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Texas Instruments LM3519MK-20
- Part No.:
- LM3519MK-20
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LM3519MK-20.pdf
- Description:
- IC LED DRVR RGLTR PWM TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:4,925
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Product details
Overview
LM3519MK-20 from Texas Instruments is a high-frequency boost white LED driver IC optimized for LCD backlighting in mobile phones and handheld devices. It delivers constant 20mA current to 2–4 series-connected white LEDs, operates with 2.7V–5.5V input, features proprietary PFM regulation (2–8MHz switching), and supports up to 30kHz PWM brightness control via the EN pin.
For engineers reviewing the LM3519MK-20 datasheet, LM3519MK-20 pinout, LM3519MK-20 application, or LM3519MK-20 equivalent, this page provides verified technical context, real-world design implications of its PFM architecture, confirmed SOT-23-6 package mapping, and validated alternatives for LED backlighting power stage selection.
Technical Context
The LM3519MK-20 implements a non-pulse-skipping variable-frequency PFM control architecture that forces operation at the edge of continuous conduction mode (CCM), dynamically adjusting on-time to regulate LED current based on feedback from the LED_rtn pin. Its internal 20mA current reference and error amplifier maintain tight output current accuracy across input voltage and temperature variations.
Switching frequency scales inversely with inductor value: 4–8MHz with 1µH, 2–5MHz with 2.2µH, and 2–4MHz with 3.3µH. Over-voltage protection triggers at 17.8–20V, and true shutdown isolation disconnects VOUT from VIN to eliminate LED leakage current paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LED drive current | 20mA (internally trimmed, ±10% tolerance over full operating range) |
| Input voltage range | 2.7V to 5.5V (supports single-cell Li-ion and Li-poly battery operation) |
| Switching frequency | 2MHz to 8MHz (enables use of ultra-small 1–3.3µH inductors and low-ESR ceramic capacitors) |
| PWM dimming range | Up to 30kHz (avoids audible noise and visible flicker; linearity degrades above 30kHz) |
| Peak efficiency | >80% (achieved with 2.2µH inductor and 4 LEDs at VIN = 3.6V) |
| Over-voltage protection | 17.8–20V threshold (protects LEDs and external diode against output overvoltage faults) |
| Shutdown isolation | True output disconnect (eliminates reverse current path through LEDs during disable) |
Pinout & Package
LM3519MK-20 is housed in a 6-pin SOT-23-THIN (DDC) package with 1.1mm max height, RoHS-compliant Sn lead finish, and MSL Level-1 rating. The package footprint matches JEDEC MO-193 and requires Q3 pin-1 quadrant orientation on tape-and-reel.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - En | Enable logic input | Active-high digital control; 0.3V/0.9V thresholds enable precise PWM dimming without external level-shifting |
| 2 - Gnd | Power ground reference | Common return for internal switch, error amplifier, and bias circuitry; must be low-impedance connection |
| 3 - VOUT | Boost output node | Connects to anode of external flyback diode and cathode of output capacitor; withstands up to +21V |
| 4 - LED_rtn | LED current sense input | Senses voltage drop across internal NMOS switch (RDS(ON) = 8Ω) to regulate LED current at 20mA |
| 5 - SW | Internal power FET drain | Switching node connected to inductor; handles peak currents up to 750mA and voltage swings up to +21V |
| 6 - VIN | Input supply connection | Accepts 2.7–5.5V; internal 550–900µA quiescent current during switching ensures low standby loss |
Key Features
| Feature | Design Value |
|---|---|
| Proprietary PFM regulation | Enables 2–8MHz variable-frequency operation without pulse skipping, minimizing EMI and enabling tiny passive components |
| Integrated 20mA current reference | Eliminates external current-setting resistors and ensures matched LED brightness across strings without trimming |
| True shutdown isolation | Internally disconnects VOUT from VIN during disable, preventing LED leakage current and extending battery life |
| Over-voltage protection (OVP) | Hardware-based clamping at 17.8–20V prevents damage to LEDs and external diode under open-circuit or fault conditions |
| Small external component count | Requires only one inductor (1–3.3µH), one input cap (4.7µF), one output cap (1µF), and one Schottky diode |
Applications
| Mobile Phone LCD Backlighting | Digital Still Camera Backlighting |
|---|---|
|
Use Scenario: Driving 4-series white LEDs for main display backlight in compact smartphones with single-cell Li-ion battery (3.0–4.2V). IC Role / Device Role / Timing Role: Boost converter controller with integrated current regulation and PWM-enabled brightness control. Use Value: Delivers stable 20mA per LED across battery discharge curve while maintaining >80% efficiency and eliminating need for external current-sense resistors. |
Use Scenario: Powering dual white LED strings for rear LCD viewfinder backlight in DSLR and mirrorless cameras. IC Role / Device Role / Timing Role: High-frequency DC-DC boost driver with fast transient response for on-demand flash-assisted preview illumination. Use Value: Enables flicker-free 30kHz PWM dimming synchronized with image capture timing, reducing visual artifacts during live view. |
| PDA Display Illumination | Handheld Medical Device Indicator |
|
Use Scenario: Providing uniform backlight for monochrome or color TFT displays in legacy PDAs with 3.3V regulated rail. IC Role / Device Role / Timing Role: Constant-current LED driver with true shutdown to meet strict standby current budgets (<0.1µA). Use Value: Achieves <100nA shutdown current and eliminates LED glow during sleep mode, extending device runtime between charges. |
Use Scenario: Driving status indicator LEDs in portable diagnostic tools requiring reliable, low-noise illumination under battery power. IC Role / Device Role / Timing Role: Low-EMI boost driver with OVP and thermal robustness for safety-critical visual feedback circuits. Use Value: Prevents LED overvoltage failure during hot-swap events and maintains ±5.5% current accuracy from −40°C to +85°C ambient. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED boost driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3509MK-20/NOPB | Same SOT-23-6 package and 20mA current setting, but uses fixed-frequency PWM (1.2MHz) instead of PFM; lower peak efficiency (~75%) and higher EMI. | Preferred where deterministic switching frequency simplifies EMI filtering; less suitable for ultra-low-noise or battery-sensitive designs. | Select LM3509MK-20/NOPB when system-level EMI testing requires predictable fundamental frequency rather than broadband PFM noise. |
| TPS61160DRVR | Higher 40mA drive capability, 1.2MHz fixed-frequency operation, and integrated Schottky diode; no true shutdown isolation. | Used in higher-brightness applications (e.g., tablet backlights); lacks LED_rtn sensing and requires external current programming. | Choose TPS61160DRVR when driving >4 LEDs or needing integrated diode to reduce BOM count, accepting trade-offs in efficiency and shutdown leakage. |
Compared with LM3519MK-20, LM3509MK-20/NOPB offers predictable EMI but sacrifices efficiency and noise performance, while TPS61160DRVR increases drive capability and integration at the cost of current accuracy and true shutdown functionality-making LM3519MK-20 optimal for space-constrained, battery-powered 2–4 LED backlighting where efficiency, low noise, and zero leakage are critical.
