MIC37139-1.8BS TR Equivalent & Substitute Parts

Part Overview

The MIC37139-1.8BS TR is a linear voltage regulator IC from Microchip Technology, designed to deliver a fixed 1.8V output at 1.5A in a SOT-223-3 surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The regulator provides over-current, over-temperature, and reverse polarity protection, operating across the industrial temperature range of -40°C to 125°C.

Substiute Parts

MIC37139-1.8BS TR

Microchip TechnologyIn Stock: 5448MIC37139-1.8BS TR Datasheet

Current PartRFQ

ADP3339AKCZ-1.8-RL

Analog Devices Inc.In Stock: 1459ADP3339AKCZ-1.8-RL Datasheet

MFR RecommendedRFQ

LM1117MP-1.8/NOPB

Texas InstrumentsIn Stock: 21684LM1117MP-1.8/NOPB Datasheet

MFR RecommendedRFQ

LM1117MPX-1.8/NOPB

Texas InstrumentsIn Stock: 55489LM1117MPX-1.8/NOPB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MIC37139-1.8BS TR are selected based on the following critical parameters that must align for functional equivalence:

• Fixed output voltage of 1.8V
• Positive output configuration
• SOT-223-3 package compatibility
• Surface mount technology
• Over-current and over-temperature protection
• Operating temperature range support

The substitute parts are grouped into two categories based on output current capability and input voltage specifications:

Group 1: Full Current Equivalents (1.5A Output) Parts meeting or exceeding the 1.5A output current specification with compatible input voltage ratings.

Group 2: Reduced Current Alternatives (800mA Output) Parts with lower output current ratings (800mA) suitable for applications where full 1.5A capacity is not required.

Parameter Comparison

Engineering Selection Recommendations

ADP3339AKCZ-1.8-RL (Analog Devices Inc.) This part provides the closest electrical match to the MIC37139-1.8BS TR, delivering 1.5A output current with a maximum input voltage of 6V and superior dropout voltage performance (0.48V @ 1.5A). The ADP3339AKCZ-1.8-RL is ROHS3 compliant and carries the anyCAP® series designation. However, its operating temperature range is limited to -40°C to 85°C, which is narrower than the original part. The product status is "Not For New Designs," indicating limited long-term availability. This substitute is suitable for applications where the reduced temperature range is acceptable and RoHS compliance is required.

LM1117MP-1.8/NOPB and LM1117MPX-1.8/NOPB (Texas Instruments) Both Texas Instruments LM1117 variants are active products with ROHS3 compliance and full industrial temperature range support (-40°C to 125°C for the original, 0°C to 125°C for these parts). These parts accept input voltages up to 15V, providing greater input voltage flexibility. However, they deliver only 800mA output current, which is 53% of the MIC37139-1.8BS TR specification. The dropout voltage is higher at 1.2V @ 800mA. These substitutes are appropriate for applications where output current requirements do not exceed 800mA and the higher input voltage tolerance is beneficial. The LM1117MPX-1.8/NOPB variant has significantly higher inventory availability (55,400 pcs) compared to the LM1117MP-1.8/NOPB (21,650 pcs).

Frequently Asked Questions (FAQ)

Q: Can the ADP3339AKCZ-1.8-RL be used as a direct replacement for the MIC37139-1.8BS TR? A: The ADP3339AKCZ-1.8-RL is electrically compatible for applications operating within -40°C to 85°C. It matches the 1.5A output current and 1.8V fixed output voltage. The primary limitation is the narrower operating temperature range; applications requiring operation above 85°C are not suitable for this substitute.

Q: Why do the LM1117 variants have lower output current ratings? A: The LM1117MP-1.8/NOPB and LM1117MPX-1.8/NOPB are designed for 800mA maximum output current, which is a different product tier within the LM1117 family. These parts are suitable only for applications where load current does not exceed 800mA.

Q: Are all substitute parts RoHS compliant? A: The ADP3339AKCZ-1.8-RL and both LM1117 variants are ROHS3 compliant. The original MIC37139-1.8BS TR is RoHS non-compliant. If RoHS compliance is a design requirement, any of the three substitutes meet this criterion.

Q: What is the package compatibility between the main part and substitutes? A: All parts use SOT-223 surface mount packaging. The MIC37139-1.8BS TR specifies SOT-223-3, while the substitutes specify SOT-223 or SOT-223-3. These designations refer to the same three-pin package configuration and are mechanically and electrically compatible.

Q: Which substitute offers the best dropout voltage performance? A: The ADP3339AKCZ-1.8-RL provides the lowest dropout voltage at 0.48V @ 1.5A, compared to 0.5V @ 1.5A for the original part. The LM1117 variants have higher dropout voltage at 1.2V @ 800mA, which may impact efficiency in low-input-voltage applications.

Q: Can I use an LM1117 variant if my application requires 1.5A output? A: No. The LM1117MP-1.8/NOPB and LM1117MPX-1.8/NOPB are rated for maximum 800mA output current. Using these parts in applications requiring 1.5A will result in thermal stress, potential device failure, and loss of protection features.

Q: What is the difference between LM1117MP-1.8/NOPB and LM1117MPX-1.8/NOPB? A: Both parts are electrically identical with the same electrical specifications and operating characteristics. The primary difference is inventory availability, with the LM1117MPX-1.8/NOPB having significantly higher stock levels (55,400 pcs vs. 21,650 pcs).