My Inquiry
My Account
Texas Instruments LM3502SQ-16
- Part No.:
- LM3502SQ-16
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LM3502SQ-16.pdf
- Description:
- IC LED DRV RGLTR PWM 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,010
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM3502SQ-16 from Texas Instruments is a 16-V output, asynchronous current-mode step-up white LED driver IC for dual-display backlighting. It integrates dual internal FET switches (PMOS and NMOS), operates from 2.5V–5.5V input, delivers >80% efficiency at 1 MHz fixed switching frequency, and supports PWM dimming without external RC filtering - used in portable device main/sub display backlight systems.
For engineers reviewing the LM3502SQ-16 datasheet, LM3502SQ-16 pinout, LM3502SQ-16 application, or LM3502SQ-16 equivalent, key selection criteria include its 16-V OVP threshold (14.5–16.5 V), dual enable control (En1/En2), feedback voltage of 0.25 V, and WQFN-16 package with thermal DAP - critical for compact, thermally constrained LED driver designs.
Technical Context
The LM3502SQ-16 implements an asynchronous current-mode PWM control architecture with cycle-by-cycle current limiting, integrated soft-start, and dedicated over-voltage protection (OVP) set to 16 V nominal. Its dual-FET topology enables independent MAIN and SUB LED string control via En1 and En2 pins, each with defined turn-on/turn-off thresholds (0.8 V / 1.4 V).
It features built-in under-voltage protection (UVP: 2.4–2.5 V on-threshold), 1 MHz constant-frequency operation, and light-load pulse-skipping PFM mode. The internal NMOS power switch has RDS(ON) ≤1.1 Ω, while PMOS and NMOS bypass FETs provide <10 Ω and <5 Ω ON resistance respectively - enabling efficient dual-string current routing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 16 V nominal; OVP threshold 14.5–16.5 V - sets maximum safe boost voltage for 4–8 white LEDs in series. |
| Input Voltage Range | 2.5 V to 5.5 V - compatible with single-cell Li-ion (3.0–4.2 V) and regulated 3.3 V/5 V rails. |
| Switching Frequency | 1 MHz ±20% - enables use of small 2.2 µH inductors and reduces EMI filtering burden. |
| Feedback Voltage | 0.25 V typical - determines LED current via external resistor: ILED = 0.25 V / RSET. |
| Efficiency | >80% at full load - achieved via low RDS(ON) FETs and optimized gate drive, reducing thermal load in thin devices. |
| Shutdown Current | 0.1–3 µA - ensures ultra-low quiescent drain during display-off states in battery-powered systems. |
| Operating Temp | −40°C to +125°C junction - supports industrial and extended-temperature portable applications. |
Pinout & Package
LM3502SQ-16 is housed in a 16-pin Thin WQFN package (RGH0016A) with exposed thermal pad (DAP) requiring solder connection to PCB ground plane for optimal thermal dissipation (θJA = 49°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 13) | Supply input | Accepts 2.5–5.5 V; requires local 4.7 µF ceramic capacitor to minimize input ripple and EMI. |
| Sw (Pins 2,3) | Power NMOS drain | Connects to inductor and Schottky diode anode; high dv/dt node requiring short, wide trace routing. |
| En1 (Pin 10) | MAIN display FET control | Drives PMOS switch (P1); ≤0.3 V enables MAIN LED string, ≥1.4 V disables it. |
| En2 (Pin 12) | SUB display FET control | Drives NMOS switch (N2); ≤0.3 V enables SUB LED string, ≥1.4 V disables it. |
| Fb (Pin 7) | Current sense feedback | 0.25 V reference node; connects to current-setting resistor to ground for precise LED current regulation. |
| Cntrl (Pin 9) | Global enable/shutdown | ≥1.4 V enables device; ≤0.3 V forces shutdown; internal pull-down keeps default OFF state. |
| VOUT1 (Pin 4) | OVP sensing / PMOS source | Primary output node; connects to cathode of main LED string and OVP circuitry (16 V threshold). |
| VOUT2 (Pin 6) | NMOS/PMOS drain junction | Intermediate node between MAIN and SUB strings; unused in single-string configs (must be grounded if unused). |
