LP3990SD-1.5 Equivalent & Substitute Parts

Part Overview

The LP3990SD-1.5 is a linear voltage regulator IC from Texas Instruments, delivering a fixed positive 1.5V output at 150mA in a 6-WSON (3x3) surface mount package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

The LP3990SD-1.5 integrates enable control, over-temperature protection, and short-circuit protection. It operates across the industrial temperature range of -40°C to 85°C with a maximum input voltage of 6V and a dropout voltage of 0.2V at full load current.

Substiute Parts

LP3990SD-1.5

Texas InstrumentsIn Stock: 762LP3990SD-1.5 Datasheet

Current PartRFQ

LP3990SD-1.5/NOPB

Texas InstrumentsIn Stock: 3779LP3990SD-1.5/NOPB Datasheet

DirectRFQ

LP5900SD-1.5/NOPB

Texas InstrumentsIn Stock: 2307LP5900SD-1.5/NOPB Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LP3990SD-1.5 are classified based on electrical and mechanical compatibility:

Direct Equivalent (LP3990SD-1.5/NOPB): Identical electrical specifications and package footprint. Differs only in product status (Active vs. Obsolete) and RoHS compliance level. This part maintains 100% pin-for-pin and functional compatibility.

Parametric Equivalent (LP5900SD-1.5/NOPB): Meets the core functional requirements of fixed 1.5V output at 150mA with identical control and protection features. Key differences include:

• Input voltage maximum: 5.5V (vs. 6V for LP3990SD-1.5)
• Dropout voltage: 0.15V @ 150mA (vs. 0.2V)
• Quiescent current: 50 µA (vs. 80 µA)
• Package footprint: 6-WSON (2.2x2.5) (vs. 3x3)
• PSRR performance: 85dB ~ 40dB (100Hz ~ 100kHz) (vs. 55dB ~ 35dB at 1kHz ~ 10kHz)

The LP5900SD-1.5/NOPB requires PCB layout adjustment due to different package dimensions but provides superior electrical performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement: Select LP3990SD-1.5/NOPB when the obsolete LP3990SD-1.5 requires replacement. This part maintains identical electrical performance and package footprint, requiring no design modifications. The active product status ensures long-term availability, and ROHS3 compliance satisfies modern regulatory requirements.

For Design Optimization: Select LP5900SD-1.5/NOPB when PCB layout can accommodate the smaller 6-WSON (2.2x2.5) package footprint. This part delivers superior performance through reduced dropout voltage (0.15V vs. 0.2V), lower quiescent current (50 µA vs. 80 µA), and enhanced PSRR characteristics. The maximum input voltage of 5.5V remains suitable for most applications requiring 6V input tolerance; verify input voltage specifications for your specific circuit.

Both substitute parts carry ROHS3 compliance and REACH unaffected status, meeting current environmental and regulatory standards.

Frequently Asked Questions (FAQ)

Q: Can LP3990SD-1.5/NOPB replace LP3990SD-1.5 without PCB modifications?

A: Yes. LP3990SD-1.5/NOPB is pin-for-pin compatible with identical package dimensions (6-WSON 3x3), electrical specifications, and functional characteristics. No design changes are required.

Q: What are the key differences between LP3990SD-1.5/NOPB and LP5900SD-1.5/NOPB?

A: Both deliver 1.5V at 150mA with identical control and protection features. LP5900SD-1.5/NOPB offers lower dropout voltage (0.15V vs. 0.2V), reduced quiescent current (50 µA vs. 80 µA), and superior PSRR performance. However, it uses a smaller package footprint (6-WSON 2.2x2.5 vs. 3x3) and has a lower maximum input voltage (5.5V vs. 6V).

Q: Is LP5900SD-1.5/NOPB suitable if my circuit requires 6V input tolerance?

A: The LP5900SD-1.5/NOPB maximum input voltage is 5.5V. If your application requires operation at 6V input, verify that your actual input voltage remains at or below 5.5V. If higher input voltage tolerance is mandatory, use LP3990SD-1.5/NOPB.

Q: Do all three parts meet current compliance standards?

A: LP3990SD-1.5/NOPB and LP5900SD-1.5/NOPB are ROHS3 compliant and REACH unaffected. The original LP3990SD-1.5 is RoHS non-compliant. For new designs and procurement, use the compliant alternatives.

Q: What is the impact of package size difference when using LP5900SD-1.5/NOPB?

A: The LP5900SD-1.5/NOPB uses a smaller 6-WSON (2.2x2.5) package compared to the 6-WSON (3x3) of LP3990SD-1.5. PCB footprint and layout must be updated accordingly. Pin configuration remains identical, but physical placement and thermal considerations may differ.