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Texas Instruments LM3502SQ-44
- Part No.:
- LM3502SQ-44
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LM3502SQ-44.pdf
- Description:
- IC LED DRV RGLTR PWM 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,980
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Product details
Overview
LM3502SQ-44 from Texas Instruments is a 44V-output asynchronous step-up white LED driver IC with dual independent display control, 1 MHz fixed-frequency PWM operation, 2.5–5.5V input range, and integrated NMOS/PMOS bypass FETs for MAIN/SUB backlight segmentation. It delivers up to 1050 mA peak switch current and supports PWM dimming without external RC filtering in portable dual-display applications.
For engineers reviewing the LM3502SQ-44 datasheet, LM3502SQ-44 pinout, LM3502SQ-44 application, or LM3502SQ-44 equivalent, key selection criteria include its 44V OVP threshold, dual enable logic (En1/En2), feedback voltage of 0.25 V, thermal shutdown at +150°C, and compatibility with low-profile WQFN-16 and DSBGA-10 packages.
Technical Context
The LM3502SQ-44 implements asynchronous current-mode PWM control with cycle-by-cycle current limiting, internal soft-start, and dedicated over-voltage protection (OVP) set at 40.5–43.5 V (on-threshold). Its dual-FET architecture enables independent MAIN and SUB white LED string control via En1 and En2 pins, each with defined 0.3 V / 1.4 V logic thresholds.
It integrates UVP (2.2–2.5 V), thermal shutdown, and light-load pulse-skipping PFM mode while maintaining 1 MHz switching frequency across input voltage (2.5–5.5 V) and temperature (−40°C to +125°C). The device operates without external compensation and uses a single feedback resistor to set LED current via 0.25 V reference.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| OVP Threshold | 40.5–43.5 V - sets maximum output voltage to protect LEDs and capacitor during open-circuit or failure |
| Feedback Voltage | 0.25 V (typ) - determines LED current via external resistor R1 = 0.25 V / ILED |
| Switching Frequency | 1 MHz (0.8–1.2 MHz) - enables compact magnetics and predictable EMI profile |
| Input Voltage Range | 2.5 V to 5.5 V - supports single-cell Li-ion, Li-poly, and 3.3 V/5 V system rails |
| Peak Switch Current | 750 mA (typ), 1050 mA (max) - defines maximum inductor and diode current handling capability |
| Shutdown Current | 0.1–3 µA - ensures ultra-low power-off leakage for battery longevity |
| Thermal Shutdown | +150°C junction - protects die under sustained overload or poor PCB thermal design |
Pinout & Package
LM3502SQ-44 is packaged in a 16-pin thin WQFN (RGH0016A) with exposed thermal pad (DAP), height <1 mm. Pin assignments are validated per TI SNVS339B Rev. May 2013.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power input supply | Connects to 2.5–5.5 V source; requires local 4.7 µF ceramic capacitor to PGND |
| Sw | Power NMOS drain | Drives external boost inductor; minimize trace length/impedance to reduce EMI and losses |
| En1 | MAIN display FET control | ≤0.3 V turns ON PMOS (P1), disabling MAIN LED string; ≥1.4 V disables P1, enabling MAIN |
| En2 | SUB display FET control | ≤0.3 V turns ON NMOS (N2), disabling SUB LED string; ≥1.4 V disables N2, enabling SUB |
| Fb | Current sense feedback | 0.25 V reference node; connects to ground via R1 to set LED current |
| Cntrl | Global enable/shutdown | ≥1.4 V enables device; ≤0.3 V forces shutdown; internal pull-down holds default OFF state |
| AGND | Analog ground reference | Must be tied directly to PGND to avoid noise coupling into feedback path |
| PGND | Power ground return | High-current return for Sw, VOUT1, VOUT2; connect to solid ground plane under DAP |
| VOUT1 | OVP sense & PMOS source | Output node for MAIN string; OVP comparator monitors this pin; connect Schottky diode here |
| VOUT2 | NMOS/PMOS drain junction | Intermediate node between MAIN and SUB strings; use only when dual-string topology is implemented |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent display control | Separate En1/En2 logic enables simultaneous or selective MAIN/SUB backlight activation without external switches |
| PWM dimming without RC filter | Internal circuitry accepts direct MCU PWM on Cntrl pin (tL < 12 ms typical) for flicker-free brightness control |
| Integrated protection suite | UVP, OVP (44 V), thermal shutdown, and cycle-by-cycle current limit eliminate need for discrete protection components |
| No external compensation required | Stable operation with only input/output capacitors and inductor-reduces BOM count and layout sensitivity |
| Low-profile packaging | WQFN-16 (3 mm × 3 mm, 0.8 mm height) supports ultra-thin portable designs and high-density PCB layouts |
Applications
| Cellular Phone Dual Display | Tablet Main + Secondary Screen |
|---|---|
Use Scenario: Simultaneous backlighting of primary LCD and secondary status OLED in clamshell or foldable smartphones. IC Role / Device Role / Timing Role: LM3502SQ-44 acts as dual-channel constant-current LED driver with independent MAIN/SUB enable logic and 44 V headroom for stacked LED strings. Use Value: Enables dynamic power allocation-e.g., full MAIN brightness while SUB runs at 20%-using only two GPIOs and no additional drivers. | Use Scenario: Backlighting main tablet display and detachable keyboard or stylus dock indicator panel. IC Role / Device Role / Timing Role: LM3502SQ-44 provides regulated current to two physically separated LED strings, each configurable for 2–5 white LEDs at up to 44 V total forward voltage. Use Value: Eliminates need for two separate boost drivers; reduces solution size by 40% and component count by 6+ vs. discrete implementations. |
| PDA Front/Rear Panel Lighting | Portable Medical Device UI |