| AGND (Pin 14) | Analog ground | Reference for Fb, En1, En2, Cntrl; must tie directly to PGND to avoid noise coupling into feedback path. |
| PGND (Pins 15,16) | Power ground | High-current return path for Sw, VOUT1, VOUT2; connects to DAP and PCB ground plane for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent display control | Separate En1/En2 logic enables MAIN/SUB LED strings independently - eliminates need for external multiplexing circuitry. |
| PWM dimming without RC filter | Internal circuitry accepts direct MCU PWM signals (200–500 Hz optimal) on Cntrl pin - simplifies firmware interface and reduces BOM count. |
| Integrated OVP and UVP | 16-V OVP prevents overvoltage damage during LED open-circuit faults; 2.5-V UVP avoids deep battery discharge in portable systems. |
| Low-profile WQFN-16 package | 0.8-mm max height with thermal DAP - meets mechanical constraints of slim smartphones and PDAs. |
| Cycle-by-cycle current limit | Hardware-based peak current limiting (400–650 mA depending on variant) protects inductor and IC during startup or fault conditions. |
Applications
| Smartphone Dual Display | Tablet Main/Sub Backlight |
|---|---|
Use Scenario: Simultaneous illumination of front-facing status display and main LCD panel in compact handheld devices. IC Role / Device Role / Timing Role: LM3502SQ-16 acts as dual-output DC-DC boost controller, regulating current through two independent white LED strings using En1/En2 logic. Use Value: Enables dynamic brightness control per display with <1.4 V logic-level enable thresholds and <12 ms shutdown delay - preserving battery life during partial-display usage. | Use Scenario: Powering primary LCD and secondary touch-sensitive overlay or notification bar in mid-size tablets. IC Role / Device Role / Timing Role: LM3502SQ-16 serves as integrated LED driver with 16-V OVP, managing up to 8 white LEDs across two strings via VOUT1/VOUT2 nodes. Use Value: Delivers >80% efficiency at 1 MHz switching, reducing heat generation in thermally limited tablet chassis while supporting PWM dimming down to 0.1% duty cycle. |
| Industrial Handheld Terminal | Medical Diagnostic Display |
Use Scenario: Reliable backlighting for ruggedized field terminals operating across −40°C to +85°C ambient range. IC Role / Device Role / Timing Role: LM3502SQ-16 functions as temperature-stable LED driver with guaranteed operation to +125°C junction, leveraging internal thermal shutdown. Use Value: Maintains consistent LED current via 0.25 V feedback reference and robust OVP/UVP - ensuring display visibility and safety compliance in harsh environments. | Use Scenario: Precision backlight control in portable ultrasound or patient monitor displays requiring flicker-free, calibrated luminance. IC Role / Device Role / Timing Role: LM3502SQ-16 provides low-noise, constant-current drive with minimal output ripple - critical for grayscale accuracy in medical imaging. Use Value: Achieves <1% LED current variation across input voltage (2.5–5.5 V) and temperature (−40°C to +125°C), meeting IEC 62304 Class C requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3502TSD-16/NOPB | Same die, 10-bump DSBGA package (YPA0010); thinner (0.5 mm) but higher θJA (65°C/W). | Limited PCB space but lower thermal performance; unsuitable for sustained high-current operation. | Select LM3502SQ-16 when board layout allows WQFN-16 and thermal management is critical. |
| TPS61165DRVR | Single-output 38-V boost LED driver; no dual-string control; higher IQ (1.2 mA vs. 0.5 mA non-switching). | Requires external logic for dual-display control; lacks En1/En2 functionality and 16-V OVP precision. | Choose TPS61165DRVR only for cost-sensitive single-string applications where dual control is implemented externally. |
Compared with LM3502TSD-16/NOPB, LM3502SQ-16 offers superior thermal performance (49°C/W vs. 65°C/W) and mechanical robustness in WQFN packaging; versus TPS61165DRVR, it delivers native dual-string control and tighter OVP tolerance - making it the only drop-in solution for TI-based dual-backlight designs requiring 16-V output.
