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Texas Instruments LM3501TL-21/NOPB
- Part No.:
- LM3501TL-21/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 8-WFBGA
- Datasheet:
-
LM3501TL-21/NOPB.pdf
- Description:
- IC LED DRIVER RGLTR 640MA 8DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:1,803
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Product details
Overview
LM3501TL-21/NOPB from Texas Instruments is a synchronous step-up DC/DC converter optimized for white LED backlighting, featuring 20.5 V output overvoltage protection (OVP), 1 MHz fixed switching frequency, and analog/PWM LED current control via CNTRL and SHDN pins. It operates from 2.7 V to 7 V input, delivers up to 5-series-white-LED drive capability, and uses integrated NMOS/PMOS switches with no external Schottky diode required.
For engineers reviewing the LM3501TL-21/NOPB datasheet, LM3501TL-21/NOPB pinout, LM3501TL-21/NOPB application in LCD bias or LED backlighting, or LM3501TL-21/NOPB equivalent for portable lighting power conversion, this device offers verified 0.1 µA shutdown current, internal thermal shutdown, true input-output isolation in shutdown, and ceramic-capacitor–optimized 8-bump DSBGA packaging.
Technical Context
The LM3501TL-21/NOPB implements a synchronous current-mode PWM controller with internal compensation, eliminating external loop components. Its block diagram integrates dedicated UVP (2.5 V threshold), OVP (20.5 V trip), and thermal shutdown (150 °C) comparators with hysteresis, plus duty-cycle limiting (94 % max) to prevent inductor saturation under heavy load.
It supports dual LED current control: analog regulation via CNTRL pin (75–125 mV turn-on threshold, 0.191×VCNTRL → VFB relationship), and PWM dimming via SHDN pin (100 Hz–1 kHz range). The VSW node handles bidirectional switch current, while VOUT serves as PMOS source-enabling efficient synchronous rectification without external diode losses.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output OVP Threshold | 20.5 V typical - prevents destructive overvoltage if LEDs disconnect; enables use of 25 V ceramic output capacitors |
| Switching Frequency | 1.0 MHz ±15 % - enables compact 22 µH inductor and low-EMI operation with minimal output ripple |
| 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 V nominal) battery inputs |
| Shutdown Current | 0.1 µA maximum - ensures negligible battery drain during display-off states in handheld devices |
| Feedback Voltage | 0.515 V typical at full LED current - sets precise LED current via external FB-to-GND resistor (e.g., 22 Ω → 23.4 mA) |
| Current Limit (Typ.) | 670 mA at VIN = 3.0 V - defines maximum peak inductor current; limits power dissipation during short-circuit or startup |
| Thermal Shutdown | 150 °C trip, 115 °C recovery - protects die under sustained high-power operation; requires PCB thermal relief per JEDEC 4-layer test board |
Pinout & Package
LM3501TL-21/NOPB uses an 8-bump thin DSBGA package (1.6 mm × 1.6 mm, 0.5 mm pitch) with bottom-side solder balls. Thermal performance relies on direct GND ball connection to PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 | AGND | Analog ground reference; must tie directly to C3 (GND) to minimize noise coupling into feedback path |
| B1 | VIN | Main power input (2.7–7 V); requires local 1 µF ceramic bypass capacitor between B1 and C3 |
| C1 | VOUT | PMOS source output; connects to cathode of LED string and output capacitor anode |
| C2 | VSW | Switch node (NMOS drain / PMOS drain); connects to inductor; critical for EMI minimization |
| C3 | GND | Power ground; primary thermal and current return path; must connect to solid ground plane |
| B3 | FB | Voltage feedback input; sets LED current via resistor to GND; sensitive to layout parasitics |
| A3 | CNTRL | Analog LED current control (0–2.7 V); 75–125 mV threshold defines on/off transition |
| A2 | SHDN | Active-high shutdown; <0.3 V disables converter with full input-output isolation; >1.1 V enables |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous rectification | Integrated NMOS/PMOS power switches eliminate external Schottky diode, reducing conduction loss and board area |
| True shutdown isolation | 0.1 µA quiescent current and complete VIN–VOUT disconnection prevent LED leakage current in off state |
| Dual dimming interface | CNTRL pin enables analog dimming (DC voltage); SHDN pin accepts PWM (100 Hz–1 kHz) for flicker-free brightness control |
| Internal protection suite | UVP (2.5 V), OVP (20.5 V), thermal shutdown (150 °C), and cycle-by-cycle current limiting ensure robust field operation |
| Ceramic-capacitor optimized | Stable with 1 µF X7R/X5R input/output ceramics - avoids bulkier tantalum or electrolytic capacitors |
Applications
| LCD Bias Supplies | White LED Back-Lighting |
|---|---|
Use Scenario: Powering high-voltage LCD panel bias rails (e.g., AVDD, VGH) from single-cell battery in portable medical displays. IC Role / Device Role / Timing Role: Step-up converter generating stable 18–20 V rail with tight line/load regulation and low output ripple. Use Value: Eliminates need for discrete charge-pump or transformer-based bias generators; reduces bill-of-materials by 4+ components. |
Use Scenario: Driving 4–5 white LEDs in series for smartphone or digital camera LCD backlighting. IC Role / Device Role / Timing Role: Constant-current LED driver with analog/PWM dimming, synchronized to display frame rate. Use Value: Achieves >85 % efficiency at 20 mA per LED string; supports smooth 1000:1 dimming ratio without color shift. |
