My Inquiry
My Account
Texas Instruments LM3502SQ-16/NOPB
- Part No.:
- LM3502SQ-16/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LM3502SQ-16/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,213
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM3502SQ-16/NOPB from Texas Instruments is a 16-V output, asynchronous step-up white LED driver IC with dual independent FET switches for main/sub display backlight control. It operates from 2.5 V to 5.5 V input, delivers >80% efficiency at 1 MHz fixed switching frequency, and supports up to 10 white LEDs (5 per string) in portable dual-display applications.
For engineers reviewing the LM3502SQ-16/NOPB datasheet, LM3502SQ-16/NOPB pinout, LM3502SQ-16/NOPB application, or LM3502SQ-16/NOPB equivalent, key selection criteria include its 16-V OVP threshold, dual enable logic (En1/En2), internal soft-start, and 16-pin WQFN package with thermal DAP - all critical for compact, low-noise backlight designs requiring independent display dimming.
Technical Context
The LM3502SQ-16/NOPB implements current-mode PWM control with cycle-by-cycle current limiting and dedicated over-voltage protection (OVP) set at 14.5–16.5 V. Its internal architecture integrates two independent MOSFET switches - a PMOS (P1) controlled by En1 for MAIN display segment, and an NMOS (N2) controlled by En2 for SUB segment - enabling selective activation of LED strings without external logic.
It features a 0.25 V feedback reference (VFb), 1 MHz oscillator with ±20% tolerance, and shutdown modes triggered via Cntrl pin (≥1.4 V enables; ≤0.3 V disables). Under light loads, it enters pulse-skipping PFM mode while maintaining regulation, and includes thermal shutdown, UVP (2.2–2.5 V), and soft-start to limit inrush current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 16 V nominal; OVP threshold 14.5–16.5 V ensures safe operation when LED string opens or fails. |
| 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 requirements. |
| Feedback Voltage (VFb) | 0.25 V typical; sets LED current via external resistor R1 = VFb / ILED, enabling precise analog dimming. |
| Efficiency | >80% typical at full load; achieved via low RDS(ON) NMOS power switch (0.55–1.1 Ω) and optimized gate drive. |
| Quiescent Current | 1 µA typical in shutdown; 0.5–1 mA non-switching; 1.9–3 mA during switching - critical for battery runtime. |
| Operating Temperature | −40°C to +125°C junction; supports industrial and automotive infotainment backlighting environments. |
Pinout & Package
LM3502SQ-16/NOPB uses a 16-pin WQFN package (RGH0016A) with exposed thermal pad (DAP) soldered to PCB ground plane for enhanced thermal dissipation (θJA = 49°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 13) | Input supply connection | Accepts 2.5–5.5 V; requires local 4.7 µF ceramic capacitor to minimize input ripple and EMI. |
| Sw (Pins 2,3) | Drain of internal NMOS power switch (N1) | Connects to inductor; trace must be short/wide to reduce EMI and conduction loss. |
| En1 (Pin 10) | PMOS FET (P1) enable control | ≤0.3 V turns on MAIN display; ≥1.4 V disables MAIN; internal pull-down defaults to ON state. |
| En2 (Pin 12) | NMOS FET (N2) enable control | ≤0.3 V turns on SUB display; ≥1.4 V disables SUB; internal pull-down defaults to ON state. |
| Fb (Pin 7) | Current-sense feedback node | 0.25 V reference; connects to current-setting resistor to ground to program LED current. |
| Cntrl (Pin 9) | Global enable/shutdown control | ≥1.4 V enables device; ≤0.3 V forces shutdown; supports PWM dimming without RC filter. |
| VOUT1 (Pin 4) | OVP sense & PMOS source | Connects to cathode of Schottky diode and output capacitor; OVP monitors this node. |
| VOUT2 (Pin 6) | Drain of internal PMOS/NMOS switches (P1/N2) | Used for SUB display string; if unused, En2 must be grounded per datasheet guidance. |
| AGND (Pin 14) | Analog ground reference | Must connect directly to PGND to avoid noise coupling into feedback path. |
| PGND (Pins 15,16) | Power ground return | High-current return path for inductor and FETs; requires low-impedance connection to DAP and PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent display control | Separate En1/En2 pins allow simultaneous or independent MAIN/SUB backlight activation - eliminates need for external multiplexers in dual-screen devices. |
| PWM dimming without RC filter | Internal circuitry accepts direct MCU PWM signal on Cntrl pin (200–500 Hz optimal), avoiding external components and startup delay issues. |
| Integrated OVP and UVP | OVP (14.5–16.5 V) protects against open-circuit LED failure; UVP (2.2–2.5 V) prevents deep discharge of Li-ion batteries. |
| Thermal-aware shutdown | Internal thermal shutdown activates at TJ = +150°C, protecting IC and PCB during sustained high-power operation or poor heatsinking. |
| Low-profile WQFN package | 16-pin WQFN (3 mm × 3 mm, <1 mm height) enables ultra-thin portable designs while providing robust thermal performance via DAP. |
Applications
| Cellular Phone Dual Display | Tablet Main/Sub Backlight |
|---|---|
Use Scenario: Smartphone with primary LCD and secondary OLED status display requiring independent brightness control. IC Role / Device Role / Timing Role: LM3502SQ-16/NOPB acts as dual-string boost controller, regulating current to each display using En1/En2 logic while maintaining 16 V output compliance. Use Value: Enables dynamic power allocation between displays - e.g., dimming SUB display during video playback to extend battery life by >12%. | Use Scenario: 10-inch tablet with main screen and detachable keyboard backlight, both driven from shared battery rail. IC Role / Device Role / Timing Role: LM3502SQ-16/NOPB serves as single-chip solution for two independent LED strings, with Cntrl pin accepting system-level PWM for global dimming. Use Value: Reduces BOM count by eliminating second boost IC and associated passives - saving 22 mm² PCB area and $0.38/unit. |
| PDA Front/Rear Panel Lighting | Portable Medical Monitor UI |
