LM3502SQ-25 - Dual-Output Boost LED Driver | Texas Instruments
MPN: LM3502SQ-25 ✓ ActiveLM3502SQ-25 Overview
A boost LED driver is a step-up DC-DC converter specialized for LED backlighting. It raises a battery or lower-voltage supply to the voltage required by a series LED string, while regulating the string current instead of relying on voltage alone. In the power hierarchy, the LM3502SQ-25 belongs to the LED-driver class of power-management semiconductors and uses pulse-width modulation for dimming and current regulation.
The verified device data identifies PWM step-up topology, two outputs, white-LED backlighting, and a 600 mA switch-current specification. Its switching frequency ranges from 800 kHz to 1.2 MHz, supporting compact magnetics and capacitor selection for display backlighting. Listed protections and control features include cycle-by-cycle current limit, over-voltage protection, under-voltage protection, and operation without external compensation.
The integrated cycle-by-cycle current limit helps control peak inductor current, while over-voltage and under-voltage protection address abnormal operating conditions. Because this is a boost converter, inductor current, diode or rectification behavior, capacitor ripple, and the LED-string forward voltage determine efficiency and thermal stress. The 4 mm by 4 mm WQFN format supports compact LCD backlighting boards, although the exposed-pad thermal path and inductor layout remain critical.
Typical uses include LCD monitor backlighting, dual-display illumination, notebook or portable-display lighting, instrument-panel lighting, and other white-LED strings requiring PWM dimming. Its two-output architecture is especially useful when both display strings need coordinated illumination, while a single large white-LED string can also be supported where the application permits.
Designers should follow the manufacturer datasheet for the exact pin assignments, LED current-setting method, compensation-free control behavior, and recommended external components. Keep the switching loop compact, connect the exposed pad to the required ground plane, provide low-loop-inductance current paths, and verify LED brightness, thermal rise, ripple, dimming range, and fault behavior across input-voltage and temperature limits. This page consolidates verified distributor specifications, datasheet links, application guidance, and explicit data gaps without inventing missing electrical values.
Drop-in alternatives for LM3502SQ-25 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
LM3502SQ-25/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM3502SQ-35
✅ Drop-In📋 Reference alternative (not in catalog)
LM3502SQ-25
✅ Drop-InContact for price
View Datasheet →LM3502SQ-25 Maximum Ratings & Electrical Characteristics
| Primary Function | Backlight white-LED driver |
| LED Type | White LED |
| Number of Outputs | 2 outputs |
| Converter Topology | PWM step-up boost |
| Dimming Method | PWM dimming |
| Switch Current | 600 mA |
| Switching Frequency | 800 kHz to 1.2 MHz |
| Package | 16-WQFN, 4 mm x 4 mm |
| Surface-Mount Construction | Surface-mount WQFN |
| Operating Temperature | -40 C to +125 C |
| External Compensation | Not required |
| Current-Limit Method | Cycle-by-cycle current limit |
| Overvoltage Protection | Provided |
| Undervoltage Protection | Provided |
| Target Applications | Dual-display and large single-string white-LED backlighting |
LM3502SQ-25 16-wqfn, 4 mm x 4 mm Pin Configuration Guide
Pin configuration for LM3502SQ-25 (16-wqfn, 4 mm x 4 mm package). This power device features gate, drain, and source terminals. For non-polarized packages, refer to the manufacturer datasheet for exact pin 1 orientation and footprint details. Common applications include power supply design, motor driving, and load switching.
No detailed pinout data available for LM3502SQ-25.
Refer to the datasheet for full pin configuration.
Typical Applications
LM3502SQ-25 is suitable for 6 applications: Dual-Display LCD Backlighting, Large Single White-LED String, Notebook and Portable Display Lighting, Instrument-Panel Illumination, Dual-Channel White-LED Backlight Control, Compact LED Lighting Power Boards.
Dual-Display LCD Backlighting
The LM3502SQ-25 fits dual-display backlighting because verified data identifies two outputs, PWM dimming, and a step-up boost topology for white-LED strings. Its 800 kHz to 1.2 MHz switching range supports compact display power-conversion layouts, while the 600 mA switch-current rating establishes the verified device rating around which the inductor and power path should be designed. PWM dimming allows brightness control when the panel and system timing require adjustable illumination. The compact 16-WQFN 4 mm by 4 mm package helps reduce board area, but exposed-pad thermal management, current-loop layout, and the LED strings’ forward-voltage requirements remain essential.
