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Texas Instruments LM3502SQX-16/NOPB
- Part No.:
- LM3502SQX-16/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LM3502SQX-16/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,553
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Product details
Overview
LM3502SQX-16/NOPB from Texas Instruments is a 16-V output, asynchronous current-mode step-up DC/DC converter optimized for dual white LED backlighting in portable displays. It integrates dual internal FET switches (PMOS and NMOS) for independent MAIN/SUB display control, operates from 2.5 V to 5.5 V input, delivers >80% efficiency at 1 MHz fixed switching frequency, and supports PWM dimming without external RC filtering - used in cellular phones and PDAs with 2–5 LEDs per string.
For engineers reviewing the LM3502SQX-16/NOPB datasheet, LM3502SQX-16/NOPB pinout, LM3502SQX-16/NOPB application, or LM3502SQX-16/NOPB equivalent, key selection criteria include its 16 V OVP threshold, dual enable logic (En1/En2), feedback voltage of 0.25 V, thermal shutdown protection, and WQFN-16 package compatibility with high-density PCB layouts.
Technical Context
The LM3502SQX-16/NOPB implements asynchronous current-mode PWM control with cycle-by-cycle current limiting and dedicated over-voltage protection (OVP) set at 14.0–16.5 V. Its internal architecture includes separate PMOS (P1) and NMOS (N2) bypass FETs controlled by En1 and En2 pins, enabling independent MAIN and SUB display string activation.
It features integrated soft-start, under-voltage lockout (UVP at 2.2–2.5 V), and light-load pulse-frequency modulation (PFM) mode. The device uses a single feedback pin (Fb) referenced to 0.25 V to set LED current via external resistor R1, eliminating need for external compensation networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| OVP Threshold | 14.0–16.5 V - sets maximum regulated output voltage to protect LEDs and external diode/capacitor |
| Feedback Voltage | 0.18–0.30 V (typ 0.25 V) - determines LED current via R1 = VFb / ILED; enables precise current setting |
| Switching Frequency | 0.8–1.2 MHz (typ 1 MHz) - allows use of small inductors (e.g., 22 µH) and reduces EMI filtering burden |
| Input Voltage Range | 2.5 V to 5.5 V - compatible with single-cell Li-ion (3.0–4.2 V) and dual-cell alkaline (2.4–3.2 V) supplies |
| Efficiency | >80% - measured at typical operating points (e.g., VIN = 3.3 V, 10 mA LED current), minimizing thermal load |
| Shutdown Current | 0.1–3 µA - ensures ultra-low power-off state for battery longevity in portable devices |
| Junction Temp Range | −40°C to +125°C - supports operation in extended industrial and mobile environments |
Pinout & Package
LM3502SQX-16/NOPB is housed in a 16-pin, 3 mm × 3 mm, 0.8 mm max height thermally enhanced WQFN package (TI package code RGH0016A) with exposed die attach pad (DAP) soldered to PCB ground plane for optimal thermal dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Supply input | Connects to 2.5–5.5 V source; requires local 4.7 µF ceramic capacitor to PGND |
| Sw | Power switch drain | Drain of internal NMOS (N1); connects to inductor and Schottky diode anode |
| En1 | MAIN display FET control | Controls PMOS (P1) switch; ≤0.3 V enables MAIN OFF, ≥1.4 V enables MAIN ON |
| En2 | SUB display FET control | Controls NMOS (N2) switch; ≤0.3 V enables SUB OFF, ≥1.4 V enables SUB ON |
| Fb | Current sense feedback | 0.25 V reference node; sets LED current via resistor to AGND |
| Cntrl | Global enable/shutdown | ≥1.4 V enables device; ≤0.3 V forces shutdown; supports PWM dimming directly |
| AGND | Analog ground | Reference for Fb, En1, En2, Cntrl; must tie directly to PGND near device |
| PGND | Power ground | High-current return path for Sw, VOUT1, VOUT2; connects to DAP and PCB ground plane |
| VOUT1 | Main output/OVP sense | Source of P1 and OVP sensing node; connects to cathode of Schottky diode and output cap |
| VOUT2 | Sub-string output | Drain of P1 and N2; used for second LED string when dual-display configuration is active |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent display control | Separate En1/En2 logic enables MAIN/SUB LED strings without external MOSFETs or routing complexity |
| PWM dimming without RC filter | Internal circuitry accepts direct MCU PWM signal on Cntrl pin (200–500 Hz optimal) - eliminates BOM cost and layout area |
| Integrated protection suite | UVP, OVP, thermal shutdown, and cycle-by-cycle current limit prevent damage during fault conditions |
| No external compensation required | Stable operation with only input/output capacitors and inductor - simplifies design validation and reduces debug time |
| Low-profile WQFN package | 3 mm × 3 mm × 0.8 mm footprint supports thin portable form factors and improves thermal performance via DAP |
Applications
| Cellular Phone Backlight | PDA Dual-Display System |
|---|---|
Use Scenario: Single Li-ion powered handset with main LCD and secondary status OLED display. IC Role / Device Role / Timing Role: Step-up controller providing regulated 16 V to two independent white LED strings (MAIN: 4 LEDs, SUB: 3 LEDs). Use Value: Enables simultaneous brightness control of both displays using En1/En2 logic and global PWM dimming on Cntrl pin - no additional driver ICs needed. | Use Scenario: Handheld PDA with primary touchscreen and secondary monochrome status panel. IC Role / Device Role / Timing Role: Dual-output LED driver delivering 16 V to MAIN (5 LEDs) and SUB (2 LEDs) strings with independent on/off sequencing. Use Value: Reduces component count by integrating dual FET switches and OVP - eliminates discrete PMOS/NMOS and external protection diodes. |
| Portable Media Player UI | Industrial Handheld Terminal |
