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Analog Devices Inc. LT3517EUF#PBF
- Part No.:
- LT3517EUF#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-WQFN Exposed Pad
- Datasheet:
-
LT3517EUF#PBF.pdf
- Description:
- IC LED DRVR RGLTR PWM 1.5A 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,313
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Product details
Overview
LT3517EUF#PBF from Analog Devices is a current-mode DC/DC LED driver IC with an integrated 1.5A, 45V power switch, supporting boost, buck, and buck-boost topologies. It delivers constant-current regulation via 100mV high-side current sensing and enables 5000:1 true-color PWM dimming for precision LED brightness control in automotive lighting and display backlighting.
For engineers reviewing the LT3517EUF#PBF datasheet, LT3517EUF#PBF pinout, LT3517EUF#PBF application, or LT3517EUF#PBF equivalent, key selection criteria include its 250kHz–2.5MHz adjustable switching frequency, open-LED protection, gate driver for PMOS LED disconnect, and operation across 3V–30V input with transient tolerance to 40V.
Technical Context
The LT3517EUF#PBF implements dual-loop regulation-combining a voltage feedback loop (FB pin threshold = 1.01V) and a unique current-sense loop (VISP–VISN = 100mV at full scale)-to seamlessly transition between constant-current and constant-voltage modes. Its internal 1.5A/45V switch supports high-efficiency LED driving across all three topologies without external MOSFETs.
Switching frequency is programmable via RT resistor (250kHz–2.5MHz) or synchronized to an external clock on SYNC, with built-in soft-start (SS pin), shutdown control (SHDN < 0.45V), and thermal protection. The CTRL pin provides 10:1 analog dimming while PWM enables ultra-high-ratio digital dimming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Limit | 1.5A typical; sets maximum LED drive capability without external current-limiting components. |
| Input Voltage Range | 3V to 30V continuous, with 40V transient tolerance; supports wide automotive battery and industrial supply rails. |
| Current Sense Threshold | 100mV (VISP–VISN); enables precise, low-loss LED current regulation using standard sense resistors. |
| Dimming Ratio | 5000:1 via PWM pin; achieves flicker-free, high-fidelity color rendering in display and illumination systems. |
| Switching Frequency Range | 250kHz to 2.5MHz; allows optimization of inductor size, efficiency, and EMI performance. |
| Operating Junction Temp | –40°C to +125°C; qualified for under-hood automotive and industrial ambient environments. |
| Package | 16-lead 4mm × 4mm QFN with exposed pad; provides low thermal resistance (θJC = 10°C/W) for high-power LED drive. |
Pinout & Package
LT3517EUF#PBF uses a 16-lead (4mm × 4mm) plastic QFN package with exposed thermal pad (Pin 17) soldered to PCB ground plane for optimal thermal management and EMI reduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Power Switch Output | Drives external inductor/diode; requires minimized trace area to reduce EMI radiation. |
| VIN | Main Input Supply | Accepts 3V–30V input; must be locally bypassed with ≥1µF low-ESR ceramic capacitor. |
| SHDN | Enable/Disable Control | Logic-high (>1.2V) enables operation; logic-low (<0.45V) reduces quiescent current to <1µA. |
| CTRL | Analog Dimming Input | Sets LED current threshold from 0–100mV; 0.1V–1V range enables 10:1 linear dimming. |
| PWM | Digital Dimming Input | Active-low signal disables switching and saves VC node state for fast recovery and 5000:1 dimming. |
| SYNC | External Clock Input | Accepts external clock up to 2.5MHz; RT resistor must be set for 20% lower free-running frequency. |
| FB | Voltage Feedback Input | Regulates output to 1.01V; used for overvoltage protection and constant-voltage mode in boost configurations. |
| ISP / ISN | High-Side Current Sense Inputs | Differential pair measuring voltage across external sense resistor; rail-to-rail operation supports wide LED string voltages. |
| TG | Top Gate Driver Output | Drives external PMOS for LED disconnect; clamped to VISP – 7V for safe gate drive. |
| TGEN | PMOS Enable Control | Logic-high (>1.5V) activates TG output; internal 40kΩ pull-down ensures safe default-off state. |
| VREF | 2.0V Reference Output | Provides stable 2.0V reference (±2%) for CTRL biasing and external circuitry; supplies up to 100µA. |
| RT | Frequency Set Input | Resistor-to-GND sets oscillator frequency; must not be left floating or capacitively loaded. |