| Handheld Devices | Digital Cameras |
Use Scenario: Compact backlight solution in barcode scanners or ruggedized PDAs where board space and battery life are constrained. IC Role / Device Role / Timing Role: Primary LED power stage with integrated protection against battery undervoltage and thermal overload. Use Value: Enables 1.6 mm × 1.6 mm footprint and 0.1 µA shutdown current - extends standby time beyond 30 days on 300 mAh battery. |
Use Scenario: Flash-assisted autofocus illumination and rear-panel OLED/LCD backlight in compact digital cameras. IC Role / Device Role / Timing Role: High-efficiency boost converter delivering regulated current to dual LED strings with independent dimming control. Use Value: Supports burst-mode operation up to 500 mA peak current; maintains stable output during rapid zoom/focus motor transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3501TL-16/NOPB | Lower OVP threshold (15.5 V), 87 % max duty cycle, 400 mA typical current limit | Optimized for ≤4-LED strings (e.g., 3.6 V VF × 4 = 14.4 V); unsuitable for 5-LED or high-VF configurations | Select when driving ≤4 LEDs from 3.0–4.2 V supply and board space allows same DSBGA footprint |
| TPS61160DRVR | Higher 28 V OVP, 1.2 MHz switching, integrated soft-start; requires external Schottky diode | Supports up to 6 LEDs; lacks true shutdown isolation (µA leakage persists); larger 6-pin SOT-23 package | Choose for higher output voltage margin or where external diode layout is acceptable; avoid in ultra-low-leakage systems |
Compared with LM3501TL-16/NOPB, the LM3501TL-21/NOPB enables one additional LED in series without redesigning feedback or OVP circuitry; versus TPS61160DRVR, it eliminates diode loss and leakage but trades off OVP headroom and soft-start control.
Availability
LM3501TL-21/NOPB is available at Aetrix Electronics and suitable for LCD bias supplies, white LED back-lighting, handheld devices, digital cameras, and portable applications requiring stable component supply across production lifecycles.
Supply support for LM3501TL-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 portable power conversion and LED driver solutions.
The LM3501 product line was designed specifically for high-efficiency, space-constrained white LED backlighting in battery-powered consumer electronics - emphasizing integration, low quiescent current, and robust protection.
FAQ
What is the maximum number of white LEDs the LM3501TL-21/NOPB can drive in series?
The LM3501TL-21/NOPB can drive up to 5 white LEDs in series when each has a forward voltage ≤3.28 V at 20 mA, based on its 20.5 V OVP threshold and 0.545 V feedback headroom. Driving 6 LEDs requires VF ≤2.78 V - verify LED datasheet VF tolerance across temperature and current before final design.
Does the LM3501TL-21/NOPB require an external Schottky diode?
No, the LM3501TL-21/NOPB does not require an external Schottky diode. It integrates synchronous NMOS and PMOS power switches, enabling efficient rectification during the flyback phase without diode conduction losses or reverse-recovery issues.
How does the CNTRL pin control LED current in the LM3501TL-21/NOPB?
The CNTRL pin sets LED current via a linear relationship: VFB ≈ 0.191 × VCNTRL. With VCNTRL = 2.7 V, VFB ≈ 0.515 V, yielding ILED = 0.515 V / RFB. Current regulation begins above 125 mV; below 75 mV, LEDs turn off completely.
What is the purpose of the SHDN pin on the LM3501TL-21/NOPB besides enabling/disabling?
Beyond enable/disable, the SHDN pin accepts PWM signals (100 Hz–1 kHz) to modulate LED brightness. At 200–500 Hz, it achieves deep dimming down to µA-level currents without visible flicker, leveraging the device's fast startup and true shutdown isolation.
Can the LM3501TL-21/NOPB operate with input voltage below 2.7 V?
No - the LM3501TL-21/NOPB has a 2.4–2.6 V undervoltage lockout (UVP) threshold. Operation below 2.7 V is outside the specified input range; attempting to operate at <2.4 V disables switching, and sustained sub-threshold voltage may cause unstable regulation or increased quiescent current.
LM3501TL-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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DSBGA
LM3501TL-21/NOPB FAQ
1.How can I place an order for LM3501TL-21/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3501TL-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 LM3501TL-21/NOPB reliable?
The price and inventory of LM3501TL-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 LM3501TL-21/NOPB is usually 5 days.
3.What payment methods are accepted for LM3501TL-21/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3501TL-21/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3501TL-21/NOPB?
LM3501TL-21/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3501TL-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 LM3501TL-21/NOPB?
For technical support, including LM3501TL-21/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3501TL-21/NOPB requirements.
6.How does Aetrix verify that LM3501TL-21/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3501TL-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 LM3501TL-21/NOPB meets industry standards.
7.What is the process for return or replacement of LM3501TL-21/NOPB?
All LM3501TL-21/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3501TL-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 LM3501TL-21/NOPB part is unused and in its original packaging.
Return procedure for LM3501TL-21/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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