LM3502ITL-35/NOPB LED Driver IC Equivalent & Substitute Parts

Part Overview

The LM3502ITL-35/NOPB is a LED Driver IC manufactured by Texas Instruments, classified as a Power Management (PMIC) component. This device functions as a 2-output DC-DC regulator with step-up (boost) topology, PWM dimming capability, and a 750mA switch current rating. The part is designated as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity.

Substiute Parts

LM3502ITL-35/NOPB

Texas InstrumentsIn Stock: 1191LM3502ITL-35/NOPB Datasheet

Current PartRFQ

A8518KLPTR-T

Allegro MicroSystemsIn Stock: 18832A8518KLPTR-T Datasheet

MFR RecommendedRFQ

ISL97682IRTZ-T

Renesas Electronics CorporationIn Stock: 1145ISL97682IRTZ-T Datasheet

MFR RecommendedRFQ

LT3466EDD#PBF

Analog Devices Inc.In Stock: 3046LT3466EDD#PBF Datasheet

MFR RecommendedRFQ

LT3466EFE#PBF

Analog Devices Inc.In Stock: 1385LT3466EFE#PBF Datasheet

MFR RecommendedRFQ

LT3486EDHC#PBF

Analog Devices Inc.In Stock: 3125LT3486EDHC#PBF Datasheet

MFR RecommendedRFQ

LT3497EDDB#TRMPBF

Analog Devices Inc.In Stock: 8086LT3497EDDB#TRMPBF Datasheet

MFR RecommendedRFQ

LT3909EMSE#PBF

Analog Devices Inc.In Stock: 1020LT3909EMSE#PBF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM3502ITL-35/NOPB is determined by the following critical parameters:

• Topology: Step-up (boost) DC-DC regulator with internal switch
• Number of Outputs: 2 outputs
• Voltage Supply Range: Minimum 2.5V input capability; maximum supply voltage ≥5.5V
• Output Voltage: 35V nominal output
• Current Capability: Switch current ≥750mA per channel
• Dimming Control: PWM dimming support
• Application: LED backlight driver
• Compliance: ROHS3 compliant

Substitute parts must satisfy the core functional requirements: dual-output boost topology with PWM dimming, input voltage compatibility with 2.5V–5.5V range, output voltage capability at or above 35V, and switch current capacity meeting or exceeding 750mA. Parts are grouped by their ability to meet these electrical and mechanical constraints.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility)

LT3497EDDB#TRMPBF and LT3466EDD#PBF are the most direct substitutes for the LM3502ITL-35/NOPB. Both are manufactured by Analog Devices Inc., maintain active product status, support dual-output boost topology with PWM dimming, and operate within compatible voltage ranges. LT3497EDDB#TRMPBF matches the 35V output specification exactly and supports 400mA switch current. LT3466EDD#PBF provides 39.5V output capability with 400mA current rating and operates at 1MHz switching frequency, identical to the original part. Both components are ROHS3 compliant with MSL 1 rating.

Secondary Substitutes (Functional Equivalence with Trade-offs)

ISL97682IRTZ-T (Renesas Electronics) and A8518KLPTR-T (Allegro MicroSystems) provide functional boost topology with dual outputs and PWM dimming. ISL97682IRTZ-T delivers 45V output at 100mA per channel, suitable for applications where higher output voltage is acceptable but lower current capacity is a constraint. A8518KLPTR-T supports 40V output with 200mA per channel and includes automotive-grade qualification (AEC-Q100) with extended operating temperature to 125°C, beneficial for automotive backlight applications.

Limited Substitutes (Reduced Current Capacity)

LT3909EMSE#PBF (Analog Devices Inc.) operates as a dual-output boost regulator with 40V output capability and supports both analog and PWM dimming. However, the 50mA per-channel current rating is significantly below the 750mA requirement of the original part, limiting its use to low-power LED applications only.

