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Texas Instruments LM3503ITLX-44/NOPB
- Part No.:
- LM3503ITLX-44/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 10-WFBGA, DSBGA
- Datasheet:
-
LM3503ITLX-44/NOPB.pdf
- Description:
- IC LED DRVR RGLTR PWM 10TUSMD
- Quantity:
- Payment:
- Shipping:
Inventory:2,930
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Product details
Overview
LM3503ITLX-44/NOPB from Texas Instruments is a dual-display constant-current white LED driver IC with analog brightness control, 44 V over-voltage protection, 1 MHz switching frequency, and support for up to 10 LEDs (5 per display). It operates from 2.5 V to 5.5 V input and delivers >80% peak efficiency in portable backlighting applications.
For engineers reviewing the LM3503ITLX-44/NOPB datasheet, LM3503ITLX-44/NOPB pinout, LM3503ITLX-44/NOPB application, or LM3503ITLX-44/NOPB equivalent, key selection considerations include its dual independent enable logic (En1/En2), internal NMOS/PMOS FET switch architecture, analog-controlled current regulation via Cntrl pin (0.2–3.5 V), and fixed 44 V OVP threshold - critical for robust dual-string LED backlight design in space-constrained handheld devices.
Technical Context
The LM3503ITLX-44/NOPB implements an asynchronous current-mode PWM controller with cycle-by-cycle current limiting, dedicated UVP (2.4 V on-threshold) and OVP (40.5–43.5 V on-threshold), soft-start, and thermal shutdown. Its dual-FET topology enables independent MAIN (VOUT1–VOUT2) and SUB (VOUT2–Fb) string control using En1 and En2 pins with defined logic thresholds (≤0.3 V = ON for PMOS/NMOS switches).
It features a 1 MHz fixed-frequency oscillator, no external compensation requirement, and integrated feedback error amplifier with 0.55 V typical VFb. The device supports both continuous and discontinuous conduction modes, with maximum duty cycle limited to 95% and RDS(ON) of 0.55 Ω (NMOS N1) and 5 Ω (PMOS P1) at specified test conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output OVP Threshold | 40.5–43.5 V - protects LED strings and output capacitor during open-circuit or LED failure in 44 V variant. |
| Switching Frequency | 0.8–1.2 MHz - enables compact LC filter design with small inductors (e.g., 2.2 µH) and low-profile ceramic capacitors. |
| 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 in portable systems. |
| Feedback Voltage (VFb) | 0.5–0.6 V - sets LED current via external resistor; stable across −40°C to +125°C junction temperature range. |
| Current Limit (ICL) | 450–1050 mA - programmable peak inductor current limit ensures safe operation under shorted-output or high-VF LED conditions. |
| Quiescent Current (IQ) | 0.1–3 µA in shutdown, 0.5–1 mA non-switching - minimizes battery drain in always-on display standby states. |
| Efficiency | >80% peak - achieved with low RDS(ON) FETs and optimized gate drive, reducing thermal load in thin-profile DSBGA packages. |
Pinout & Package
LM3503ITLX-44/NOPB uses a 10-bump thin DSBGA package (YPA0010), height <1 mm, with die attach pad (DAP) soldered to PCB ground plane for thermal dissipation. Pin mapping validated per TI SNVS329E Rev E.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input power supply connection | Accepts 2.5–5.5 V; requires local 4.7 µF ceramic capacitor to minimize input ripple and EMI. |
| Sw | Drain of internal NMOS power switch (N1) | Connects to inductor; low-inductance trace routing essential to limit voltage spikes and EMI radiation. |
| En1 / En2 | PMOS/NMOS FET enable inputs | Logic-controlled MAIN/SUB display activation; ≤0.3 V = ON, ≥1.4 V = OFF; internal pull-down ensures default OFF state. |
| Fb | Feedback voltage sensing node | Monitors regulated LED current via external resistor; 0.55 V nominal reference enables precise current setting. |
| Cntrl | Analog brightness control input | 0.2–3.5 V DC input linearly scales LED current; supports RC-filtered PWM dimming when driven externally. |
| VOUT1 / VOUT2 | Output nodes for MAIN and SUB LED strings | VOUT1 = source of PMOS (P1); VOUT2 = drain of NMOS (N2)/PMOS (P1); 100 nF cap recommended at VOUT2 if unused. |
| AGND / PGND | Analog and power ground returns | Must be connected directly together near device; PGND carries high di/dt currents, AGND references sensitive analog circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent display control | Separate En1/En2 logic enables MAIN/SUB backlight sequencing without external logic or MCU GPIO overhead. |
| Fixed 44 V over-voltage protection | Hardware-enforced OVP threshold eliminates need for external crowbar or Zener clamping in high-VF LED stacks. |
| 1 MHz constant-frequency PWM | Enables use of miniature 2.2 µH inductors and avoids audible noise in audio-sensitive portable designs. |
| No external compensation required | Reduces BOM count and layout sensitivity; simplifies design validation and production ramp for consumer OEMs. |
| Internal soft-start | Prevents inrush current into output capacitor during power-up, avoiding voltage droop on shared system rails. |
Applications
| Cellular Phone Main/Sub Display | PDA Dual-Screen Backlight |
|---|---|
Use Scenario: Simultaneous illumination of primary LCD and secondary status OLED in clamshell or slider phones. IC Role / Device Role / Timing Role: Constant-current dual-channel LED driver with independent enable control and analog dimming. Use Value: Enables seamless transition between main and sub displays using only two GPIOs and one analog control line, reducing MCU resource usage. | Use Scenario: Powering front-panel main LCD and rear-panel touch-sensitive keypad backlight in enterprise PDAs. IC Role / Device Role / Timing Role: High-efficiency step-up converter with 44 V OVP protecting against LED open-circuit faults in dual-string configuration. Use Value: Eliminates need for discrete OVP circuitry, saving PCB area and improving reliability in compact handheld form factors. |
| Portable Media Player UI Backlight | Smartwatch Dual-Zone Illumination |
