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Texas Instruments LM3500TL-21/NOPB
- Part No.:
- LM3500TL-21/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 8-WFBGA
- Datasheet:
-
LM3500TL-21/NOPB.pdf
- Description:
- IC LED DRIVER RGLTR 640MA 8DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:1,950
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Product details
Overview
LM3500TL-21/NOPB from Texas Instruments is a synchronous step-up DC/DC converter optimized for white LED backlighting, featuring 20.5 V internal overvoltage protection (OVP), 1 MHz fixed switching frequency, and 2.7 V to 7 V input range. It drives 4–5 series white LEDs with 0.5 V feedback voltage and supports PWM dimming via the SHDN pin.
For engineers reviewing the LM3500TL-21/NOPB datasheet, LM3500TL-21/NOPB pinout, LM3500TL-21/NOPB application, or LM3500TL-21/NOPB equivalent, this device is selected for compact, high-efficiency LED bias in portable displays where ceramic capacitor compatibility, thermal shutdown, and true shutdown isolation are critical design requirements.
Technical Context
The LM3500TL-21/NOPB implements current-mode PWM control with integrated NMOS/PMOS synchronous rectification-eliminating external Schottky diodes. Its internal OVP comparator clamps output at 20.5 V (typ.) with 1 V hysteresis, enabling use of 25 V ceramic capacitors.
Operation relies on a 0.5 V feedback reference, duty-cycle-limited switching (max 94%), and shutdown logic that disconnects VIN from VOUT with ≤0.1 µA quiescent current. Thermal shutdown activates at ~150°C with ~35°C hysteresis, and undervoltage lockout engages below 2.4 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output OVP Threshold | 20.5 V (typ.) - prevents destructive overvoltage if LED string opens; enables 25 V ceramic COUT selection |
| Feedback Voltage (VFB) | 0.5 V (±0.03 V) - sets LED current via external resistor; low value minimizes power loss in current-sense network |
| Switching Frequency | 1.0 MHz (±15%) - allows small inductors (e.g., 22 µH) and reduces EMI filtering burden |
| Input Voltage Range | 2.7 V to 7.0 V - supports single-cell Li-ion (3.0–4.2 V) and 3-cell NiMH (3.6–4.5 V) battery inputs |
| Shutdown Current | 0.1 µA (max) - ensures negligible battery drain during display-off states in handheld devices |
| Current Limit (Typ) | 670 mA (LM3500-21, VIN = 3.0 V) - defines maximum peak inductor current; constrains max LED string power |
| UVP Threshold | 2.4 V (ON), 2.3 V (OFF) - prevents operation under depleted battery conditions that could cause unstable regulation |
Pinout & Package
LM3500TL-21/NOPB uses an 8-bump thin DSBGA package (1.5 mm × 1.5 mm, 0.5 mm pitch) with exposed thermal pad. Pin layout follows JEDEC MO-220 standard; mechanical drawings confirm bump positions A1–C3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 | AGND | Analog ground reference; must be tied directly to power GND to minimize feedback noise coupling |
| B1 | VIN | Main power input (2.7–7 V); requires local 1 µF ceramic bypass between VIN and GND |
| C1 | VOUT | PMOS source output; connects to cathode of LED string and COUT anode |
| C2 | VSW | Switch node (NMOS drain / PMOS drain); connects to inductor and must be routed short to limit EMI |
| C3 | GND | Power ground; primary return path for inductor current and output capacitor discharge |
| B3 | FB | Feedback input; sets LED current via resistor to GND (ILED = 0.5 V / RLED) |
| A3 | NC | No internal connection; voltage must not exceed 7.5 V; leave unconnected or grounded per layout best practice |
| A2 | SHDN | Active-high shutdown control; <0.3 V disables, >1.1 V enables; accepts PWM for LED dimming |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated NMOS/PMOS switches eliminate external Schottky diode, improving efficiency by ~5–10% vs. asynchronous designs |
| True shutdown isolation | Complete VIN-to-VOUT disconnection in shutdown mode prevents LED leakage current and preserves battery life |
| Internal OVP circuitry | 20.5 V clamp with hysteresis avoids need for external Zener; enables robust open-LED fault handling without board-level redesign |
| Ceramic capacitor support | Stable operation with 1 µF X7R/X5R ceramic CIN and COUT reduces solution size and cost versus tantalum or electrolytic alternatives |
| PWM dimming interface | Direct SHDN-pin PWM control (100 Hz–1 kHz) enables precise brightness adjustment without external MOSFET drivers or analog DACs |
Applications
| Smartphone LCD Backlight | Digital Camera Display |
|---|---|
|
Use Scenario: Driving 4-series white LEDs in a 3.7 V Li-ion powered smartphone display with space-constrained PCB layout. IC Role / Device Role / Timing Role: Step-up converter providing regulated current to LED string; operates at 1 MHz to minimize inductor footprint. Use Value: Synchronous architecture achieves >85% efficiency at 20 mA per LED, extending battery runtime while enabling 1.5 mm × 1.5 mm DSBGA placement near display flex connector. |
Use Scenario: Powering 5-series white LEDs in a compact digital camera rear LCD with variable brightness control. IC Role / Device Role / Timing Role: Constant-current LED driver with PWM-dimmable shutdown; uses internal 20.5 V OVP to survive accidental LED string disconnect during lens actuation. Use Value: 0.1 µA shutdown current prevents standby drain; 0.5 V feedback reference allows accurate current setting with 1% resistors, ensuring consistent display luminance across temperature. |
| Portable Media Player UI | Handheld Barcode Scanner |
|
Use Scenario: Illuminating a 3.5-inch TFT display in a battery-operated media player requiring smooth 100:1 dimming range. IC Role / Device Role / Timing Role: High-efficiency boost converter with SHDN-pin PWM interface; leverages 1 MHz switching for minimal EMI in audio-sensitive environment. Use Value: Ceramic capacitor compatibility eliminates audible coil whine; thermal shutdown (150°C) protects against enclosure overheating during extended playback. |
