LP38691SD-1.8 Linear Voltage Regulator — Equivalent & Substitute Parts

Part Overview

The LP38691SD-1.8 is a linear voltage regulator IC from Texas Instruments designed for positive fixed 1.8V output at 500mA in a 6-WSON (3x3) surface mount package. This part is classified as Obsolete, making identification of active equivalent alternatives essential for ongoing production and design continuity. The LP38691 series provides automotive-grade regulation with AEC-Q100 qualification, suitable for applications requiring stable 1.8V power delivery in constrained thermal environments.

Substiute Parts

LP38691SD-1.8

Texas InstrumentsIn Stock: 2935LP38691SD-1.8 Datasheet

Current PartRFQ

LP38691SD-1.8/NOPB

Texas InstrumentsIn Stock: 1676LP38691SD-1.8/NOPB Datasheet

DirectRFQ

LP38691QSD-1.8/NOPB

Texas InstrumentsIn Stock: 2201LP38691QSD-1.8/NOPB Datasheet

Parametric EquivalentRFQ

LP38691QSDX-1.8/NOPB

Texas InstrumentsIn Stock: 759LP38691QSDX-1.8/NOPB Datasheet

Parametric EquivalentRFQ

LP38691SDX-1.8/NOPB

Texas InstrumentsIn Stock: 4050LP38691SDX-1.8/NOPB Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LP38691SD-1.8 is determined by strict equivalence across the following critical parameters:

• Output voltage: 1.8V fixed
• Output current capability: 500mA
• Input voltage rating: 10V maximum
• Package type: 6-WDFN Exposed Pad (6-WSON 3x3)
• Quiescent current: 55 µA
• PSRR: 55dB (120Hz)
• Operating temperature range: -40°C to 125°C
• Automotive grade with AEC-Q100 qualification
• Over temperature protection

All substitute parts listed maintain identical electrical and mechanical specifications. Differences exist only in product status (Active vs. Obsolete), packaging format (Tape & Reel vs. bulk), and RoHS compliance status.

Parameter Comparison

Engineering Selection Recommendations

All four substitute parts are direct parametric equivalents to the LP38691SD-1.8 and are suitable for replacement in automotive applications requiring 1.8V/500mA regulation.

LP38691SD-1.8/NOPB is the primary direct substitute, maintaining identical electrical specifications while transitioning from Obsolete to Active product status and achieving ROHS3 compliance. The "/NOPB" designation indicates lead-free, halogen-free packaging.

LP38691QSD-1.8/NOPB and LP38691QSDX-1.8/NOPB are parametric equivalents with the "Q" suffix indicating qualification for extended temperature or enhanced screening. Both maintain full AEC-Q100 automotive qualification.

LP38691SDX-1.8/NOPB includes the "X" suffix, typically indicating extended operating range or enhanced reliability screening. This variant offers the highest available inventory (3950 Pcs) among active alternatives.

All substitute parts carry ROHS3 compliance, AEC-Q100 automotive qualification, and identical electrical performance specifications. Selection between variants should be based on inventory availability, specific application screening requirements, and supply chain considerations.

Frequently Asked Questions (FAQ)

Q: Can LP38691SD-1.8/NOPB directly replace the obsolete LP38691SD-1.8?

A: Yes. Both parts are electrically and mechanically identical. The primary differences are product status (Active vs. Obsolete) and RoHS compliance (ROHS3 vs. non-compliant). Pin configuration, package footprint, and electrical performance are identical.

Q: What does the "/NOPB" suffix indicate?

A: The "/NOPB" designation specifies lead-free, halogen-free (No Lead, No Bromine) packaging, meeting RoHS3 compliance requirements. This is a packaging and environmental designation, not an electrical specification change.

Q: Are the "Q" and "X" suffix variants electrically equivalent?

A: Yes. The "Q" and "X" suffixes indicate different screening or qualification levels applied by Texas Instruments but do not alter the core electrical specifications. All variants maintain 1.8V output, 500mA current capability, and identical PSRR, quiescent current, and temperature range.

Q: Can these parts be used interchangeably on the same PCB?

A: Yes. All substitute parts use the identical 6-WDFN Exposed Pad (6-WSON 3x3) package with the same pin configuration and footprint. No PCB redesign is required.

Q: Which substitute should be selected for new designs?

A: For new designs, select from the Active product status variants (LP38691SD-1.8/NOPB, LP38691QSD-1.8/NOPB, LP38691SDX-1.8/NOPB, or LP38691QSDX-1.8/NOPB). All meet current automotive and environmental standards. Selection should prioritize inventory availability and supply chain lead times.

Q: Are all substitutes AEC-Q100 qualified?

A: Yes. All listed substitute parts carry AEC-Q100 automotive qualification, maintaining the same reliability and screening standards as the original part.