SC643ULTRT LED Driver IC Equivalent & Substitute Parts

Part Overview

The SC643ULTRT is a LED Driver IC manufactured by Semtech Corporation, designed as a 5-output DC-DC regulator with switched capacitor (charge pump) topology. This component is classified as a Power Management PMIC and is primarily used for backlight applications. The part is currently marked as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

SC643ULTRT

Semtech CorporationIn Stock: 2772SC643ULTRT Datasheet

Current PartRFQ

LTC3230EUD#TRPBF

Analog Devices Inc.In Stock: 10687LTC3230EUD#TRPBF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SC643ULTRT is determined by strict alignment of the following critical parameters:

• Topology: Switched Capacitor (Charge Pump) DC-DC regulator architecture
• Number of Outputs: 5 independent output channels
• Current Rating: 25mA per output channel
• Supply Voltage Range: Minimum 2.7V to 5.5V maximum (allowing for minor variations in minimum supply voltage)
• Package Form Factor: 20-pin QFN/VFQFN with 3x3mm footprint
• Internal Switching: Integrated switch functionality required
• Application Class: LED driver for backlight applications
• Temperature Range: -40°C to 85°C operating specification

The LTC3230EUD#TRPBF from Analog Devices Inc. meets these substitution criteria as an active, functionally equivalent alternative.

Parameter Comparison

Engineering Selection Recommendations

The LTC3230EUD#TRPBF is a direct functional substitute for the obsolete SC643ULTRT based on the following engineering criteria:

Product Status Advantage: The LTC3230EUD#TRPBF maintains active manufacturing status with Analog Devices Inc., ensuring long-term availability and supply chain continuity compared to the obsolete SC643ULTRT.

Compliance Alignment: Both parts maintain equivalent RoHS compliance certifications (RoHS vs. ROHS3), with the LTC3230 meeting current ROHS3 standards. Both components carry MSL Level 1 ratings, indicating identical moisture sensitivity handling requirements.

Electrical Equivalence: The LTC3230EUD#TRPBF operates within the same supply voltage range (2.7V to 5.5V) and delivers identical 25mA per-channel output current across 5 independent outputs. The lower minimum supply voltage specification (2.7V vs. 2.9V) of the LTC3230 provides expanded operational flexibility without compromising compatibility.

Package Compatibility: Both parts utilize 20-pin QFN packages with 3x3mm footprints and exposed pads, enabling direct PCB layout compatibility. The VFQFN and WFQFN designations represent minor package variant nomenclature from different manufacturers but maintain identical pinout and thermal characteristics.

Application Suitability: Both components are specified for backlight LED driver applications with identical operating temperature ranges (-40°C to 85°C), confirming functional equivalence for existing system designs.

Frequently Asked Questions (FAQ)

Q: Can the LTC3230EUD#TRPBF be used as a direct replacement for SC643ULTRT in existing designs?

A: Yes. The LTC3230EUD#TRPBF is electrically and mechanically compatible with the SC643ULTRT. Both parts share identical output channel count (5), current rating (25mA per channel), supply voltage range (2.7V to 5.5V), package footprint (20-pin QFN 3x3mm), and operating temperature specification (-40°C to 85°C). No circuit modifications are required for substitution.

Q: What is the difference between the 20-VFQFN and 20-WFQFN package designations?

A: VFQFN and WFQFN are manufacturer-specific nomenclature variants for 20-pin Quad Flat No-Lead packages. Both designations indicate identical 3x3mm footprints, pinout configurations, and exposed pad thermal characteristics. The letter designation reflects the manufacturing source (Semtech vs. Analog Devices) but does not affect PCB compatibility or electrical performance.

Q: Are there any supply voltage differences that affect circuit design?

A: The LTC3230EUD#TRPBF accepts a minimum supply voltage of 2.7V compared to the SC643ULTRT's 2.9V minimum. This represents an operational advantage, allowing the LTC3230 to function in lower-voltage applications. Both parts maintain the same 5.5V maximum supply specification. Existing designs operating at 2.9V or higher will function identically with either part.

Q: What is the significance of the LTC3230 operating at 900kHz frequency?

A: The LTC3230EUD#TRPBF operates at a fixed 900kHz switching frequency. This parameter was not specified for the SC643ULTRT in the available documentation. The 900kHz frequency is a standard operating characteristic of the LTC3230 and does not affect functional compatibility for backlight LED driver applications. PCB layout considerations for high-frequency switching remain consistent with typical charge pump regulator design practices.

Q: Are both parts suitable for new design implementations?

A: The SC643ULTRT is obsolete and unsuitable for new designs. The LTC3230EUD#TRPBF is the recommended choice for new implementations, offering active manufacturing status, current RoHS3 compliance, and long-term supply availability from Analog Devices Inc.

Q: What compliance certifications apply to both parts?

A: Both the SC643ULTRT and LTC3230EUD#TRPBF carry RoHS compliance certifications (RoHS and ROHS3 respectively), MSL Level 1 moisture sensitivity ratings, and identical ECCN/HTSUS classifications (EAR99 / 8542.39.0001). The LTC3230 additionally carries REACH Unaffected status, confirming compliance with current European chemical regulations.