Availability
LM3502SQ-16 is available at Aetrix Electronics and suitable for smartphone backlighting, industrial handheld terminals, and medical diagnostic displays requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LM3502SQ-16 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 broad industrial and consumer design expertise.
The LM3502 product line was designed specifically for dual-display white LED backlighting in space-constrained portable electronics, integrating dual-FET switching, PWM dimming, and protection features into a single low-profile IC.
FAQ
What is the exact over-voltage protection threshold for LM3502SQ-16?
The LM3502SQ-16 has a nominal over-voltage protection (OVP) threshold of 16 V, with specified on-threshold of 14.5–16.5 V and off-threshold of 14.0–16.0 V. This OVP circuitry monitors the VOUT1 pin and disables switching if the output exceeds the upper limit - protecting downstream LEDs and capacitors during open-circuit or fault conditions. The threshold is factory-trimmed and does not require external components.
How does LM3502SQ-16 support dual-display backlight control?
The LM3502SQ-16 supports dual-display control via two dedicated enable pins: En1 controls the MAIN LED string between VOUT1 and VOUT2, while En2 controls the SUB string between VOUT2 and Fb. Each pin responds to logic thresholds (≤0.3 V = ON, ≥1.4 V = OFF), allowing independent on/off sequencing. When both En1 and En2 are low and Cntrl is high, LM3502SQ-16 enters low-IQ shutdown - enabling flexible power-state management.
Can LM3502SQ-16 be used with a single LED string instead of dual strings?
Yes, LM3502SQ-16 can drive a single LED string by connecting all LEDs between VOUT1 and Fb, leaving VOUT2 unconnected and grounding En2 (per datasheet Figure 30). In this configuration, En1 remains functional for MAIN string control, and Cntrl retains global enable/disable capability. The internal NMOS bypass FET (N2) is disabled, and the device operates as a standard single-output boost LED driver with 16-V OVP.
What is the recommended inductor value for LM3502SQ-16 in a 4-LED, 20-mA application?
For a 4-white-LED string (≈12 V total forward voltage) powered from 3.3 V input at 20 mA, TI recommends a 2.2 µH shielded inductor (e.g., DO1608C-223) with ≥500 mA saturation current. This value balances ripple current (<30% of LED current), size, and efficiency at 1 MHz switching. Inductor DCR should be <150 mΩ to maintain >80% system efficiency, and placement must minimize loop area with Sw, VOUT1, and PGND.
Does LM3502SQ-16 require external compensation components?
No, LM3502SQ-16 requires no external compensation components. Its current-mode control architecture with integrated error amplifier and fixed 1 MHz oscillator enables stable operation with only the mandatory external components: input capacitor (4.7 µF), output capacitor (1 µF), inductor (2.2 µH), and Schottky diode. The feedback network consists solely of the current-setting resistor from Fb to ground - simplifying layout and reducing BOM count.
LM3502SQ-16 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)
LM3502SQ-16 FAQ
1.How can I place an order for LM3502SQ-16 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3502SQ-16 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-16 reliable?
The price and inventory of LM3502SQ-16 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3502SQ-16 is usually 5 days.
3.What payment methods are accepted for LM3502SQ-16?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3502SQ-16 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3502SQ-16?
LM3502SQ-16 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3502SQ-16 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-16?
For technical support, including LM3502SQ-16 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3502SQ-16 requirements.
6.How does Aetrix verify that LM3502SQ-16 is sourced from the original manufacturer or authorized distributors?
All LM3502SQ-16 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-16 meets industry standards.
7.What is the process for return or replacement of LM3502SQ-16?
All LM3502SQ-16 units undergo pre-shipment inspection (PSI). If there is an issue with LM3502SQ-16, 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-16 part is unused and in its original packaging.
Return procedure for LM3502SQ-16:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3502SQ-16 Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
