatives) is necessary for new designs and ongoing production to meet regulatory requirements.
Frequently Asked Questions (FAQ)
Q: Can LP5951MF-1.8/NOPB be used as a direct drop-in replacement for LP5951MF-1.8?
A: Yes. LP5951MF-1.8/NOPB is parametrically identical to LP5951MF-1.8, with identical output voltage (1.8V), output current (150mA), dropout voltage (0.35V @ 150mA), quiescent current (55µA), and operating temperature range (-40°C to 125°C). The primary difference is product status (Active vs. Obsolete) and RoHS compliance (ROHS3 Compliant vs. Non-compliant). No circuit modifications are required.
Q: What is the difference between LP5951MF-1.8/NOPB and LP5951MFX-1.8/NOPB?
A: Both parts are electrically identical. The difference is packaging format: LP5951MF-1.8/NOPB is supplied in Cut Tape (CT) & Digi-Reel® format, while LP5951MFX-1.8/NOPB is supplied in Tape & Reel (TR) format. Selection depends on assembly line requirements and tape specifications.
Q: Can MIC5306-1.8YD5-TR replace LP5951MF-1.8 in all applications?
A: MIC5306-1.8YD5-TR is electrically compatible with identical output voltage (1.8V), output current (150mA), and input voltage rating (5.5V). However, the package is TSOT-23-5 (thin SOT-23-5) rather than standard SOT-23-5. PCB footprint compatibility must be verified. MIC5306-1.8YD5-TR offers superior quiescent current (25µA vs. 55µA) and lower dropout voltage (0.2V vs. 0.35V), making it preferable for low-power applications.
Q: Are Rohm BU18 series parts suitable replacements?
A: Rohm BU18 series parts provide higher output current (200mA to 360mA) than the original 150mA specification. BU18SD2MG-MTR is Active status and automotive-qualified. BU18UB3WG-TR and BU18UC3WG-TR carry "Not For New Designs" status. These parts are suitable only if higher current capacity is required or acceptable in the application. BU18UB3WG-TR has a lower maximum input voltage (3.6V vs. 5.5V), which may limit compatibility.
Q: What is the significance of "Not For New Designs" status?
A: Parts marked "Not For New Designs" are in mature or declining production phases. While functionally operational, manufacturers do not recommend their use in new product designs. These parts may have limited availability or extended lead times. For new designs, Active status parts (LP5951MF-1.8/NOPB, LP5951MFX-1.8/NOPB, MIC5306-1.8YD5-TR, MIC5365-1.8YD5-TR) are preferred.
Q: How does quiescent current affect part selection?
A: Quiescent current (Iq) represents the regulator's internal current consumption when delivering zero load current. Lower quiescent current reduces power dissipation in standby or low-load conditions. MIC5306-1.8YD5-TR (25µA) and MIC5365-1.8YD5-TR (39µA) consume significantly less quiescent current than LP5951MF-1.8 (55µA). For battery-powered applications or designs with extended low-power modes, lower quiescent current parts provide extended runtime.
Q: What is dropout voltage and why does it matter?
A: Dropout voltage is the minimum difference between input and output voltage required for the regulator to maintain regulation at specified output current. Lower dropout voltage allows operation with lower input voltages or provides greater headroom for input voltage variations. MIC5306-1.8YD5-TR (0.2V @ 150mA) has superior dropout performance compared to LP5951MF-1.8 (0.35V @ 150mA), enabling operation in applications with tighter input voltage margins.
Q: Are ABLIC S-1135 series parts recommended for new designs?
A: S-1135A18-M5T1U and S-1135D18-M5T1U carry Obsolete status and are not recommended for new designs. These parts offer ultra-low quiescent current (1µA) and higher output current (300mA), but obsolescence status indicates declining availability. For new designs requiring low quiescent current, Microchip MIC5306-1.8YD5-TR or MIC5365-1.8YD5-TR are preferred alternatives with Active status.
Q: What RoHS compliance status should be specified for new designs?
A: New designs should specify ROHS3 Compliant parts. The original LP5951MF-1.8 is RoHS non-compliant. All recommended Active status substitutes (LP5951MF-1.8/NOPB, LP5951MFX-1.8/NOPB, Microchip MIC5306 and MIC5365 series, Rohm BU18SD2MG-MTR) are ROHS3 compliant, meeting current regulatory requirements for electronic components.
Alternative Parts
SJ6012L2TP
Littelfuse Inc.
6 Alternative Parts
JMK107BBJ476MA-RE
Taiyo Yuden
10 Alternative Parts
GMK107BBJ475MA-T
Taiyo Yuden
5 Alternative Parts
SJ6020N2ARP
Littelfuse Inc.
3 Alternative Parts
SJ6025R2ATP
Littelfuse Inc.
4 Alternative Parts
2474-05L
API Delevan Inc.
1 Alternative Parts
4590R-684K
API Delevan Inc.
1 Alternative Parts
CM6560R-334
API Delevan Inc.
1 Alternative Parts
CM6460-104
API Delevan Inc.
1 Alternative Parts
5526-12
API Delevan Inc.
1 Alternative Parts