| SS | Soft-Start Control | Capacitor-to-GND controls startup ramp rate; typical value is 0.1µF to limit inrush current. |
| VC | Error Amplifier Output | Compensation node for current/voltage loop stability; typically uses 10nF capacitor to GND. |
| GND | Ground / Exposed Pad | Thermal and electrical ground; exposed pad (Pin 17) must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Triple-Topology Operation | Configurable as boost, buck, or buck-boost LED driver-no topology-specific external components required. |
| True Color PWM™ Dimming | 5000:1 dimming ratio preserves LED chromaticity and eliminates visible flicker in high-end displays. |
| Open LED Protection | Automatic shutdown when ISP/ISN detect no current flow-prevents overvoltage damage to LED strings. |
| PMOS LED Disconnect Driver | Integrated TG output with 7V clamp enables fast, reliable LED current path isolation during PWM off-time. |
| Adjustable Frequency with Sync | RT resistor or SYNC pin allows system-level clock alignment-critical for EMI reduction in multi-rail designs. |
| Low Shutdown Current | <1µA shutdown quiescent current extends battery life in portable and always-on automotive lighting systems. |
Applications
| Automotive Headlamp Control | Industrial Display Backlighting |
|---|---|
Use Scenario: Adaptive front-lighting system (AFS) requiring dynamic beam shaping and intensity modulation across varying road conditions and ambient light. IC Role / Device Role / Timing Role: Constant-current LED driver regulating multiple high-brightness LED strings in buck-boost configuration with load-dump transient immunity. Use Value: Withstands 40V transients per ISO 7637-2, supports 300mA–1.5A LED currents, and enables seamless dimming transitions via combined CTRL+PWM control. | Use Scenario: High-resolution medical imaging display requiring uniform, flicker-free backlighting with precise luminance control across temperature and aging. IC Role / Device Role / Timing Role: Boost-mode LED driver powering white LED arrays with 1.01V FB reference accuracy and 5000:1 PWM dimming resolution. Use Value: Maintains ±1% LED current accuracy over –40°C to +125°C, minimizes color shift via true-color dimming, and simplifies layout with integrated switch and gate driver. |
| Aerospace Avionic Lighting | Barcode Scanner Illumination |
Use Scenario: Cockpit panel lighting where reliability, EMI compliance, and wide input voltage range are critical under aircraft power bus fluctuations. IC Role / Device Role / Timing Role: Buck-mode LED driver operating from 18–32V nominal aircraft bus, delivering regulated 350mA with open-LED fault detection. Use Value: Qualified to –40°C to +125°C junction temp, features exposed-pad QFN for robust thermal performance, and includes SYNC for clock-domain isolation in avionics systems. | Use Scenario: High-speed handheld barcode scanner requiring rapid LED strobing with minimal latency and consistent optical output. IC Role / Device Role / Timing Role: Buck-boost LED driver enabling instant on/off control via PWM pin with stored VC state for sub-microsecond recovery. Use Value: Achieves <2µs minimum PWM pulse width at 2MHz switching, supports 100mA–1A drive range, and integrates soft-start to prevent mechanical vibration in scanning mechanisms. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | Higher 3A switch current, 60V rating, but no integrated PWM dimming control; requires external PWM generator. | Better suited for high-power industrial LED arrays (>1.5A), less ideal for compact display backlighting needing integrated dimming. | Select LTC3783EFE#PBF only when >1.5A drive or >45V operation is required and external dimming control is acceptable. |
| MAX16820ATP+ | Lower 1.2A switch current, fixed 500kHz frequency, no SYNC or adjustable RT; lacks buck-boost topology support. | Targeted at cost-sensitive automotive interior lighting with simpler boost-only requirements and lower thermal demands. | Choose MAX16820ATP+ for basic boost LED drivers where 5000:1 dimming, triple topology, or thermal robustness are not required. |
Compared with LTC3783EFE#PBF and MAX16820ATP+, the LT3517EUF#PBF uniquely combines triple-topology flexibility, integrated 5000:1 PWM dimming, and 1.5A/45V switching in a thermally optimized QFN-making it optimal for space-constrained, high-fidelity LED systems demanding both performance and design simplicity.
