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Texas Instruments LM3503ITL-25/NOPB
- Part No.:
- LM3503ITL-25/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 10-WFBGA, DSBGA
- Datasheet:
-
LM3503ITL-25/NOPB.pdf
- Description:
- IC LED DRVR RGLTR PWM 10TUSMD
- Quantity:
- Payment:
- Shipping:
Inventory:4,357
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Product details
Overview
LM3503ITL-25/NOPB from Texas Instruments is a dual-display constant-current white LED driver with analog brightness control, designed for portable device backlighting. It delivers up to 600 mA peak NMOS switch current (25V OVP version), operates from 2.5V–5.5V input, and integrates two independent FET switches for MAIN/SUB display segmentation in single-string LED networks.
For engineers reviewing the LM3503ITL-25/NOPB datasheet, LM3503ITL-25/NOPB pinout, LM3503ITL-25/NOPB application, or LM3503ITL-25/NOPB equivalent, this page provides verified technical context, package-specific pin functions, real-world efficiency data at 4.2V/15mA, OVP threshold of 22.5–25.5V, and confirmed alternative options for dual-display LED driver selection.
Technical Context
The LM3503ITL-25/NOPB implements an asynchronous current-mode PWM controller with fixed 1 MHz switching frequency and cycle-by-cycle current limiting. Its dual-FET architecture enables independent MAIN (VOUT1–VOUT2) and SUB (VOUT2–Fb) string control via En1/En2 logic pins, supporting dynamic segment enable/disable without external MOSFETs.
It features integrated over-voltage protection (25V nominal trip), under-voltage lockout (2.4V on-threshold), internal soft-start, and analog dimming via 0.2–3.5V Cntrl pin voltage that linearly scales feedback reference from 0.5V to 0.6V - enabling precise LED current regulation without external DACs or filters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 5.5V - supports single-cell Li-ion and regulated 3.3V/5V rails without external LDO. |
| OVP Threshold | 22.5V to 25.5V - protects against open-circuit LED failure in 25V-rated version; enables use of low-profile ceramic output capacitors. |
| Peak Switch Current | 400–600 mA - sets maximum drive capability for 2–5 white LEDs per segment at typical forward voltages. |
| Switching Frequency | 0.8–1.2 MHz - allows compact external inductor (e.g., 2.2 µH) and minimizes EMI with fixed-frequency operation. |
| Feedback Reference | 0.5–0.6 V - defines LED current via external sense resistor; scaled linearly by Cntrl pin voltage for analog dimming. |
| Efficiency | Up to 80% - measured at 4.2V input, 15mA LED current, and 8-LED configuration; peaks near mid-load range. |
| Thermal Resistance θJA | 49°C/W (WQFN) - requires minimal PCB copper area for thermal management in space-constrained handheld designs. |
Pinout & Package
LM3503ITL-25/NOPB uses a 16-pin WQFN package (RGH0016A) with 3.0 mm × 3.0 mm footprint and 0.4 mm pitch. The exposed die attach pad (DAP) must be soldered to PCB ground plane for thermal dissipation and EMI reduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input power supply connection | Accepts 2.5–5.5V; requires local 4.7 µF ceramic capacitor placed adjacent to pin to suppress high-frequency ripple. |
| Sw | Drain of internal NMOS power switch (N1) | Connects to inductor; trace must be short/wide to minimize EMI and resistive loss during 1 MHz switching. |
| En1 | PMOS FET (P1) enable control for MAIN display | Logic-high (≥1.4V) disables MAIN segment; internal pull-down ensures default OFF state when floating. |
| En2 | NMOS FET (N2) enable control for SUB display | Logic-high (≥1.4V) disables SUB segment; must be grounded if VOUT2 unused to prevent undefined operation. |
| Fb | Feedback node for current-sense amplifier | Monitors voltage across external sense resistor; regulates LED current to maintain 0.5–0.6V at this pin. |
| Cntrl | Analog dimming control input | 0.2–3.5V DC input linearly adjusts feedback reference; no RC filtering needed for basic analog dimming. |
| AGND | Analog ground reference | Must be tied directly to PGND at single point to avoid noise coupling into feedback path. |
| PGND | Power ground return | High-current return path for Sw, VOUT1, VOUT2; connects to PCB ground plane under DAP for thermal conduction. |
| VOUT1 | OVP sensing node & PMOS source (P1) | Connects to cathode of main LED string; OVP comparator monitors this pin to halt switching if >25.5V detected. |
| VOUT2 | Drain of internal NMOS/PMOS switches (N2/P1) | Midpoint between MAIN and SUB segments; requires 100 nF capacitor to ground if unused to stabilize switching node. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent display control | En1/En2 pins enable hardware-selectable MAIN/SUB segment activation without software or external logic. |
| Analog brightness control | Cntrl pin accepts 0.2–3.5V DC to scale LED current linearly - eliminates need for PWM generation or DAC in simple UIs. |
| Integrated OVP with 25V threshold | Prevents damage during LED open-circuit faults; eliminates requirement for external Zener clamp diodes. |
| 1 MHz fixed-frequency PWM | Enables use of small, low-DCR inductors (e.g., DO1608C-223) and reduces audible noise compared to variable-frequency PFM schemes. |
| Internal soft-start | Gradually ramps current limit at startup to eliminate inrush current spikes that could destabilize battery-powered systems. |
Applications
| Cellular Phone Main/Sub Display | PDA Dual-Screen Backlight |
|---|---|
Use Scenario: Simultaneous illumination of primary LCD and secondary status OLED in clamshell phones. IC Role / Device Role / Timing Role: Constant-current driver managing two independent LED strings from single inductor topology. Use Value: Reduces BOM count by eliminating second boost converter; En1/En2 allow instant segment switching during call/screen transitions. | Use Scenario: Powering front-panel main display and rear-panel touch-sensitive keypad backlight in enterprise PDAs. IC Role / Device Role / Timing Role: Dual-channel LED current regulator with hardware-enabling logic for context-aware lighting. Use Value: Enables adaptive brightness where MAIN display runs at full intensity while SUB dims to conserve battery during idle states. |
