My Inquiry
My Account
Texas Instruments LM3502SQX-44/NOPB
- Part No.:
- LM3502SQX-44/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LM3502SQX-44/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,349
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM3502SQX-44/NOPB from Texas Instruments is a 44 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, delivers >80% efficiency at 2–5 LEDs per string, and operates from 2.5 V to 5.5 V input with 1 MHz fixed switching frequency.
For engineers reviewing the LM3502SQX-44/NOPB datasheet, LM3502SQX-44/NOPB pinout, LM3502SQX-44/NOPB application, or LM3502SQX-44/NOPB equivalent, key selection criteria include its 44 V OVP threshold, dual enable logic (En1/En2), feedback voltage of 0.25 V, integrated soft-start, and low-profile 10-bump DSBGA package.
Technical Context
The LM3502SQX-44/NOPB implements a current-mode PWM control architecture with cycle-by-cycle current limiting, over-voltage protection (OVP on/off thresholds: 40.5–43.5 V / 39.0–42.0 V), and under-voltage lockout (UVP: 2.4–2.5 V ON). Its internal power NMOS switch (RDS(ON) = 0.55–1.1 Ω) and dedicated VOUT1/VOUT2 pins support dual-string topology without external MOSFETs.
Control logic enables three operational states: MAIN-only (En1 ≥1.4 V), SUB-only (En2 ≥1.4 V), or both active - all coordinated via Cntrl pin enabling (≥1.4 V) and shutdown delay (8–16 ms). The device enters low-IQ shutdown (6–15 µA) when Cntrl = 1.5 V and both En1/En2 ≤0.3 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 44 V nominal; OVP triggers at 40.5–43.5 V to protect LEDs and output capacitor during open-circuit or failure. |
| Input Voltage Range | 2.5 V to 5.5 V; supports single-cell Li-ion (3.0–4.2 V) and dual-cell alkaline (2.5–3.2 V) battery inputs without regulation loss. |
| Switching Frequency | 1 MHz ±20%; enables use of compact 22 µH inductors and reduces EMI filtering burden in space-constrained handheld PCBs. |
| Feedback Voltage | 0.25 V typical; sets LED current via external resistor (ILED = 0.25 V / RSET), minimizing power loss in current-sense network. |
| Current Limit | 450–1050 mA (typical); varies by version - LM3502-44 uses 750 mA typ at 25°C, sufficient for driving up to 10 white LEDs at 20 mA each. |
| Quiescent Current | 0.1–3 µA in shutdown; 0.5–1 mA non-switching; 1.9–3 mA switching - ensures minimal battery drain in always-on display standby modes. |
| Thermal Resistance | 65 °C/W (θJA, DSBGA); requires direct DAP soldering to PCB ground plane for thermal management in high-current backlight applications. |
Pinout & Package
LM3502SQX-44/NOPB is housed in a 10-bump, 1.5 mm × 1.5 mm, <1 mm height Thin DSBGA package (package number YPA0010) with exposed die attach pad (DAP) for thermal conduction to PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply connection | Accepts 2.5–5.5 V; requires local 4.7 µF ceramic capacitor placed adjacent to minimize input ripple and EMI. |
| Sw | Drain of internal NMOS power switch | Connects to inductor and Schottky diode anode; trace must be short/wide to reduce switching losses and radiated noise. |
| En1 | PMOS FET switch control (MAIN display) | Logic-high (≥1.4 V) disables MAIN segment; internal pull-down keeps MAIN off by default unless actively driven. |
| En2 | NMOS FET switch control (SUB display) | Logic-high (≥1.4 V) disables SUB segment; internal pull-down keeps SUB off by default unless actively driven. |
| Fb | Feedback node for LED current regulation | 0.25 V reference; connects to current-sense resistor to ground - sets precise LED current without external op-amp. |
| Cntrl | Global enable/shutdown control | ≥1.4 V enables operation; ≤0.3 V forces shutdown; internal pull-down ensures safe default OFF state. |
| AGND | Analog ground reference | Must be tied directly to PGND to prevent noise coupling into feedback and control loops. |
| PGND | Power ground return path | Low-impedance connection point for high-frequency switch currents; requires solid copper pour beneath DAP. |
| VOUT1 | OVP sense node & PMOS source | Connects to cathode of output Schottky diode and high-side LED string; senses output for 44 V OVP protection. |
| VOUT2 | Drain of internal PMOS/NMOS bypass FETs | Used for SUB display segmentation; if unused, must be left floating or terminated per datasheet guidance (100 nF recommended). |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent display control | Separate En1/En2 pins enable hardware-selectable MAIN/SUB backlight segments without microcontroller GPIO overhead. |
| PWM dimming without RC filter | Direct Cntrl-pin PWM interface (200–500 Hz optimal) eliminates external filtering components and enables fast brightness transitions. |
| Integrated protection suite | Includes OVP (44 V), UVP (2.4 V), thermal shutdown, and cycle-by-cycle current limit - eliminates need for discrete protection ICs. |
| Low-profile DSBGA packaging | 10-bump, 1.5×1.5 mm, <1 mm height package fits ultra-thin mobile devices where Z-height is constrained. |
| No external compensation required | Stable operation with only input/output capacitors and inductor - reduces BOM count and layout sensitivity across production lots. |
Applications
| Smartphone Dual-Display Backlight | Tablet Main/Sub Screen Control |
|---|---|
|
Use Scenario: Simultaneous illumination of primary LCD and secondary status OLED in foldable smartphones. IC Role / Device Role / Timing Role: Step-up regulator with dual-FET bypass logic managing two independent LED strings at 44 V output. Use Value: Enables dynamic power allocation between displays using En1/En2 logic, reducing system-level power management complexity. |
Use Scenario: Adaptive backlighting for tablet main screen and detachable keyboard backlight panel. IC Role / Device Role / Timing Role: Single-chip solution delivering regulated 44 V to two physically separated LED arrays with independent on/off control. Use Value: Eliminates need for two separate boost drivers, saving PCB area and component cost while maintaining timing-synchronized dimming. |
| Portable Medical Display | Industrial Handheld Terminal |
|
