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Texas Instruments LM3503ITL-44/NOPB
- Part No.:
- LM3503ITL-44/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 10-WFBGA, DSBGA
- Datasheet:
-
LM3503ITL-44/NOPB.pdf
- Description:
- IC LED DRIVER RGLTR DIM 10DSBGA
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM3503ITL-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 segment). It operates from 2.5 V to 5.5 V input and delivers precise current regulation in portable backlighting systems.
For engineers reviewing the LM3503ITL-44/NOPB datasheet, LM3503ITL-44/NOPB pinout, LM3503ITL-44/NOPB application, or LM3503ITL-44/NOPB equivalent, this page provides verified functional specifications, validated pin roles, confirmed dual-string control logic, real-world efficiency curves, and manufacturer-confirmed alternative options for portable display power design.
Technical Context
The LM3503ITL-44/NOPB implements an asynchronous current-mode PWM controller with integrated NMOS/PMOS FET switches, enabling independent MAIN and SUB white LED string control via En1 and En2 pins. Its feedback loop regulates LED current using a voltage-controlled Cntrl pin that sets the internal reference for the error amplifier.
It features cycle-by-cycle current limiting, thermal shutdown, input under-voltage protection (2.4 V turn-on), and output over-voltage protection at 44 V (±1.5 V threshold tolerance). The device supports both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) operation, with maximum duty cycle limited to 95%.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output OVP Threshold | 44 V nominal; disables switching if VOUT1 exceeds 42–43.5 V to protect LEDs and external diode/capacitor |
| Input Voltage Range | 2.5 V to 5.5 V; compatible with single-cell Li-ion (3.0–4.2 V) and dual-cell alkaline (2.4–3.2 V) supplies |
| Switching Frequency | 1 MHz ±20%; enables compact magnetics (e.g., 2.2 µH inductor) and reduces EMI filtering burden |
| LED Current Control | Analog via 0.2–3.5 V on Cntrl pin; maps linearly to feedback voltage (VFb = 0.156 × VCntrl) for stable dimming |
| Peak Efficiency | >80% at 15 mA per string with VIN = 3.6 V; achieved via low RDS(ON) NMOS (0.55 Ω typ) and optimized gate drive |
| Junction Temp Range | −40°C to +125°C; supports industrial-grade portable devices with extended ambient operating conditions |
| Package Thermal Resistance | 65°C/W (θJA, DSBGA); requires PCB ground plane connection via DAP for reliable 1.9 mA switching quiescent current |
Pinout & Package
LM3503ITL-44/NOPB uses a 10-bump thin DSBGA package (YPA0010), height <1 mm, with die attach pad (DAP) soldered to PCB ground for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input supply connection | Accepts 2.5–5.5 V; requires local 4.7 µF ceramic capacitor between VIN and PGND to suppress high-frequency ripple |
| Sw | Power NMOS drain node | Connects to inductor; high dv/dt node requiring short, wide trace routing to minimize EMI and switching losses |
| En1 | MAIN display enable control | Logic-high (≥1.4 V) disables PMOS switch P1, turning ON MAIN LED string; internal pull-down holds default OFF state |
| En2 | SUB display enable control | Logic-high (≥1.4 V) disables NMOS switch N2, turning ON SUB LED string; floating or grounded when unused |
| Fb | Feedback voltage sensing | Monitors regulated output current via resistor divider; VFb = 0.55 V typical; used with Cntrl pin for analog dimming |
| Cntrl | Analog brightness control input | 0.2–3.5 V DC input; directly scales VFb reference (VFb = 0.156 × VCntrl); bias current ≤14 µA ensures low-power dimming |
| AGND | Analog ground reference | Must be tied directly to PGND near device; separates noise-sensitive feedback path from high-current power return |
| PGND | Power ground return | High-current return for Sw, VOUT1, VOUT2; connects to PCB ground plane and DAP for thermal dissipation |
| VOUT1 | OVP sense & PMOS source | OVP detection node for MAIN string; connects to Schottky diode anode and output capacitor cathode |
| VOUT2 | NMOS/PMOS drain junction | Interconnect point between MAIN and SUB strings; 100 nF capacitor required if unused to stabilize OVP comparator |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent LED string control | Separate En1/En2 logic enables MAIN/SUB display activation without external MOSFETs or sequencing circuitry |
| Integrated OVP at 44 V | Prevents damage during open-circuit LED failure or disconnection; eliminates need for external Zener clamp |
| 1 MHz fixed-frequency PWM | Reduces inductor size by >50% vs. 500 kHz drivers; improves transient response and simplifies EMI filter design |
| Internal soft-start | Gradually ramps current limit at startup to avoid inrush into output capacitor and LED string |
| Thermal shutdown protection | Disables switching above +150°C junction temperature; auto-recovery after cooldown prevents system lockup |
| Low-profile DSBGA package | 0.8 mm max height enables ultra-thin handheld designs; DAP-to-PCB soldering improves thermal performance by 30% |
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 regulating two independent LED strings with dynamic brightness scaling via analog Cntrl voltage. Use Value: Enables seamless transition between displays without flicker or current mismatch; 44 V OVP protects against LED open-circuit faults during hinge flexing. |
Use Scenario: Powering front-panel main LCD and rear-panel battery/status indicator on enterprise PDAs. IC Role / Device Role / Timing Role: Dual-channel current source with independent En1/En2 enable logic for selective display activation. Use Value: Eliminates need for discrete enable logic or dual-driver ICs; reduces BOM count by 3 components per unit. |
| Portable Media Player UI Lighting | Handheld Barcode Scanner Display |
Use Scenario: Backlighting touch-sensitive menu interface and secondary battery-level indicator in MP3/video players. IC Role / Device Role / Timing Role: Analog-dimming LED driver supporting smooth brightness ramping via DAC-controlled Cntrl pin. Use Value: Achieves 100:1 dimming range with <1% current variation across 0.2–3.5 V Cntrl input; no PWM filtering required. |
Use Scenario: Illuminating small LCD screen and LED aiming guide in rugged industrial barcode scanners. IC Role / Device Role / Timing Role: High-efficiency boost driver with UVP (2.4 V) and thermal shutdown for battery-operated field use. Use Value: Maintains consistent brightness down to 2.5 V battery voltage; 80% peak efficiency extends runtime by 12% vs. linear drivers. |
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-25/NOPB | 25 V OVP threshold; lower RDS(ON) PMOS (5 Ω vs. 10 Ω) but same 44 V version's higher OVP headroom | Suitable only for ≤25 V LED stacks; cannot replace LM3503ITL-44/NOPB in 35–44 V fault-tolerant designs | Select only when system OVP margin requirement is ≤25 V and cost sensitivity outweighs safety margin needs |
| TPS61165DRVR | Single-output, 40 V OVP, I²C programmable current; lacks dual-string En1/En2 logic and analog Cntrl pin | Requires external logic or MCU firmware to emulate dual-display control; no native analog dimming interface | Choose when digital control and programmability are prioritized over analog simplicity and dual-enable hardware logic |
Compared with LM3503ITL-25/NOPB and TPS61165DRVR, the LM3503ITL-44/NOPB uniquely combines 44 V OVP headroom, hardware-based dual-string enable control, and direct analog dimming-enabling robust, low-component-count backlighting for safety-critical portable displays.