Availability
LM3519MK-20 is available at Aetrix Electronics and suitable for mobile phone backlighting, digital camera illumination, and handheld medical device indicators requiring stable component supply across extended production lifecycles.
Supply support for LM3519MK-20 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 expertise in precision power conversion and LED lighting solutions.
The LM3519MK-20 belongs to TI's white LED backlight driver product line, designed specifically for high-efficiency, low-noise, and ultra-compact boost conversion in battery-powered portable displays.
FAQ
What is the exact LED current accuracy specification for LM3519MK-20?
The LM3519MK-20 guarantees LED current tolerance of ±10% over the full operating junction temperature range (−40°C to +125°C) and input voltage range (2.7V to 5.5V), with typical variation of ±5.5% at TJ = +25°C. This accuracy is achieved using an internal trimmed current reference and feedback via the LED_rtn pin, eliminating dependence on external resistor tolerances. The LM3519MK-20 maintains this specification without calibration or trimming in production systems.
Does LM3519MK-20 support driving only two LEDs, and what design adjustments are required?
Yes, LM3519MK-20 supports driving two white LEDs, but requires a minimum inductance of 2.2µH to maintain loop stability and current accuracy. Using a smaller inductor (e.g., 1µH) causes increased LED current variation with input voltage due to degraded regulation. The LM3519MK-20 datasheet confirms that 2.2µH is mandatory for 2-LED operation, whereas 4-LED configurations allow flexibility down to 1µH. Layout and capacitor selection remain unchanged.
What is the maximum recommended PWM dimming frequency for LM3519MK-20, and why is there an upper limit?
The LM3519MK-20 supports PWM dimming up to 30kHz, beyond which LED current linearity versus duty cycle degrades. This limit arises from internal timing constraints in the PFM control loop and gate-drive propagation delays. Operation above 30kHz may cause inconsistent current regulation during short on-pulses, leading to brightness nonlinearity and reduced dimming resolution. For optimal performance, TI specifies 17–30kHz as the recommended range to avoid both audible noise and current inaccuracies.
How does the LM3519MK-20 achieve >80% peak efficiency, and what component values deliver this result?
The LM3519MK-20 achieves >80% peak efficiency using its high-frequency PFM architecture (2–8MHz), which minimizes core losses in small inductors and reduces conduction losses via low RDS(ON) internal switches (455mΩ for power FET, 8Ω for LED_rtn NMOS). Peak efficiency is measured at VIN = 3.6V, driving 4 LEDs with a 2.2µH inductor, 4.7µF input capacitor, and 1µF output capacitor. Efficiency drops to ~75% with 1µH inductors due to higher switching losses.
Is LM3519MK-20 pin-compatible with other members of the LM35xx family, such as LM3517 or LM3520?
No, LM3519MK-20 is not pin-compatible with LM3517 or LM3520. While all three belong to TI's white LED driver family and use SOT-23-6 packages, their pin functions differ significantly: LM3517 uses FB for external current setting, LM3520 has separate DIM and EN pins, and LM3519MK-20 integrates current regulation and uses LED_rtn for sensing. Substituting any of these requires PCB layout changes and firmware updates to match signal routing and control logic.
LM3519MK-20 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SOT-23-6 Thin, TSOT-23-6
- 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):
- 5.5V
- Voltage - Output:
- 20V
- Current - Output / Channel:
- 20mA
- Frequency:
- 5.4MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-6
LM3519MK-20 FAQ
1.How can I place an order for LM3519MK-20 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3519MK-20 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 LM3519MK-20 reliable?
The price and inventory of LM3519MK-20 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3519MK-20 is usually 5 days.
3.What payment methods are accepted for LM3519MK-20?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3519MK-20 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3519MK-20?
LM3519MK-20 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3519MK-20 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 LM3519MK-20?
For technical support, including LM3519MK-20 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3519MK-20 requirements.
6.How does Aetrix verify that LM3519MK-20 is sourced from the original manufacturer or authorized distributors?
All LM3519MK-20 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 LM3519MK-20 meets industry standards.
7.What is the process for return or replacement of LM3519MK-20?
All LM3519MK-20 units undergo pre-shipment inspection (PSI). If there is an issue with LM3519MK-20, 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 LM3519MK-20 part is unused and in its original packaging.
Return procedure for LM3519MK-20:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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