LP3943ISQ LED Driver IC Equivalent & Substitute Parts

Part Overview

The LP3943ISQ is a 16-output LED driver IC manufactured by Texas Instruments, designed for power management applications including camera flash systems. This device features I2C/SMBus dimming control with 25mA per-channel output capability in a 24-WQFN surface mount package. The main part number is currently in Last Time Buy status with 26,300 units in stock. Alternative equivalent parts are available to ensure design continuity and supply chain flexibility.

Substiute Parts

LP3943ISQ

Texas InstrumentsIn Stock: 26346LP3943ISQ Datasheet

Current PartRFQ

LP3943ISQ/NOPB

Texas InstrumentsIn Stock: 45602LP3943ISQ/NOPB Datasheet

Parametric EquivalentRFQ

LP3943ISQX/NOPB

Texas InstrumentsIn Stock: 45688LP3943ISQX/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 of the LP3943ISQ is determined by the following critical parameters: number of outputs (16), current per channel (25mA), supply voltage range (2.3V–5.5V), package type (24-WQFN), dimming protocol (I2C/SMBus), and operating temperature range (-40°C to 85°C).

Parametric Equivalents (Same Electrical Specifications):

• LP3943ISQ/NOPB: Identical electrical specifications; differs only in packaging format (Cut Tape & Digi-Reel vs. Tape & Reel) and product status (Active vs. Last Time Buy)
• LP3943ISQX/NOPB: Identical electrical specifications; Tape & Reel packaging; Active product status

Reduced-Output Alternatives (8 Outputs):

• LP3944ISQ/NOPB: 8-output variant with identical per-channel current (25mA), supply voltage, dimming control, and package type; MSL rating differs (3 vs. 1)
• LP3944ISQX/NOPB: 8-output variant; Tape & Reel packaging; Active product status; MSL rating 3

Cross-Manufacturer Alternative (16 Outputs):

• PCA9552BS,118 (NXP USA Inc.): 16-output LED driver with matching output count, 25mA per-channel current, supply voltage range, and package footprint; manufactured by different supplier; MSL rating 1

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (16-Output Requirement): LP3943ISQ/NOPB and LP3943ISQX/NOPB are the preferred substitutes, offering identical electrical and thermal specifications with Active product status. Both maintain ROHS3 compliance and MSL rating 1. The choice between these two depends on packaging requirements: LP3943ISQ/NOPB is supplied in Cut Tape & Digi-Reel format, while LP3943ISQX/NOPB is supplied in Tape & Reel format.

For Reduced Output Designs (8-Output Requirement): LP3944ISQ/NOPB and LP3944ISQX/NOPB provide functional equivalence with half the output count. Both maintain identical per-channel current, supply voltage, and dimming protocol. MSL rating increases to 3 (168 hours), which may impact moisture-sensitive storage requirements. These parts are suitable only for applications requiring 8 or fewer LED driver outputs.

For Cross-Manufacturer Sourcing: PCA9552BS,118 from NXP USA Inc. matches the 16-output count, per-channel current, and supply voltage specifications. This part maintains MSL rating 1 and ROHS3 compliance. The package designation differs (24-HVQFN vs. 24-WQFN), requiring PCB layout verification for footprint compatibility despite identical pin count and spacing.

Frequently Asked Questions (FAQ)

Q: Can LP3943ISQ/NOPB be used as a direct replacement for LP3943ISQ? A: Yes. Both parts are electrically and thermally identical. The difference is packaging format (Cut Tape & Digi-Reel vs. Tape & Reel) and product status (Active vs. Last Time Buy). LP3943ISQ/NOPB is recommended for new designs due to Active status.

Q: What is the difference between LP3943ISQX/NOPB and LP3943ISQ/NOPB? A: Both are electrically identical 16-output LED drivers. LP3943ISQX/NOPB is supplied in Tape & Reel packaging, while LP3943ISQ/NOPB is supplied in Cut Tape & Digi-Reel format. Selection depends on assembly line requirements.

Q: Can LP3944ISQ/NOPB replace LP3943ISQ in all applications? A: No. LP3944ISQ/NOPB provides only 8 outputs compared to 16 outputs in LP3943ISQ. This part is suitable only for designs requiring 8 or fewer LED driver channels. MSL rating also increases from 1 to 3, affecting moisture-sensitive storage protocols.

Q: Is PCA9552BS,118 a suitable alternative to LP3943ISQ? A: PCA9552BS,118 matches the 16-output count, per-channel current (25mA), and supply voltage range (2.3V–5.5V). However, the package designation differs (24-HVQFN vs. 24-WQFN). PCB layout verification is required to confirm footprint compatibility, as pin spacing and exposed pad dimensions must be validated.

Q: What does MSL rating mean for these parts? A: Moisture Sensitivity Level (MSL) indicates the maximum time a component can be exposed to ambient conditions (typically 30°C, 85% relative humidity) before soldering. MSL 1 (Unlimited) allows indefinite storage without baking. MSL 3 (168 hours) requires baking before assembly if storage exceeds 168 hours. LP3943 variants have MSL 1; LP3944 variants have MSL 3.

Q: Are all substitute parts ROHS3 compliant? A: Yes. LP3943ISQ, LP3943ISQ/NOPB, LP3943ISQX/NOPB, LP3944ISQ/NOPB, LP3944ISQX/NOPB, and PCA9552BS,118 are all ROHS3 compliant and REACH unaffected.

Q: What is the difference between Tape & Reel and Cut Tape & Digi-Reel packaging? A: Tape & Reel packaging supplies components on continuous carrier tape suitable for automated pick-and-place assembly. Cut Tape & Digi-Reel packaging provides components on cut tape segments, typically for lower-volume or manual assembly operations. Both formats contain identical components; packaging format selection depends on assembly process requirements.