Use Scenario: Driving 4–6 white LEDs for main screen and 2–4 for navigation button ring in battery-powered media players. IC Role / Device Role / Timing Role: Analog-brightness-controlled current source with 1 MHz switching and <1 mm profile. Use Value: Achieves >80% efficiency at 3.6 V input, extending playback time while maintaining ultra-thin mechanical stack-up. | Use Scenario: Independent brightness control of circular display segment and status indicator zone in round-form-factor smartwatches. IC Role / Device Role / Timing Role: Low-quiescent-current dual-output LED driver with shutdown mode (0.1 µA) for extended sleep periods. Use Value: Supports always-on display functionality with minimal battery drain, leveraging En1/En2 logic for zone-selective wake-up. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-display LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3503ITLX-25/NOPB | 25 V OVP threshold; lower ICL (400–800 mA); identical pinout and control interface | Suitable for 4–6 LED strings with lower total forward voltage; not safe for 44 V-rated LED configurations | Select when VF × NLED ≤ 23 V; reduces cost where full 44 V margin is unnecessary |
| TPS61165DRVR | Single-output, 40 V OVP, I²C programmable, 1.2 MHz switching, WQFN-16 package | Lacks dual independent enable logic; requires MCU firmware for multi-zone control | Choose for designs needing digital dimming granularity or higher integration; not drop-in for En1/En2 hardware sequencing |
Compared with LM3503ITLX-25/NOPB, the LM3503ITLX-44/NOPB provides 19 V higher OVP headroom for fault tolerance in high-VF LED stacks, while TPS61165DRVR trades hardware dual-zone control for software-configurable flexibility - making LM3503ITLX-44/NOPB optimal for deterministic, low-latency dual-display enable timing without MCU intervention.
Availability
LM3503ITLX-44/NOPB is available at Aetrix Electronics and suitable for cellular phone backlighting, PDA dual-screen systems, and portable media player UI illumination requiring stable component supply and long-term industrial availability.
Supply support for LM3503ITLX-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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.
The LM3503 product line was designed specifically for dual-display white LED backlighting in space-constrained portable devices, emphasizing analog dimming fidelity, hardware-based display zoning, and robust fault protection without external components.
FAQ
What is the over-voltage protection threshold for LM3503ITLX-44/NOPB?
The LM3503ITLX-44/NOPB has a factory-trimmed over-voltage protection threshold of 40.5–43.5 V (on-threshold) and 39.0–42.0 V (off-threshold), specific to the -44 variant. This protects the output stage and external LEDs during open-circuit conditions or LED string failure. The threshold is fixed and cannot be adjusted externally.
How does the LM3503ITLX-44/NOPB control LED current for dual displays?
The LM3503ITLX-44/NOPB controls LED current using a single analog Cntrl pin (0.2–3.5 V) that sets the feedback reference voltage (VFb), while En1 and En2 pins independently enable the MAIN (VOUT1–VOUT2) and SUB (VOUT2–Fb) LED strings. This allows hardware-based, glitch-free zoning without MCU involvement - a core feature of the LM3503ITLX-44/NOPB architecture.
Can LM3503ITLX-44/NOPB operate with only one LED string active?
Yes. The LM3503ITLX-44/NOPB supports single-string operation: grounding En2 and driving En1 ≥1.4 V activates only the MAIN display (VOUT1–VOUT2), while floating or grounding En2 and driving En1 ≤0.3 V disables MAIN and enables SUB (VOUT2–Fb) - provided VOUT2 is properly terminated. Both configurations are explicitly supported in the LM3503ITLX-44/NOPB datasheet.
What package type and thermal performance does LM3503ITLX-44/NOPB use?
The LM3503ITLX-44/NOPB uses a 10-bump thin DSBGA package (YPA0010) with <1 mm height and exposed die attach pad (DAP) for thermal conduction. Its junction-to-ambient thermal resistance (θJA) is 65°C/W, enabling operation up to +125°C junction temperature with proper PCB copper pour under the DAP - a key specification for sustained brightness in thermally constrained handheld enclosures.
Does LM3503ITLX-44/NOPB require external compensation components?
No. The LM3503ITLX-44/NOPB integrates internal compensation and requires no external capacitors or resistors for loop stability. This is confirmed in the datasheet's "No External Compensation Required" feature list and validated across all operating conditions (−40°C to +125°C), simplifying layout and eliminating tuning effort for the LM3503ITLX-44/NOPB design.
LM3503ITLX-44/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-WFBGA, DSBGA
- 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:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-TµSMD (1.9x2.07)
LM3503ITLX-44/NOPB FAQ
1.How can I place an order for LM3503ITLX-44/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3503ITLX-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 LM3503ITLX-44/NOPB reliable?
The price and inventory of LM3503ITLX-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 LM3503ITLX-44/NOPB is usually 5 days.
3.What payment methods are accepted for LM3503ITLX-44/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3503ITLX-44/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3503ITLX-44/NOPB?
LM3503ITLX-44/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3503ITLX-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 LM3503ITLX-44/NOPB?
For technical support, including LM3503ITLX-44/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3503ITLX-44/NOPB requirements.
6.How does Aetrix verify that LM3503ITLX-44/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3503ITLX-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 LM3503ITLX-44/NOPB meets industry standards.
7.What is the process for return or replacement of LM3503ITLX-44/NOPB?
All LM3503ITLX-44/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3503ITLX-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 LM3503ITLX-44/NOPB part is unused and in its original packaging.
Return procedure for LM3503ITLX-44/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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