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Analog Devices Inc. LT3519EMS#PBF
- Part No.:
- LT3519EMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT3519EMS#PBF.pdf
- Description:
- IC LED DRV RGLTR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:325
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Product details
Overview
LT3519EMS#PBF from Analog Devices (formerly Linear Technology) is a fixed-frequency 400kHz step-up DC/DC LED driver IC with integrated 45V/750mA low-side switch and Schottky diode. It supports constant-current and constant-voltage regulation, rail-to-rail current sensing (0V–45V), programmable analog dimming via CTRL pin, and up to 3000:1 True Color PWM™ dimming for automotive LED lighting systems.
For engineers reviewing the LT3519EMS#PBF datasheet, LT3519EMS#PBF pinout, LT3519EMS#PBF application, or LT3519EMS#PBF equivalent, this page delivers verified technical context, validated pin functions, confirmed topology flexibility (boost/SEPIC/buck-boost/buck), exact thermal and electrical specs per MSOP-16 package, and two rigorously cross-checked alternative parts for LED driver design continuity.
Technical Context
The LT3519EMS#PBF implements current-mode control with internal compensation, combining voltage feedback (FB pin, 1.22V reference) and rail-to-rail current sense feedback (ISP/ISN pins) to enable seamless transition between constant-current and constant-voltage regulation modes. Its error amplifier selects the dominant loop based on real-time comparison of FB and ISP–ISN signals.
It features a 400kHz fixed switching frequency, 94% max duty cycle, 250mV typical current sense threshold (adjustable via CTRL pin from 100mV to 250mV), open-LED fault detection via OPENLED pin (asserts when FB drops within 60mV of 1.22V), and programmable UVLO hysteresis using SHDN/UVLO pin with 1.22V falling threshold and 2.2μA internal pull-down current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 400kHz - enables compact magnetics and EMI filtering while maintaining high efficiency in automotive LED boost applications. |
| Internal Switch Rating | 45V VDS, 750mA ISW - supports LED strings up to ~38V output with margin for transients; eliminates need for external MOSFET in many 12V/24V automotive designs. |
| Integrated Schottky Diode | 0.8V forward drop at 500mA - reduces conduction loss and board area vs discrete diode; rated for 45V reverse blocking. |
| Current Sense Range | Rail-to-rail 0V–45V across ISP/ISN - allows LED cathode sensing in buck, boost, SEPIC, or buck-boost topologies without level-shifting circuitry. |
| CTRL Pin Adjustment | Linearly sets current sense threshold from 100mV to 250mV - enables precise analog dimming and fine-tuned current programming (e.g., ILED = (VCTRL – 0.1V)/(4 × RSENSE)). |
| PWM Dimming Ratio | Up to 3000:1 - achieved with external MOSFET disconnect during PWM low phase; preserves VC node charge for fast transient recovery. |
| Operating Temp Range | –40°C to +125°C junction - qualified for under-hood automotive environments and industrial LED lighting systems. |
Pinout & Package
LT3519EMS#PBF is housed in a 16-lead plastic MSOP package (3mm × 4.9mm, 0.5mm pitch) with exposed pad for thermal enhancement (θJA = 130°C/W). GND pins (1, 8, 9, 16) must be tied to a solid ground plane for optimal thermal and EMI performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (1, 8, 9, 16) | Power and signal ground reference | Multiple dedicated GND pins reduce ground impedance and improve stability; exposed pad must be soldered to PCB ground plane. |
| OPENLED (2) | Open-LED status output | Open-drain output asserting low when FB exceeds 1.16V (1.22V – 60mV); requires external pull-up for fault reporting in LED string monitoring. |
| PWM (3) | Dimming control input | Active-low enable/disable; internal pull-down ensures safe shutdown if left floating; disables oscillator and saves VC node state for fast PWM recovery. |
| SHDN/UVLO (4) | Shutdown and undervoltage lockout | 1.22V falling threshold with user-programmable hysteresis via resistor divider; 2.2μA internal pull-down enables precise UVLO rising edge setting. |
| VIN (5) | Main input supply | 3V–30V continuous operation (40V transient tolerant); requires local 1μF ceramic bypass capacitor placed adjacent to pin. |
| SW (6) | Switch node | Connects to inductor; high dI/dt path requiring minimized trace length and area to suppress EMI and ringing. |
| ANODE (7) | Integrated Schottky anode | Internally connected to SW node; used in boost/SEPIC configurations where Schottky conducts from SW to output. |
| ISP (11) | Current sense positive input | Non-inverting input of rail-to-rail current sense amplifier; bias current increases with VISP–VISN; connects to high side of RSENSE. |
| ISN (12) | Current sense negative input | Inverting input of current sense amplifier; connects to low side of RSENSE; together with ISP enables bidirectional sensing in buck-boost topologies. |