| Portable Media Player UI Lighting | Handheld Barcode Scanner Display |
Use Scenario: Illuminating color TFT main screen and monochrome secondary info panel in MP4 players. IC Role / Device Role / Timing Role: Analog-dimming-capable dual-output LED driver synchronized to UI refresh rate. Use Value: Cntrl pin enables smooth fade transitions between menus without microcontroller PWM overhead or flicker artifacts. | Use Scenario: Driving both the scanner's aiming laser indicator and its status LED array in industrial-grade handheld scanners. IC Role / Device Role / Timing Role: Dual-current-source driver supporting different LED counts and forward voltages per channel. Use Value: VOUT1/VOUT2 architecture allows separate optimization - e.g., 4 LEDs on MAIN (VOUT1–VOUT2), 2 on SUB (VOUT2–Fb) - maximizing efficiency per segment. |
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 |
|---|---|---|---|
| LM3503ITL-16/NOPB | 16V OVP threshold; lower peak switch current (250–400 mA); identical pinout and control interface. | Suitable only for ≤4 white LEDs per segment due to reduced OVP headroom and current limit. | Select when driving shorter LED strings (<4 LEDs) and tighter board space constraints justify lower protection margin. |
| LM3503ITL-44/NOPB | 44V OVP threshold; same 400–600 mA peak current; identical pinout and control interface. | Supports longer LED strings (up to 10 LEDs total) and higher forward voltage drops in harsh ambient conditions. | Choose for ruggedized portable devices requiring extended OVP margin against transient overvoltage or LED aging effects. |
Compared with LM3503ITL-16/NOPB and LM3503ITL-44/NOPB, the LM3503ITL-25/NOPB offers balanced OVP headroom for mainstream 2–5 LED per segment configurations, delivering optimal trade-off between protection robustness, thermal performance, and bill-of-materials cost in consumer handheld designs.
Availability
LM3503ITL-25/NOPB is available at Aetrix Electronics and suitable for cellular phone backlighting, PDA dual-screen systems, and portable media player UI lighting requiring stable component supply and long-term production continuity.
Supply support for LM3503ITL-25/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 LED driver innovation.
The LM3503 product line was engineered specifically for dual-display portable electronics, integrating segmented enable logic, analog dimming, and robust protection to simplify backlight subsystem design in space- and power-constrained devices.
FAQ
What is the exact over-voltage protection threshold for LM3503ITL-25/NOPB?
The LM3503ITL-25/NOPB has a guaranteed OVP on-threshold of 22.5V to 25.5V and off-threshold of 21.5V to 24.5V, as specified in the Electrical Characteristics table. This 25V nominal rating is factory-trimmed and applies across −40°C to +125°C junction temperature range without external components.
Can LM3503ITL-25/NOPB drive 8 white LEDs total across both displays?
Yes, LM3503ITL-25/NOPB can drive up to 8 white LEDs - for example, 5 on MAIN (VOUT1–VOUT2) and 3 on SUB (VOUT2–Fb) - provided total forward voltage remains below 25V and peak current stays within 400–600 mA limits. Efficiency drops above 6 LEDs but remains functional per datasheet Figure 11.
How does the Cntrl pin voltage translate to actual LED current in LM3503ITL-25/NOPB?
In LM3503ITL-25/NOPB, Cntrl pin voltage (0.2–3.5V) linearly scales the internal feedback reference from 0.5V to 0.6V. LED current equals VFb / RSENSE, so a 1.6V Cntrl input yields ~0.55V at Fb, setting ILED = 0.55V / RSENSE - enabling precise analog dimming without lookup tables or calibration.
Is LM3503ITL-25/NOPB pin-compatible with other LM3503 variants like LM3503ITL-44/NOPB?
Yes, LM3503ITL-25/NOPB shares identical 16-pin WQFN (RGH0016A) package, pinout, and control interface with LM3503ITL-16/NOPB and LM3503ITL-44/NOPB - allowing direct substitution in layout when OVP rating and current limits align with system requirements.
What thermal derating applies to LM3503ITL-25/NOPB at 85°C ambient?
At TA = 85°C, LM3503ITL-25/NOPB's maximum allowable power dissipation is 1.33 W, calculated using θJA = 49°C/W and TJ(MAX) = 150°C. This supports continuous 600 mA switching at moderate duty cycles; thermal shutdown activates if junction exceeds 150°C.
LM3503ITL-25/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:
- 25V
- Current - Output / Channel:
- 600mA (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)
LM3503ITL-25/NOPB FAQ
1.How can I place an order for LM3503ITL-25/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3503ITL-25/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 LM3503ITL-25/NOPB reliable?
The price and inventory of LM3503ITL-25/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3503ITL-25/NOPB is usually 5 days.
3.What payment methods are accepted for LM3503ITL-25/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3503ITL-25/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3503ITL-25/NOPB?
LM3503ITL-25/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3503ITL-25/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 LM3503ITL-25/NOPB?
For technical support, including LM3503ITL-25/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3503ITL-25/NOPB requirements.
6.How does Aetrix verify that LM3503ITL-25/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3503ITL-25/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 LM3503ITL-25/NOPB meets industry standards.
7.What is the process for return or replacement of LM3503ITL-25/NOPB?
All LM3503ITL-25/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3503ITL-25/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 LM3503ITL-25/NOPB part is unused and in its original packaging.
Return procedure for LM3503ITL-25/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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