Use Scenario: Battery-powered media player with front-panel button backlight and rear LCD backlight. IC Role / Device Role / Timing Role: White LED driver managing two distinct lighting zones using shared inductor and single feedback loop. Use Value: Achieves >80% efficiency across 2.7–4.2 V input range - extends playback time while maintaining consistent luminance. | Use Scenario: Ruggedized handheld terminal operating in −20°C to +70°C ambient with dual display requirement. IC Role / Device Role / Timing Role: Robust LED driver supporting extended temperature range (−40°C to +125°C TJ) and ESD-hardened I/O (2 kV HBM). Use Value: Ensures reliable backlight operation under thermal stress and electrostatic events - no derating required up to 125°C junction. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3502SQX-25/NOPB | Higher OVP threshold (21.5–25.5 V); same pinout, package, and control logic | Supports longer LED strings (up to 8 LEDs @ 3.2 V each); not suitable for 16 V–limited designs | Select only if system requires >16 V output; verify inductor/diode voltage ratings |
| TPS61160DRVR | Single-output, 28-V OVP; no dual-FET bypass; requires external PWM-to-analog conversion for dimming | Lacks independent MAIN/SUB control; suited for single-string applications only | Choose when dual-display functionality is unnecessary and board space permits external RC network |
Compared with LM3502SQX-25/NOPB and TPS61160DRVR, the LM3502SQX-16/NOPB uniquely balances 16 V output headroom, integrated dual-FET switching, and direct PWM dimming - making it optimal for compact dual-display systems where voltage margin and feature integration are critical.
Availability
LM3502SQX-16/NOPB is available at Aetrix Electronics and suitable for cellular phone backlighting, PDA dual-display systems, and portable media player UI illumination requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM3502SQX-16/NOPB 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 decades of expertise in portable power solutions.
The LM3502 product line was designed specifically for low-power, dual-display white LED backlighting in space-constrained portable electronics - emphasizing integration, efficiency, and ease of implementation.
FAQ
What is the maximum output voltage supported by the LM3502SQX-16/NOPB?
The LM3502SQX-16/NOPB has a factory-set over-voltage protection (OVP) threshold of 14.0–16.5 V, with nominal regulation at 16 V. This limits the maximum safe output voltage to protect the internal FETs, external Schottky diode, and LED strings. Exceeding this range triggers immediate OVP shutdown - the device does not regulate beyond 16 V, and the OVP off-threshold is 14.0–16.0 V to allow hysteresis recovery.
How does the LM3502SQX-16/NOPB implement dual-display control?
The LM3502SQX-16/NOPB uses two dedicated enable pins - En1 controls the internal PMOS FET (P1) for the MAIN LED string between VOUT1 and VOUT2, while En2 controls the internal NMOS FET (N2) for the SUB string between VOUT2 and Fb. Logic thresholds (≤0.3 V = ON for respective FET) allow independent on/off sequencing of both displays without external switches - all managed within the LM3502SQX-16/NOPB.
Can the LM3502SQX-16/NOPB be dimmed using a microcontroller PWM signal?
Yes - the LM3502SQX-16/NOPB accepts direct PWM signals on the Cntrl pin without external RC filtering. For optimal linearity and minimal audible noise, TI recommends 200–500 Hz PWM frequency. Pulse widths shorter than 12 ms maintain soft-start state for fast recovery; longer low pulses trigger full shutdown and reset soft-start - ensuring robust dimming control across the full duty cycle range.
What package type and thermal characteristics does the LM3502SQX-16/NOPB use?
The LM3502SQX-16/NOPB uses a 16-pin WQFN package (3 mm × 3 mm, 0.8 mm height, TI code RGH0016A) with an exposed die attach pad (DAP) that must be soldered to the PCB ground plane. Its junction-to-ambient thermal resistance (θJA) is 49°C/W, enabling reliable operation up to +125°C junction temperature - critical for sealed portable enclosures with limited airflow.
Does the LM3502SQX-16/NOPB require external compensation components?
No - the LM3502SQX-16/NOPB is internally compensated and requires no external compensation network. Stability is ensured with only three external passive components: input capacitor (4.7 µF), output capacitor (1 µF), and power inductor (e.g., 22 µH). This eliminates tuning effort, reduces BOM count, and accelerates time-to-market for LED backlight designs using the LM3502SQX-16/NOPB.
LM3502SQX-16/NOPB 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:
- 16V
- Current - Output / Channel:
- 400mA (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)
LM3502SQX-16/NOPB FAQ
1.How can I place an order for LM3502SQX-16/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3502SQX-16/NOPB 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 LM3502SQX-16/NOPB reliable?
The price and inventory of LM3502SQX-16/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3502SQX-16/NOPB is usually 5 days.
3.What payment methods are accepted for LM3502SQX-16/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3502SQX-16/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3502SQX-16/NOPB?
LM3502SQX-16/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3502SQX-16/NOPB 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 LM3502SQX-16/NOPB?
For technical support, including LM3502SQX-16/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3502SQX-16/NOPB requirements.
6.How does Aetrix verify that LM3502SQX-16/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3502SQX-16/NOPB 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 LM3502SQX-16/NOPB meets industry standards.
7.What is the process for return or replacement of LM3502SQX-16/NOPB?
All LM3502SQX-16/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3502SQX-16/NOPB, 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 LM3502SQX-16/NOPB part is unused and in its original packaging.
Return procedure for LM3502SQX-16/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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