| FB (13) | Voltage feedback input | Regulates to 1.22V nominal; used for CV mode or open-LED protection; must not be left floating - tie to GND if unused. |
| CTRL (14) | Current threshold adjustment | Sets VISP–VISN threshold from 100mV to 250mV; connect to VREF (2V) for full-scale 250mV; linear analog dimming control. |
| VREF (15) | 2.0V precision reference output | Stable 2.0V ±20mV output capable of sourcing 100μA; used to bias CTRL, PWM, or external circuitry; improves system accuracy vs. relying on external references. |
| CATHODE (10) | Integrated Schottky cathode | Connects to output in boost mode; used with ANODE to form internal flyback path; eliminates need for external diode in standard boost LED drivers. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 45V/750mA switch + Schottky diode | Reduces BOM count by 2 components and PCB footprint vs discrete solutions; enables single-chip 4W LED drivers in MSOP-16. |
| Rail-to-rail ISP/ISN sensing (0V–45V) | Supports LED current sensing in any topology (buck, boost, SEPIC, buck-boost) without external op-amps or level shifters. |
| True Color PWM™ dimming (up to 3000:1) | Maintains consistent LED color point across dimming range by eliminating low-frequency current ripple artifacts common in analog-only dimming. |
| Programmable UVLO with hysteresis | Enables robust power sequencing in automotive systems - e.g., 6.2V turn-off / 8.2V turn-on thresholds prevent brown-out oscillation during cold-crank events. |
| Open-LED fault detection with latch | OPENLED pin latches last valid state during PWM idle periods, ensuring reliable fault reporting even during intermittent dimming cycles. |
| Internal compensation | Eliminates external compensation network, reducing design time and component count while guaranteeing stability across all supported topologies. |
Applications
| Automotive Headlamp Driver | Industrial Panel Backlight |
|---|---|
|
Use Scenario: Driving 38V, 100mA white LED string from 6V–30V automotive battery with cold-crank tolerance. IC Role / Device Role / Timing Role: Constant-current LED driver with 400kHz switching, integrated Schottky, and open-LED fault reporting via OPENLED pin. Use Value: Eliminates external MOSFET and diode; achieves >92% efficiency at 12V input; meets AEC-Q100 stress requirements via –40°C to +125°C operation. |
Use Scenario: Powering 16V, 150mA LED array in factory HMI panel with variable input (6V–24V) and EMI-sensitive environment. IC Role / Device Role / Timing Role: Buck-boost LED driver using ISP/ISN rail-to-rail sensing to regulate current independent of input/output polarity relationship. Use Value: Single IC supports wide VIN range without topology change; 78% efficiency at 12V input; OPENLED pin enables predictive maintenance alerts. |
| Commercial Signage Lighting | Medical Device Indicator |
|
Use Scenario: Driving 24V, 150mA LED string in outdoor signage with 3000:1 PWM dimming for daylight-to-night ambient adaptation. IC Role / Device Role / Timing Role: Boost LED driver with external MOSFET disconnect during PWM low phase to preserve VC node charge and ensure <1μs recovery. Use Value: True Color PWM™ prevents color shift at low brightness; 94% peak efficiency minimizes thermal load in sealed enclosures. |
Use Scenario: Providing stable 9V, 500mA LED current in Class II medical device with strict low-noise and safety isolation requirements. IC Role / Device Role / Timing Role: Buck-mode LED driver using ANODE/CATHODE pins to isolate LED return path from main power ground. Use Value: Internal Schottky avoids external high-voltage diode; CTRL pin enables calibrated analog dimming for compliance with IEC 60601-1 luminance limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EMS#PBF | 400kHz synchronous boost controller (external MOSFETs), no integrated switch or diode; supports higher output power (>10W). | Requires external high-side and low-side MOSFETs plus Schottky; suited for >500mA LED strings where thermal management demands discrete FETs. | Select LTC3783EMS#PBF when output current exceeds 750mA or when synchronous rectification is required for >95% efficiency. |
| LT3965EFE#PBF | 4-channel 500mA automotive LED driver with I2C interface, individual channel PWM, and built-in diagnostics (open/short LED detection). | Multi-channel digital control vs single-channel analog/PWM; includes fault logging and programmable safety timers per channel. | Select LT3965EFE#PBF for multi-zone lighting (e.g., adaptive front lighting systems) requiring ASIL-B compliance and diagnostic coverage. |
Compared with LTC3783EMS#PBF, LT3519EMS#PBF integrates switch and diode for lower BOM cost and smaller footprint but limits max current to 750mA; compared with LT3965EFE#PBF, it lacks digital control and multi-channel capability but offers simpler analog/PWM dimming and lower system-level complexity for single-string applications.
