LM3502SQ-16 Equivalent & Substitute Parts

Part Overview

The LM3502SQ-16 is an LED Driver IC with integrated DC-DC regulator functionality, designed for step-up (boost) conversion applications. This device features dual outputs, PWM dimming capability, and is optimized for backlight applications. The LM3502SQ-16 is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and production continuity.

Substiute Parts

LM3502SQ-16

Texas InstrumentsIn Stock: 1032LM3502SQ-16 Datasheet

Current PartRFQ

LT3486IFE#PBF

Analog Devices Inc.In Stock: 9416LT3486IFE#PBF Datasheet

MFR RecommendedRFQ

MP3312GC-Z

Monolithic Power Systems Inc.In Stock: 141095MP3312GC-Z Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the LM3502SQ-16 are selected based on the following critical parameters that define functional equivalence:

Primary Substitution Criteria:

• Device Type: DC DC Regulator with integrated LED Driver IC functionality
• Topology: Step-Up (Boost) conversion
• Number of Outputs: 2 outputs
• Dimming Control: PWM capability
• Internal Switch: Present
• Supply Voltage Compatibility: Minimum 2.5V input support
• Mounting Type: Surface Mount
• Applications: Backlight operation

Secondary Compatibility Factors:

• Output voltage capability (must support or exceed 16V)
• Switch current rating (minimum 400mA preferred)
• Package form factor (surface mount, pin-compatible or functionally equivalent)
• Operating temperature range (minimum -40°C to 85°C)
• Product status (active preferred for long-term availability)

The two identified substitute parts meet these core criteria while offering enhanced specifications in certain parameters, providing design flexibility for obsolete part replacement.

Parameter Comparison

Engineering Selection Recommendations

LT3486IFE#PBF (Analog Devices Inc.): This substitute offers the closest functional alignment to the LM3502SQ-16 in terms of core architecture. The device maintains dual-output configuration, PWM dimming, and step-up topology. The LT3486IFE#PBF provides enhanced specifications including higher maximum supply voltage (24V vs. 5.5V) and increased switch current capability (1.3A vs. 400mA). The device is currently in active production status with ROHS3 compliance, ensuring long-term availability and regulatory alignment. Package form factor differs (16-TSSOP vs. 16-WQFN), requiring PCB layout modification. Operating temperature range extends to 125°C, providing improved thermal margin.

MP3312GC-Z (Monolithic Power Systems Inc.): This substitute maintains supply voltage compatibility (2.7V to 5.5V) and dual-output configuration with step-up topology. The MP3312GC-Z offers dual dimming control (Analog and PWM), providing additional design flexibility. However, the switch current rating (30mA) is significantly lower than the LM3502SQ-16 (400mA), limiting applicability to lower-power backlight implementations. The device features a compact 9-WLCSP package, substantially smaller than the original 16-WQFN form factor. Active product status and ROHS3 compliance ensure regulatory and supply chain continuity. Output voltage capability (38V) exceeds the original specification.

Selection Basis:

• Both substitutes are active products with current manufacturing support
• Both maintain RoHS3 compliance, meeting modern regulatory requirements
• LT3486IFE#PBF is recommended for applications requiring current capacity preservation
• MP3312GC-Z is suitable for space-constrained designs with lower current requirements
• Package differences necessitate circuit board redesign in both cases

Frequently Asked Questions (FAQ)

Q: Can the LT3486IFE#PBF directly replace the LM3502SQ-16 without circuit modification?

A: Direct pin-for-pin replacement is not possible due to package differences (16-TSSOP vs. 16-WQFN). However, functional substitution is viable with PCB layout redesign. Pin configuration and functional signal mapping must be verified against respective datasheets prior to implementation.

Q: What is the primary limitation of the MP3312GC-Z as a substitute?

A: The switch current rating of 30mA is substantially lower than the LM3502SQ-16 specification of 400mA. This device is suitable only for low-power backlight applications. High-current LED driver applications require the LT3486IFE#PBF.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both LT3486IFE#PBF and MP3312GC-Z are ROHS3 compliant, meeting current regulatory requirements. The original LM3502SQ-16 is RoHS non-compliant, making substitution necessary for new designs subject to RoHS regulations.

Q: What is the impact of the extended operating temperature range in the substitute parts?

A: Both substitutes support -40°C to 125°C (junction temperature), compared to the original -40°C to 85°C (ambient temperature). This provides improved thermal margin and reliability in elevated-temperature environments.

Q: How do the switching frequencies compare, and does this affect circuit design?

A: The LM3502SQ-16 operates at 1MHz, while LT3486IFE#PBF operates at 2.2MHz and MP3312GC-Z at 1.2MHz. Higher switching frequency reduces output filter component size but may increase EMI considerations. Filter component values require recalculation based on the selected substitute's switching frequency.

Q: Can the MP3312GC-Z dual dimming capability (Analog and PWM) replace PWM-only dimming?

A: Yes. The MP3312GC-Z supports PWM dimming as specified in the original device. The additional analog dimming capability provides design flexibility without compromising PWM functionality.

Q: What supply voltage range compatibility exists across all three devices?

A: The common supply voltage range across all devices is 2.5V to 5.5V. The LT3486IFE#PBF extends the maximum to 24V, enabling broader input voltage applications.