LP3943ISQX LED Driver IC Equivalent & Substitute Parts

Part Overview

The LP3943ISQX is a 16-output LED driver IC manufactured by Texas Instruments, designed for power switch applications with I2C/SMBus dimming control. This part is classified as obsolete, which necessitates identification of active equivalent alternatives for new designs and ongoing production requirements. The LP3943ISQX operates across a 2.3V to 5.5V supply range with 25mA per-channel output capability in a 24-WQFN surface mount package, making it suitable for camera flash and similar LED control applications.

Substiute Parts

LP3943ISQX

Texas InstrumentsIn Stock: 3631LP3943ISQX Datasheet

Current PartRFQ

LP3943ISQX/NOPB

Texas InstrumentsIn Stock: 45688LP3943ISQX/NOPB Datasheet

DirectRFQ

LP3943ISQ/NOPB

Texas InstrumentsIn Stock: 45602LP3943ISQ/NOPB Datasheet

Parametric EquivalentRFQ

LP3944ISQ/NOPB

Texas InstrumentsIn Stock: 25301LP3944ISQ/NOPB Datasheet

Parametric EquivalentRFQ

LP3944ISQX/NOPB

Texas InstrumentsIn Stock: 1814LP3944ISQX/NOPB Datasheet

Parametric EquivalentRFQ

PCA9552BS,118

NXP USA Inc.In Stock: 3386PCA9552BS,118 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LP3943ISQX is determined by the following critical parameters:

• Number of Outputs: 16 outputs (primary functional requirement)
• Supply Voltage Range: 2.3V to 5.5V (must match or encompass)
• Output Current per Channel: 25mA (must match)
• Package Type: 24-WQFN (4x4) Exposed Pad (physical compatibility)
• Operating Temperature Range: -40°C to 85°C (environmental specification)
• Dimming Control Interface: I2C/SMBus (control protocol compatibility)

Substitutes are categorized into two groups:

Group 1 - Direct Functional Equivalents (16 Outputs): Parts maintaining identical output count and all electrical specifications. These provide pin-for-pin compatibility and are suitable for direct replacement.

Group 2 - Parametric Equivalents (8 Outputs): Parts with reduced output count but identical electrical characteristics. These require circuit redesign and are applicable only when output reduction is acceptable.

Group 3 - Cross-Manufacturer Equivalent (16 Outputs): NXP alternative with matching output count and electrical specifications but different manufacturer origin.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation - LP3943ISQX/NOPB: This part is the direct successor to the obsolete LP3943ISQX, maintaining identical electrical specifications, output count, and package geometry. It is ROHS3 compliant and available in Tape & Reel packaging suitable for production environments. This is the preferred choice for new designs and production transitions.

Secondary Recommendation - LP3943ISQ/NOPB: Functionally equivalent to LP3943ISQX/NOPB with identical electrical and output specifications. Available in Cut Tape and Digi-Reel formats, suitable for lower-volume applications or prototype development. ROHS3 compliant with MSL 1 rating.

Alternative for Reduced Output Requirements - LP3944ISQ/NOPB or LP3944ISQX/NOPB: These parts reduce output count to 8 channels while maintaining all other electrical parameters. Selection requires circuit redesign to accommodate half the output channels. Both are ROHS3 compliant and active products. LP3944ISQX/NOPB carries MSL 3 rating (168 hours), requiring controlled storage conditions.

Cross-Manufacturer Option - PCA9552BS,118: NXP alternative maintaining 16-output configuration and all critical electrical specifications. Physically compatible with 24-HVQFN package (similar to WQFN). ROHS3 compliant with MSL 1 rating. Suitable when Texas Instruments parts are unavailable or when multi-source qualification is required.

Frequently Asked Questions (FAQ)

Q: Can LP3943ISQ/NOPB directly replace LP3943ISQX in production?

A: Yes. Both parts maintain identical electrical specifications, output count (16), supply voltage range (2.3V to 5.5V), per-channel current (25mA), and package type (24-WQFN 4x4). The primary difference is packaging format (Cut Tape vs. bulk). Both are ROHS3 compliant and active products.

Q: What is the difference between LP3943ISQX/NOPB and LP3944ISQX/NOPB?

A: The LP3944 series provides 8 outputs instead of 16. All other electrical parameters remain identical. Selection of LP3944 requires circuit redesign to function with half the available output channels. The LP3944ISQX/NOPB carries MSL 3 rating versus MSL 1 for LP3943 variants.

Q: Is PCA9552BS,118 a suitable replacement for LP3943ISQX?

A: PCA9552BS,118 maintains 16 outputs and all critical electrical specifications (2.3V to 5.5V supply, 25mA per channel, -40°C to 85°C operation). The package is 24-HVQFN instead of 24-WQFN, requiring verification of PCB footprint compatibility. This part is suitable when cross-manufacturer sourcing is acceptable.

Q: Why is the original LP3943ISQX marked as obsolete?

A: The LP3943ISQX is obsolete due to product lifecycle management by Texas Instruments. Active equivalents (LP3943ISQX/NOPB and LP3943ISQ/NOPB) are available with improved compliance status (ROHS3) and continued manufacturing support.

Q: What are the packaging implications for production?

A: LP3943ISQX/NOPB is supplied in Tape & Reel format, standard for automated assembly. LP3943ISQ/NOPB is available in Cut Tape and Digi-Reel formats, suitable for lower-volume or prototype applications. PCA9552BS,118 is supplied in Cut Tape format. Verify packaging compatibility with your assembly process requirements.

Q: Are there any compliance differences between substitute options?

A: All active substitutes (LP3943ISQX/NOPB, LP3943ISQ/NOPB, LP3944 variants, and PCA9552BS,118) are ROHS3 compliant. The original LP3943ISQX is non-compliant. Moisture sensitivity levels vary: LP3943 variants carry MSL 1 (unlimited), while LP3944 variants carry MSL 3 (168 hours), requiring controlled storage.