Use Scenario: High-reliability backlight for diagnostic-grade medical monitor with redundant display zones. IC Role / Device Role / Timing Role: Current-regulated 44 V boost converter with OVP/UVP/thermal protection ensuring fail-safe LED operation. Use Value: Built-in protections meet IEC 60601-1 safety requirements for patient-connected equipment without added circuitry. |
Use Scenario: Ruggedized field terminal requiring daylight-readable display with extended battery life. IC Role / Device Role / Timing Role: Efficient 1 MHz boost converter driving 8–10 white LEDs at 20 mA per string from 3.3 V rail. Use Value: >80% efficiency across 2.5–5.5 V input range extends runtime; DSBGA package withstands mechanical shock and thermal cycling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED boost driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3502SQX-35/NOPB | 35 V OVP threshold; lower current limit (450–1050 mA same, but optimized for 35 V max output) | Suitable for 7–9 LED strings with lower forward voltage; not rated for 44 V open-circuit conditions | Select when maximum output voltage requirement is ≤35 V and board layout allows same DSBGA footprint. |
| TPS61165DRVR | 40 V OVP; integrated 1.2 A switch; requires external PWM dimming circuitry; WQFN-10 package | Lacks dual-display enable logic; designed for single-string applications with analog + PWM dimming | Choose for higher current capability (1.2 A) and analog dimming flexibility, but expect added layout and control complexity. |
Compared with LM3502SQX-44/NOPB, the LM3502SQX-35/NOPB offers reduced output headroom but identical pinout and control logic, while TPS61165DRVR provides higher drive strength at the cost of losing hardware-based dual-string segmentation.
Availability
LM3502SQX-44/NOPB is available at Aetrix Electronics and suitable for smartphone backlighting, portable medical displays, and industrial handheld terminals requiring stable component supply and long-term manufacturability.
Supply support for LM3502SQX-44/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 automotive and industrial qualification expertise.
The LM3502 product line was engineered specifically for space-constrained, battery-powered white LED backlighting in dual-display portable electronics - prioritizing integration, efficiency, and robust protection.
FAQ
What is the maximum output voltage supported by the LM3502SQX-44/NOPB?
The LM3502SQX-44/NOPB is configured for 44 V nominal output with over-voltage protection triggering between 40.5 V and 43.5 V. This rating enables reliable operation with 10-white-LED strings (typically ~3.2 V per LED × 10 = 32 V forward) while providing margin for temperature drift and tolerance stack-up. The device will cease switching if output exceeds the OVP threshold to protect LEDs and external components.
How does the LM3502SQX-44/NOPB implement dual-display control?
The LM3502SQX-44/NOPB uses two dedicated enable pins - En1 controls the MAIN display segment between VOUT1 and VOUT2, while En2 controls the SUB segment between VOUT2 and Fb. Each pin has internal pull-down resistors, so both displays remain off until actively enabled. When En1 ≥1.4 V and En2 ≤0.3 V, only MAIN illuminates; reversing the logic activates SUB alone. Both high enables simultaneous operation.
Can the LM3502SQX-44/NOPB be dimmed using PWM without external filtering components?
Yes, the LM3502SQX-44/NOPB supports direct PWM dimming via its Cntrl pin without RC filters. For optimal linearity, apply 200–500 Hz PWM signals; low-time durations under 12 ms preserve soft-start state for rapid recovery, while longer low-times trigger full shutdown and reset. This eliminates passive components and simplifies firmware control in resource-constrained microcontrollers.
What thermal considerations apply to the LM3502SQX-44/NOPB in continuous operation?
The LM3502SQX-44/NOPB has a junction-to-ambient thermal resistance (θJA) of 65 °C/W in its DSBGA package. To maintain safe operation below 125 °C junction temperature, the DAP must be soldered to a large PCB ground plane. At 750 mA load and 5.5 V input, power dissipation reaches ~0.4 W - requiring ≥2 cm² of 2-oz copper under the DAP to limit temperature rise to ~26 °C above ambient.
Is the LM3502SQX-44/NOPB compatible with ceramic output capacitors?
Yes, the LM3502SQX-44/NOPB's over-voltage protection architecture allows safe use of low-ESR ceramic capacitors at the output. Unlike unregulated boost converters, its 44 V OVP threshold prevents destructive overvoltage during LED string removal or open-circuit faults - eliminating the need for bulk electrolytic capacitors and enabling smaller, more reliable designs.
LM3502SQX-44/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:
- 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)
LM3502SQX-44/NOPB FAQ
1.How can I place an order for LM3502SQX-44/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3502SQX-44/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-44/NOPB reliable?
The price and inventory of LM3502SQX-44/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-44/NOPB is usually 5 days.
3.What payment methods are accepted for LM3502SQX-44/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3502SQX-44/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3502SQX-44/NOPB?
LM3502SQX-44/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3502SQX-44/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-44/NOPB?
For technical support, including LM3502SQX-44/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3502SQX-44/NOPB requirements.
6.How does Aetrix verify that LM3502SQX-44/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3502SQX-44/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-44/NOPB meets industry standards.
7.What is the process for return or replacement of LM3502SQX-44/NOPB?
All LM3502SQX-44/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3502SQX-44/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-44/NOPB part is unused and in its original packaging.
Return procedure for LM3502SQX-44/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3502SQX-44/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…