Availability
LT3517EUF#PBF is available at Aetrix Electronics and suitable for automotive headlamps, industrial display backlighting, and avionic lighting requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LT3517EUF#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 (formerly Linear Technology) is a global leader in high-performance analog, mixed-signal, and power management ICs, serving automotive, industrial, communications, and healthcare markets.
The LT3517 product line was designed specifically for high-reliability, multi-topology LED driving in harsh environments-emphasizing integrated protection, wide input range, and precision dimming for next-generation lighting systems.
FAQ
What is the maximum LED current supported by the LT3517EUF#PBF?
The LT3517EUF#PBF supports a typical switch current limit of 1.5A, enabling direct drive of high-brightness LED strings up to 1.5A without external MOSFETs. Its current sense threshold is fixed at 100mV, so actual LED current is determined by the external sense resistor value (e.g., 100mΩ yields 1A). The LT3517EUF#PBF datasheet specifies 1.5A typical, 1.9A maximum, and 2.3A absolute peak under transient conditions.
Does the LT3517EUF#PBF support buck-boost LED driving?
Yes, the LT3517EUF#PBF natively supports buck, boost, and buck-boost topologies without external reconfiguration. Its dual-loop architecture (current + voltage feedback) and high-side current sensing allow seamless operation across all three modes. Application circuits in the LT3517EUF#PBF datasheet explicitly demonstrate buck-boost operation with 300mA output at 8V–16V input, confirming full functional validation for this topology.
How does the LT3517EUF#PBF achieve 5000:1 PWM dimming?
The LT3517EUF#PBF achieves 5000:1 true-color PWM dimming by combining fast-switching capability (up to 2.5MHz), stored VC node state during PWM low periods, and external PMOS LED disconnect via the TG driver. For example, at 2MHz switching, the minimum 2µs PWM pulse width and 10ms maximum period yield exactly 5000:1. The LT3517EUF#PBF maintains LED color fidelity by avoiding current overshoot and ensuring clean turn-on/turn-off transitions.
What is the role of the TGEN pin on the LT3517EUF#PBF?
The TGEN pin on the LT3517EUF#PBF enables or disables the internal top-gate driver (TG output). When pulled to ≥1.5V, TGEN activates the TG pin to drive an external PMOS transistor for LED string disconnect-critical for eliminating residual current during PWM off-time and improving dimming contrast. An internal 40kΩ pull-down ensures TG remains inactive if TGEN is left unconnected, enhancing system safety.
Can the LT3517EUF#PBF operate from a 24V automotive supply?
Yes, the LT3517EUF#PBF operates continuously from 3V to 30V input and withstands nonrepetitive 40V transients per ISO 7637-2-making it fully compatible with 24V automotive systems. Its thermal design (θJC = 10°C/W) and –40°C to +125°C operating junction temperature range ensure reliable performance under hood conditions. Typical applications include 24V-input buck-mode LED drivers for commercial vehicle lighting.
LT3517EUF#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- True Color PWM™
- Package/Case:
- 16-WQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- 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:
- 1.5A (Switch)
- Frequency:
- 250kHz ~ 2.5MHz
- Dimming:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (4x4)
LT3517EUF#PBF FAQ
1.How can I place an order for LT3517EUF#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3517EUF#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 LT3517EUF#PBF reliable?
The price and inventory of LT3517EUF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3517EUF#PBF is usually 5 days.
3.What payment methods are accepted for LT3517EUF#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3517EUF#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3517EUF#PBF?
LT3517EUF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3517EUF#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 LT3517EUF#PBF?
For technical support, including LT3517EUF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3517EUF#PBF requirements.
6.How does Aetrix verify that LT3517EUF#PBF is sourced from the original manufacturer or authorized distributors?
All LT3517EUF#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 LT3517EUF#PBF meets industry standards.
7.What is the process for return or replacement of LT3517EUF#PBF?
All LT3517EUF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3517EUF#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 LT3517EUF#PBF part is unused and in its original packaging.
Return procedure for LT3517EUF#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3517EUF#PBF Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
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BCR420UE6433HTMA1
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LYT1604D-TL
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HV9910CLG-G
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CL2N8-G
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BCR420UW6-7
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BCR420UFD-7
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