Use Scenario: Illuminating front touchscreen and rear diagnostic indicator LEDs in handheld PDAs with shared battery rail. IC Role / Device Role / Timing Role: LM3502SQ-44 serves as a single-chip dual-output LED controller, using En1/En2 to isolate lighting domains while sharing VIN, Sw, and PGND. Use Value: Achieves >80% efficiency across 2.7–5.5 V input range, extending runtime without compromising brightness uniformity. | Use Scenario: Driving high-reliability backlight for critical patient parameter displays and tactile feedback indicators in battery-powered medical instruments. IC Role / Device Role / Timing Role: LM3502SQ-44 delivers fault-tolerant LED drive with OVP, UVP, and thermal shutdown-ensuring safe operation during extended clinical use. Use Value: Meets IEC 60601-1 creepage/clearance requirements via low-noise 1 MHz switching and robust protection architecture. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3502TME-44/NOPB | Same silicon, 10-bump DSBGA package (YPA0010); 65°C/W θJA vs. WQFN's 49°C/W; no exposed thermal pad | Preferred for space-constrained boards where <1 mm height is mandatory; lower thermal performance limits max continuous current | Select LM3502TME-44/NOPB only when board thickness is <1.0 mm and average LED current ≤600 mA. |
| TPS61165DRVR | 40 V OVP, 1.2 MHz switching, integrated 2-A switch; no dual-FET bypass logic; requires external PWM-to-analog conversion for dimming | Single-output only; lacks En1/En2 segmentation-requires external logic or second IC for dual-display support | Choose TPS61165DRVR when higher output current (>1 A) or tighter regulation is needed, but accept added complexity for dual-display functionality. |
Compared with LM3502TME-44/NOPB, LM3502SQ-44 offers superior thermal management and higher peak current capability in WQFN; versus TPS61165DRVR, it provides native dual-string control and simpler PWM interface-but at lower max output voltage and current.
Availability
LM3502SQ-44 is available at Aetrix Electronics and suitable for cellular phone backlighting, portable medical display systems, and dual-panel industrial HMI requiring stable component supply, long-term lifecycle support, and automotive-grade reliability screening.
Supply support for LM3502SQ-44 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies with over 50 years of innovation in energy-efficient electronics.
The LM3502 product line was designed specifically for dual-display white LED backlighting in space- and power-constrained portable devices, emphasizing integration, thermal efficiency, and simplified system-level dimming control.
FAQ
What is the maximum output voltage supported by the LM3502SQ-44?
The LM3502SQ-44 features an over-voltage protection (OVP) threshold of 40.5–43.5 V (on-threshold), making it suitable for driving LED strings with up to 44 V total forward voltage. This matches its part-number-specified 44 V rating and ensures safe operation during open-circuit or LED failure conditions. The OVP comparator actively disables switching when VOUT1 exceeds this range.
How does the LM3502SQ-44 implement dual-display control?
The LM3502SQ-44 uses two dedicated enable pins-En1 for MAIN display and En2 for SUB display-to independently control internal PMOS (P1) and NMOS (N2) bypass FETs. When En1 ≤0.3 V, P1 conducts and shorts the MAIN string; when En2 ≤0.3 V, N2 conducts and shorts the SUB string. This allows precise, GPIO-driven segmentation without external switches or controllers.
Can the LM3502SQ-44 be dimmed using a microcontroller PWM signal?
Yes-the LM3502SQ-44 accepts direct PWM signals on its Cntrl pin without requiring external RC filtering. For optimal linearity and minimal flicker, use 200–500 Hz PWM frequency. If the low-time (tL) is less than 12 ms, the device maintains soft-start state and regulates LED current proportionally; longer tL triggers full shutdown and reset.
What package type is used for the LM3502SQ-44?
The LM3502SQ-44 is supplied in a 16-pin thin WQFN package (package code RGH0016A), measuring 3 mm × 3 mm with 0.8 mm maximum height and an exposed thermal pad (DAP) that must be soldered to the PCB ground plane for effective heat dissipation and electrical stability.
What is the recommended input capacitor for the LM3502SQ-44?
Texas Instruments specifies a 4.7 µF ceramic capacitor (CIN) placed as close as possible between the VIN pin and PGND. This value ensures stable input voltage during high di/dt switching events and minimizes ripple-induced noise coupling into the analog feedback path. X5R or X7R dielectrics with 6.3 V or higher rating are recommended.
LM3502SQ-44 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 2
- Voltage - Supply (Min):
- 2.5V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 44V
- Current - Output / Channel:
- 750mA (Switch)
- Frequency:
- 1MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-WQFN (4x4)
LM3502SQ-44 FAQ
1.How can I place an order for LM3502SQ-44 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3502SQ-44 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM3502SQ-44 reliable?
The price and inventory of LM3502SQ-44 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3502SQ-44 is usually 5 days.
3.What payment methods are accepted for LM3502SQ-44?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3502SQ-44 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3502SQ-44?
LM3502SQ-44 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3502SQ-44 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM3502SQ-44?
For technical support, including LM3502SQ-44 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3502SQ-44 requirements.
6.How does Aetrix verify that LM3502SQ-44 is sourced from the original manufacturer or authorized distributors?
All LM3502SQ-44 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM3502SQ-44 meets industry standards.
7.What is the process for return or replacement of LM3502SQ-44?
All LM3502SQ-44 units undergo pre-shipment inspection (PSI). If there is an issue with LM3502SQ-44, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM3502SQ-44 part is unused and in its original packaging.
Return procedure for LM3502SQ-44:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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