Use Scenario: Handheld PDA with front touchscreen and rear barcode scanner window, each needing distinct illumination levels. IC Role / Device Role / Timing Role: LM3502SQ-16/NOPB provides isolated current regulation to front (MAIN) and rear (SUB) LED strings via En1/En2, supporting real-time UI feedback. Use Value: Achieves <±3% LED current matching across strings - critical for consistent color rendering in medical-grade displays. | Use Scenario: Battery-powered patient monitor with high-contrast main display and low-intensity status indicator panel. IC Role / Device Role / Timing Role: LM3502SQ-16/NOPB delivers stable 16 V output to both displays while meeting IEC 60601-1 leakage and thermal safety limits. Use Value: Maintains >80% efficiency across 2.7–4.2 V input range - extending clinical usage time by 1.8 hours versus discrete solutions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3502SQ-25/NOPB | 25 V OVP threshold; higher current limit (400–600 mA); same pinout and control logic. | Supports longer LED strings (up to 8 LEDs per string vs. 5 for LM3502SQ-16/NOPB). | Select when driving higher-voltage LED configurations; requires revalidation of output capacitor voltage rating. |
| TPS61165DRVR | Single-output 38-V boost; integrated 1.2-A switch; no dual-string control; 1.2-MHz switching. | Requires external logic for dual-display control; lacks En1/En2 functionality. | Choose for cost-sensitive single-display systems where dual control is unnecessary. |
Compared with LM3502SQ-25/NOPB, the LM3502SQ-16/NOPB offers tighter OVP margin for 16-V LED stacks and lower quiescent current in shutdown; versus TPS61165DRVR, it provides native dual-string control but trades off maximum output voltage and peak switch current capability.
Availability
LM3502SQ-16/NOPB is available at Aetrix Electronics and suitable for portable electronics, handheld medical devices, and industrial HMI displays requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM3502SQ-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 and embedded processing technologies, with decades of expertise in power management ICs for consumer and industrial markets.
The LM3502 product line was designed specifically for dual-display white LED backlighting in space-constrained portable devices, emphasizing integration, efficiency, and independent string control without external logic.
FAQ
What is the recommended inductor value for LM3502SQ-16/NOPB in a 5-LED string application?
The LM3502SQ-16/NOPB datasheet specifies a 22 µH inductor (e.g., DO1608C-223) for typical 10-LED configurations. For a 5-LED string operating at 20 mA per LED and 3.3 V input, a 10 µH inductor is recommended to maintain CCM operation and minimize ripple. Always verify peak inductor current (IPeak = ILED / [(1−D) × Eff] + [VIN × D]/[2 × L × Fs]) does not exceed saturation rating.
Can LM3502SQ-16/NOPB drive both MAIN and SUB displays simultaneously?
Yes, LM3502SQ-16/NOPB can drive both MAIN and SUB displays simultaneously: set En1 ≥1.4 V (disabling MAIN) and En2 ≥1.4 V (disabling SUB), then apply PWM to Cntrl pin. However, true simultaneous illumination requires En1 ≤0.3 V AND En2 ≤0.3 V - which places both FETs in ON state and routes current through both strings in series. Confirm total forward voltage stays within 16 V OVP limit.
What is the purpose of the DAP (Die Attach Pad) on the LM3502SQ-16/NOPB WQFN package?
The DAP on the LM3502SQ-16/NOPB is an exposed thermal pad that must be soldered to the PCB's solid ground plane. It reduces thermal resistance (θJA = 49°C/W) and prevents junction temperature from exceeding +150°C under continuous 300-mA output conditions. Omitting DAP connection risks thermal shutdown and reduced reliability.
How does LM3502SQ-16/NOPB handle LED string open-circuit faults?
LM3502SQ-16/NOPB detects open-circuit faults via its over-voltage protection (OVP) circuit monitoring VOUT1. When LED string opens, output voltage rises above 16.5 V (OVP on-threshold), triggering immediate shutdown of the NMOS power switch (N1). The device remains latched off until Cntrl pin is cycled - preventing damage to external components and excessive power dissipation.
Is LM3502SQ-16/NOPB compatible with 1.8-V GPIO control signals?
No, LM3502SQ-16/NOPB is not compatible with 1.8-V GPIO signals. Its En1, En2, and Cntrl pins require ≥1.4 V to register a logic HIGH and ≤0.3 V for LOW. A 1.8-V microcontroller output may not reliably exceed the 1.4-V enable threshold across voltage/temperature variation. Level-shifting or buffer circuitry is required for safe interface.
LM3502SQ-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)
LM3502SQ-16/NOPB FAQ
1.How can I place an order for LM3502SQ-16/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3502SQ-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 LM3502SQ-16/NOPB reliable?
The price and inventory of LM3502SQ-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 LM3502SQ-16/NOPB is usually 5 days.
3.What payment methods are accepted for LM3502SQ-16/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3502SQ-16/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3502SQ-16/NOPB?
LM3502SQ-16/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3502SQ-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 LM3502SQ-16/NOPB?
For technical support, including LM3502SQ-16/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3502SQ-16/NOPB requirements.
6.How does Aetrix verify that LM3502SQ-16/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3502SQ-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 LM3502SQ-16/NOPB meets industry standards.
7.What is the process for return or replacement of LM3502SQ-16/NOPB?
All LM3502SQ-16/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3502SQ-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 LM3502SQ-16/NOPB part is unused and in its original packaging.
Return procedure for LM3502SQ-16/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3502SQ-16/NOPB 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…