Availability
LM3503ITL-44/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, long-term lifecycle support, and guaranteed RoHS-compliant packaging.
Supply support for LM3503ITL-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 ICs, with decades of expertise in portable power solutions and LED driver innovation.
The LM3503 product line was designed specifically for dual-display backlighting in space-constrained portable electronics, integrating dual-string control, analog dimming, and robust protection in sub-1 mm packages.
FAQ
What is the over-voltage protection threshold for LM3503ITL-44/NOPB?
The LM3503ITL-44/NOPB has a nominal over-voltage protection threshold of 44 V, with an on-threshold range of 40.5–43.5 V and off-threshold of 39.0–42.0 V. This OVP function monitors the VOUT1 pin and disables switching if the output exceeds the threshold, protecting external LEDs, diodes, and capacitors from overvoltage stress during open-circuit failures. The LM3503ITL-44/NOPB is specifically rated for this 44 V level, distinguishing it from other variants like the -16 or -25 versions.
How does analog brightness control work on LM3503ITL-44/NOPB?
Analog brightness control on LM3503ITL-44/NOPB is implemented via the Cntrl pin, which accepts a DC voltage from 0.2 V to 3.5 V. This voltage linearly scales the internal feedback reference: VFb = 0.156 × VCntrl. Since LED current is regulated to maintain VFb at ~0.55 V, varying VCntrl directly adjusts target current. The LM3503ITL-44/NOPB achieves smooth dimming without PWM filtering, supporting full-range control with <1% current deviation across temperature and input voltage.
Can LM3503ITL-44/NOPB drive both MAIN and SUB displays simultaneously?
Yes, LM3503ITL-44/NOPB can drive both MAIN and SUB displays simultaneously by setting En1 ≥1.4 V and En2 ≥1.4 V. In this configuration, the PMOS switch (P1) and NMOS switch (N2) are both disabled, allowing current to flow through the full LED string from VOUT1 to Fb via VOUT2. The LM3503ITL-44/NOPB's internal architecture supports this mode explicitly, and the datasheet confirms identical current-limit behavior (450–1050 mA) whether driving 4, 6, 8, or 10 LEDs total.
What package type does LM3503ITL-44/NOPB use, and how is thermal management handled?
LM3503ITL-44/NOPB uses a 10-bump thin DSBGA package (YPA0010), measuring 1.6 mm × 2.1 mm with <1 mm height. Thermal management relies on soldering the exposed die attach pad (DAP) directly to the PCB's ground plane, which serves as the primary heat path. With θJA = 65°C/W, this construction enables reliable operation at up to 1.9 mA switching quiescent current and full-load conditions in handheld enclosures without added heatsinking.
Is LM3503ITL-44/NOPB pin-compatible with other LM3503 variants?
No, LM3503ITL-44/NOPB is not pin-compatible with other LM3503 variants due to differing internal OVP thresholds and associated internal resistor networks - though all share the same 10-bump DSBGA footprint and pinout assignment. The LM3503ITL-44/NOPB's VOUT1 OVP comparator is factory-trimmed for 44 V, while LM3503ITL-25/NOPB is trimmed for 25 V; swapping them risks incorrect fault response or premature shutdown. Board layout must match the specific variant's OVP rating.
LM3503ITL-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)
LM3503ITL-44/NOPB FAQ
1.How can I place an order for LM3503ITL-44/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3503ITL-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 LM3503ITL-44/NOPB reliable?
The price and inventory of LM3503ITL-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 LM3503ITL-44/NOPB is usually 5 days.
3.What payment methods are accepted for LM3503ITL-44/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3503ITL-44/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3503ITL-44/NOPB?
LM3503ITL-44/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3503ITL-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 LM3503ITL-44/NOPB?
For technical support, including LM3503ITL-44/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3503ITL-44/NOPB requirements.
6.How does Aetrix verify that LM3503ITL-44/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3503ITL-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 LM3503ITL-44/NOPB meets industry standards.
7.What is the process for return or replacement of LM3503ITL-44/NOPB?
All LM3503ITL-44/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3503ITL-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 LM3503ITL-44/NOPB part is unused and in its original packaging.
Return procedure for LM3503ITL-44/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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