Availability
LT3519EMS#PBF is available at Aetrix Electronics and suitable for automotive headlamp systems, industrial HMI backlighting, commercial signage illumination, and medical indicator lighting requiring stable component supply, AEC-Q100-aligned reliability, and long-term production continuity.
Supply support for LT3519EMS#PBF 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
Analog Devices acquired Linear Technology in 2017 and maintains full product support, datasheet documentation, and application engineering for legacy Linear parts including the LT3519 family.
The LT3519 series was designed specifically for high-reliability, wide-input automotive LED lighting applications-emphasizing integrated power stages, robust fault protection, and flexible topology support without external compensation.
FAQ
What is the maximum continuous input voltage rating for LT3519EMS#PBF?
The LT3519EMS#PBF supports continuous operation from 3V to 30V on the VIN pin. Absolute maximum nonrepetitive transient rating is 40V for one second, making it suitable for automotive battery systems with load-dump spikes. Operation above 30V requires external clamping or derating per manufacturer guidelines.
Does LT3519EMS#PBF support buck-mode LED driving?
Yes, LT3519EMS#PBF supports buck-mode LED driving using its rail-to-rail ISP/ISN current sense inputs and ANODE/CATHODE pins. In buck configuration, the internal Schottky diode is bypassed, and external PNP/NPN transistors (e.g., FMMT555/FMMT494) are used to steer current, enabling efficient 500mA LED drive from 12V–30V inputs as verified in Typical Application TA04a.
How is open-LED fault detection implemented in LT3519EMS#PBF?
LT3519EMS#PBF monitors the FB pin voltage and asserts the OPENLED pin low when FB rises within ~60mV of its 1.22V regulation threshold (i.e., above 1.16V). This occurs only when the LED string opens and the voltage loop takes control - the OPENLED pin is open-drain and requires an external pull-up resistor to report the fault to system microcontroller or indicator circuit.
What is the function of the CTRL pin on LT3519EMS#PBF?
The CTRL pin on LT3519EMS#PBF adjusts the current sense threshold voltage (VISP–VISN) linearly from 100mV to 250mV. At 0.1V–1.0V, ILED = (VCTRL – 0.1V)/(4 × RSENSE); above 1.2V, it clamps to 250mV for full-scale current. This enables precise analog dimming and calibration without changing RSENSE.
Can LT3519EMS#PBF be used in SEPIC or buck-boost topologies?
Yes, LT3519EMS#PBF supports SEPIC and buck-boost topologies due to its rail-to-rail ISP/ISN current sensing (0V–45V) and flexible feedback architecture. The block diagram confirms dual-loop control where either voltage (FB) or current (ISP–ISN) dominates - enabling stable regulation regardless of input/output voltage relationship, as demonstrated in Typical Application TA03a (buck-boost 150mA LED driver).
LT3519EMS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- SEPIC, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 30V
- Voltage - Output:
- -
- Current - Output / Channel:
- 750mA (Switch)
- Frequency:
- 400kHz
- Dimming:
- Analog, PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP
LT3519EMS#PBF FAQ
1.How can I place an order for LT3519EMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3519EMS#PBF 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 LT3519EMS#PBF reliable?
The price and inventory of LT3519EMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3519EMS#PBF is usually 5 days.
3.What payment methods are accepted for LT3519EMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3519EMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3519EMS#PBF?
LT3519EMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3519EMS#PBF 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 LT3519EMS#PBF?
For technical support, including LT3519EMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3519EMS#PBF requirements.
6.How does Aetrix verify that LT3519EMS#PBF is sourced from the original manufacturer or authorized distributors?
All LT3519EMS#PBF 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 LT3519EMS#PBF meets industry standards.
7.What is the process for return or replacement of LT3519EMS#PBF?
All LT3519EMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3519EMS#PBF, 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 LT3519EMS#PBF part is unused and in its original packaging.
Return procedure for LT3519EMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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