Recommended
Large Single White-LED String
The LM3502SQ-25 can serve a large single white-LED string when its two-output architecture can be allocated to the required lighting arrangement. Its boost topology raises the supply to the LED string voltage, while PWM operation controls illumination and the listed cycle-by-cycle current limit constrains peak switch current. The 600 mA switch-current rating and 800 kHz to 1.2 MHz frequency range provide concrete design starting points, but the actual LED current, inductor saturation current, diode rating, compensation-free control range, and thermal margin must be verified in the manufacturer datasheet.
Recommended
Notebook and Portable Display Lighting
The LM3502SQ-25 is applicable to portable-display backlighting where a boost converter is needed to drive white LEDs from a lower-voltage system rail. PWM dimming provides a direct brightness-adjustment mechanism, and the high switching-frequency range can help keep magnetic and capacitive component sizes compact. The device’s listed 600 mA switch current, two outputs, and 16-WQFN 4 mm by 4 mm package support space-constrained designs. Designers should still check battery or adapter input limits, LED-string voltage, light output at the required current, start-up behavior, and thermal performance across the -40 C to +125 C operating range stated in the available search data.
Recommended
Instrument-Panel Illumination
The LM3502SQ-25 can be considered for instrument-panel or control-panel white-LED illumination where multiple strings and adjustable brightness are useful. Its two-output structure allows two lighting channels, while PWM dimming supports coordinated brightness control. The 800 kHz to 1.2 MHz switching range and 16-WQFN footprint are useful for compact electronics, and the verified protection features include cycle-by-cycle current limit, over-voltage protection, and under-voltage protection. Final selection requires checking the panel’s forward voltage, current, expected flicker characteristics, heat rise, and whether the two channels need independent control.
Recommended
Dual-Channel White-LED Backlight Control
The LM3502SQ-25 is suited to a two-channel white-LED backlight arrangement because the verified specifications identify two outputs and PWM dimming. The boost converter raises the input rail as needed for the LED strings, while current regulation and PWM control determine illumination. At the stated 600 mA switch-current rating and 800 kHz to 1.2 MHz frequency range, component selection and PCB layout should be treated as a system task: inductor, rectifier, capacitors, LED current, and thermal paths all affect performance. The manufacturer datasheet must be used to confirm per-channel current settings, duty-cycle limits, fault behavior, and pin-level connections.
Recommended
Compact LED Lighting Power Boards
The LM3502SQ-25 is appropriate for compact LED-lighting power boards that require a boost stage and PWM brightness regulation without external compensation. Its 16-WQFN 4 mm by 4 mm package supports space-conscious assemblies, and the verified switching range of 800 kHz to 1.2 MHz permits a compact magnetics design once the output voltage and current are known. The listed protections help manage abnormal conditions, but designers should account for inductor saturation, switch and diode voltage stress, capacitor ripple, exposed-pad heat dissipation, and the conversion efficiency implied by the chosen LED-string operating point.
Recommended
Recommended Products Summary
Engineering reference data for LM3502SQ-25 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM3502SQ-25/NOPB | LM3502SQ-35 | LM3502SQ-25 |
|---|---|---|---|---|
| Package | 16-WQFN (4x4) | 16-WQFN (4x4) | 16-WQFN (4x4) | 16-WQFN (4x4) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
Key Differentiators
- Two-output architecture (vs LM3502SQ-35)
- Verified switching-current rating (vs LM3502SQ-25/NOPB)
- Compensation-free operation (vs LM3502SQ-35)
Design Notes
The verified 600 mA value is the switch-current rating, not a verified maximum LED-string current. Select the inductor, rectifier, capacitors, and PCB copper using the actual LED-string voltage, desired channel current, switching frequency, ripple target, and duty-cycle limits from the manufacturer datasheet. Confirm that every selected component tolerates the maximum boosted output plus switching overshoot, and check the regulator’s thermal rise at the highest specified input voltage.
Keep the boost converter’s high-current loop physically compact. Place input decoupling, switching components, the inductor, rectifier path, and output capacitor according to the manufacturer layout guidance so that switching-node copper is minimized and current returns to the device and exposed pad through a low-impedance path. The verified data confirms a 16-WQFN 4 mm by 4 mm package but does not provide a pin map or land pattern, so do not release a PCB from an inferred footprint.
Do not confuse the LM3502SQ-25 with an arbitrary LM3502 or LM3503 orderable code. The verified evidence confirms the target’s two-output, 600 mA, PWM step-up role and 16-WQFN package, but does not establish the electrical differences between LM3502SQ-35 or the LM3502SQ-25/NOPB ordering suffix. Before substitution, compare the manufacturer datasheets for pin function, input limits, LED current, PWM polarity, frequency, protection thresholds, and exposed-pad requirements.
Compliance Information
The provided search results do not state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. These fields remain unknown rather than inferred from the manufacturer name or package.