Use Scenario: Backlighting a ruggedized OLED status display in an industrial barcode scanner powered by replaceable AA batteries. IC Role / Device Role / Timing Role: LED current regulator with undervoltage lockout (2.4 V) preventing erratic behavior as alkaline cells deplete. Use Value: 2.7 V minimum input enables full functionality down to end-of-life battery voltage; 8-bump DSBGA withstands mechanical shock better than SOIC or TSSOP packages. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3500TL-16/NOPB | 15.5 V OVP threshold; 87% max duty cycle; lower switch current limit (400 mA typ.) | Optimized for 3–4 LED strings; unsuitable for 5-LED configurations at typical VF | Select when driving ≤4 LEDs from 3.0–3.6 V sources and 16 V output caps are preferred |
| TPS61160DRVR | 2.7–5.5 V input; 28 V OVP; 1.2 MHz switching; integrated soft-start; no DSBGA option | Supports higher LED counts and wider input range; requires larger 6-pin WSON package | Choose for designs needing >5 LEDs, tighter output ripple, or production scalability beyond TI's discontinued LM3500 family |
Compared with LM3500TL-16/NOPB, the LM3500TL-21/NOPB delivers higher output headroom for 5-LED strings but shares identical pinout, feedback scheme, and shutdown behavior; versus TPS61160DRVR, it offers smaller footprint and lower BOM count at the expense of programmability and newer protection features.
Availability
LM3500TL-21/NOPB is available at Aetrix Electronics and suitable for smartphone LCD backlighting, digital camera displays, and portable media player UIs requiring stable component supply across long-lifecycle consumer electronics programs.
Supply support for LM3500TL-21/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 power conversion and LED lighting solutions.
The LM3500 product line was designed specifically for space-constrained, battery-powered white LED backlighting applications-emphasizing high efficiency, minimal external components, and robust fault protection in portable electronics.
FAQ
What is the maximum number of white LEDs the LM3500TL-21/NOPB can drive in series?
The LM3500TL-21/NOPB can reliably drive up to 5 white LEDs in series when each has a forward voltage ≤3.89 V (e.g., typical 3.2–3.6 V at 20 mA). This is determined by its 20.5 V OVP threshold and 0.5 V feedback voltage, satisfying (N × VF) + 0.53 V ≤ 20 V. Driving 6 LEDs requires VF < 3.24 V and is marginal; 7 LEDs exceeds safe margin per TI's published table.
Does the LM3500TL-21/NOPB require external compensation components?
No, the LM3500TL-21/NOPB features internal compensation and operates stably with only external inductor, input/output capacitors, and FB-set resistor. The current-mode PWM architecture and fixed 1 MHz frequency eliminate need for loop compensation networks, reducing bill-of-materials and layout complexity.
How does the SHDN pin enable PWM dimming on the LM3500TL-21/NOPB?
The SHDN pin accepts logic-level PWM signals (100 Hz–1 kHz) to toggle the LM3500TL-21/NOPB between active and true shutdown states. During active periods, LED current is set by the FB resistor; during shutdown, VIN is isolated from VOUT, eliminating leakage. This provides flicker-free dimming without altering current regulation accuracy.
What ceramic capacitor values are recommended for LM3500TL-21/NOPB input and output?
Texas Instruments specifies 1 µF X7R/X5R ceramic capacitors for both CIN (between VIN and GND) and COUT (between VOUT and GND). For demanding startup conditions, a 4.7 µF ceramic may be added in parallel with CIN. A 100 nF ceramic in parallel with CIN further suppresses high-frequency noise.
Is the LM3500TL-21/NOPB pin-compatible with other variants in the LM3500 family?
Yes, all LM3500 variants-including LM3500TL-16/NOPB and LM3500TL-21/NOPB-share identical 8-bump DSBGA package, pinout, and footprint. The only functional differences are OVP threshold (15.5 V vs. 20.5 V), duty-cycle limit (87% vs. 94%), and current limit (400 mA vs. 670 mA typ.), allowing drop-in replacement where output voltage margin permits.
LM3500TL-21/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-WFBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 7V
- Voltage - Output:
- 21V
- Current - Output / Channel:
- 640mA (Switch)
- Frequency:
- 1MHz
- Dimming:
- -
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DSBGA
LM3500TL-21/NOPB FAQ
1.How can I place an order for LM3500TL-21/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3500TL-21/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 LM3500TL-21/NOPB reliable?
The price and inventory of LM3500TL-21/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3500TL-21/NOPB is usually 5 days.
3.What payment methods are accepted for LM3500TL-21/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3500TL-21/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3500TL-21/NOPB?
LM3500TL-21/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3500TL-21/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 LM3500TL-21/NOPB?
For technical support, including LM3500TL-21/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3500TL-21/NOPB requirements.
6.How does Aetrix verify that LM3500TL-21/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3500TL-21/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 LM3500TL-21/NOPB meets industry standards.
7.What is the process for return or replacement of LM3500TL-21/NOPB?
All LM3500TL-21/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3500TL-21/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 LM3500TL-21/NOPB part is unused and in its original packaging.
Return procedure for LM3500TL-21/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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