Compliance and Certification

All substitute parts maintain ROHS3 compliance. A8518KLPTR-T carries AEC-Q100 automotive qualification, appropriate for automotive-grade backlight applications. Moisture sensitivity levels range from MSL 1 (unlimited) to MSL 3 (168 hours), with MSL 1 parts (LT3497EDDB#TRMPBF, LT3466EDD#PBF, LT3909EMSE#PBF) offering superior shelf-life stability.

Frequently Asked Questions (FAQ)

Q: Can LT3497EDDB#TRMPBF directly replace LM3502ITL-35/NOPB?

A: LT3497EDDB#TRMPBF is a direct functional equivalent. Both are dual-output boost regulators with 35V output, PWM dimming, and 400mA switch current capability. The primary difference is package type: LM3502ITL-35/NOPB uses 10-TµSMD (1.9x2.07), while LT3497EDDB#TRMPBF uses 10-DFN (3x2). PCB layout modifications are required to accommodate the different package footprint.

Q: What is the significance of the 750mA switch current specification?

A: The 750mA switch current rating defines the maximum internal switch current capacity of the regulator. This parameter determines the maximum power delivery capability. Substitute parts with lower switch current ratings (such as ISL97682IRTZ-T at 100mA or LT3909EMSE#PBF at 50mA) cannot deliver equivalent power levels and are suitable only for reduced-power applications.

Q: Why is LT3909EMSE#PBF listed as a substitute if its current rating is only 50mA?

A: LT3909EMSE#PBF is included because it maintains the core functional topology (dual-output boost regulator with PWM dimming) and was identified in the original part's substitute list. However, its 50mA per-channel current is insufficient for applications requiring the full 750mA capability of the LM3502ITL-35/NOPB. Selection of this part is appropriate only for low-power LED backlight designs.

Q: What are the package considerations when substituting these parts?

A: Package type changes require PCB redesign. LM3502ITL-35/NOPB uses 10-TµSMD (1.9x2.07), while substitutes use various packages: LT3497EDDB#TRMPBF and LT3466EDD#PBF use 10-DFN (3x3 or 3x2), ISL97682IRTZ-T uses 16-TQFN (3x3), A8518KLPTR-T uses 16-eTSSOP-EP, and LT3909EMSE#PBF uses 12-MSOP-EP. Footprint, thermal pad design, and trace routing must be updated accordingly.

Q: Is A8518KLPTR-T suitable for automotive applications?

A: Yes. A8518KLPTR-T carries AEC-Q100 automotive qualification and operates across -40°C to 125°C, exceeding the -40°C to 85°C range of the original part. This makes it appropriate for automotive backlight driver applications. However, its 200mA per-channel current is lower than the 750mA specification of LM3502ITL-35/NOPB.

Q: What is the difference between PWM-only and Analog+PWM dimming?

A: PWM-only dimming (LM3502ITL-35/NOPB, ISL97682IRTZ-T, LT3497EDDB#TRMPBF, LT3466EDD#PBF) controls LED brightness through pulse-width modulation of the switching signal. Analog+PWM dimming (LT3909EMSE#PBF, A8518KLPTR-T) supports both analog voltage control and PWM modulation, offering additional flexibility in dimming implementation. Selection depends on the specific dimming control architecture of the target application.

Q: How does switching frequency affect substitution compatibility?

A: Switching frequency (ranging from 600kHz to 2.3MHz across substitutes) affects output ripple, component size, and EMI characteristics. The original LM3502ITL-35/NOPB operates at 1MHz. Substitutes with different frequencies may require adjustment of external filter components and PCB layout to maintain equivalent noise performance. Higher frequencies (2MHz–2.3MHz) typically reduce component size but may increase switching losses.

Q: What is the importance of Moisture Sensitivity Level (MSL)?

A: MSL rating defines the maximum time a component can be stored in ambient conditions before soldering. MSL 1 (unlimited) parts have no time restriction. MSL 2 (1 year) and MSL 3 (168 hours) parts require controlled storage and faster assembly after opening. For supply chain flexibility, MSL 1 parts (LT3497EDDB#TRMPBF, LT3466EDD#PBF, LT3909EMSE#PBF) are preferred.