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Analog Devices Inc. LT3517HUF#TRPBF
- Part No.:
- LT3517HUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-WQFN Exposed Pad
- Datasheet:
-
LT3517HUF#TRPBF.pdf
- Description:
- IC LED DRVR RGLTR PWM 1.5A 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,322
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Product details
Overview
LT3517HUF#TRPBF from Analog Devices (formerly Linear Technology) is a constant-frequency current-mode DC/DC LED driver IC with an integrated 1.5A/45V power switch, supporting boost, buck, and buck-boost topologies. It delivers precise constant-current regulation via 100mV high-side current sensing, enables 5000:1 true-color PWM dimming, and operates across 3V–30V input with transient tolerance to 40V - ideal for automotive interior lighting and industrial display backlighting.
For engineers reviewing the LT3517HUF#TRPBF datasheet, LT3517HUF#TRPBF pinout, LT3517HUF#TRPBF application, or LT3517HUF#TRPBF equivalent, key selection considerations include its –40°C to 150°C guaranteed junction temperature range, programmable 250kHz–2.5MHz switching frequency, open-LED protection, and gate driver for external PMOS LED disconnect.
Technical Context
The LT3517HUF#TRPBF implements dual-loop regulation: a voltage loop (FB pin referenced to 1.01V) and a current loop (ISP/ISN differential sense with CTRL-adjustable threshold), enabling seamless transition between constant-voltage and constant-current modes. Its internal 1.5A switch features 300mV typical VCE(SAT) at 1A and supports synchronous operation via the SYNC pin with 20% slower RT-programmed frequency.
It integrates a transconductance error amplifier (550µS) on the VC pin for loop compensation, a soft-start circuit (SS pin), and independent PWM and analog (CTRL) dimming controls - the former enabling 5000:1 dimming ratio with stored VC state for fast recovery, the latter providing 10:1 linear current scaling down to 10mV sense threshold.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Limit | 1.5A typical; ensures safe drive of high-brightness LED strings up to ~35W in buck mode at 24V input. |
| Input Voltage Range | 3V–30V continuous, 40V transient; supports 12V/24V automotive rails and accommodates load-dump surges without external clamping. |
| Current Sense Threshold | 100mV nominal (±4mV over temp); enables accurate LED current setting with low-power, high-precision 100mΩ sense resistor. |
| Switching Frequency Range | 250kHz–2.5MHz; adjustable via RT resistor or external SYNC clock - allows optimization for efficiency (low-f) or compact layout (high-f). |
| Junction Temperature Range | –40°C to +150°C; H-grade qualification enables use in under-hood automotive modules and high-ambient industrial enclosures. |
| PWM Dimming Ratio | 5000:1 true-color; achieved by disabling switching during PWM low phase while preserving VC node charge for sub-2µs recovery. |
| Shutdown Current | <1µA; minimizes battery drain in always-on vehicle systems during sleep mode. |
Pinout & Package
LT3517HUF#TRPBF is housed in a thermally enhanced 16-lead (4mm × 4mm) plastic QFN package with exposed pad (Pin 17) soldered to PCB ground for thermal and electrical integrity. The package supports high-power density designs with θJA = 36°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Power Switch Output | Drives external inductor/diode; requires minimal trace area to reduce EMI and switching losses. |
| VIN | Main Input Supply | Accepts 3V–30V; must be bypassed locally with ≥2.2µF ceramic capacitor for stable high-current pulsed operation. |
| ISP / ISN | High-Side Current Sense Inputs | Differential pair measuring voltage across external sense resistor; rail-to-rail operation supports wide LED string voltage ranges. |
| TG | Top Gate Driver Output | Drives external PMOS between VISP and (VISP – 7V); includes internal 7V clamp to protect MOSFET gate oxide. |
| CTRL | Analog Current Setpoint Input | Scales current sense threshold from 10mV to 100mV; 0–1V input yields 10:1 analog dimming without PWM timing constraints. |
| PWM | Digital Dimming Control | Active-low signal disabling main switch and saving VC state; enables 5000:1 dimming with synchronized rising edges for optimal ratio. |
| RT | Frequency Programming | Resistor-to-GND sets oscillator frequency; values from 4.02kΩ (2.5MHz) to 90.9kΩ (250kHz) per datasheet Table 4. |
| SYNC | External Clock Input | Accepts CMOS-level clock; forces synchronization when RT is configured for 20% lower frequency than SYNC signal. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1.5A/45V Power Switch | Eliminates external MOSFET and reduces BOM count in space-constrained LED drivers for displays and signage. |
| 100mV High-Side Current Sense | Minimizes power loss in sense resistor (e.g., 100mΩ dissipates only 10mW at 1A), improving thermal performance and accuracy. |
| 5000:1 True Color PWM Dimming | Maintains consistent LED chromaticity across full dimming range by avoiding low-duty-cycle color shift common in analog-only methods. |
| Open LED Protection | Disables switching and asserts fault condition if ISP–ISN voltage exceeds threshold - prevents overvoltage damage to LED string. |
| PMOS Gate Driver (TG Pin) | Enables active LED string disconnect during PWM off-time, preventing output capacitor discharge and ensuring fast dimming response. |
Applications
| Automotive Interior Lighting | Industrial Display Backlighting |
|---|---|
|
Use Scenario: LED dome lights, map lights, and ambient lighting in vehicles operating across –40°C to +125°C under-hood environments. IC Role / Device Role / Timing Role: Constant-current LED driver with load-dump transient protection and H-grade thermal rating for direct integration into lighting control modules. Use Value: Eliminates need for external surge protection and high-temp discrete switches, reducing system cost and board area by >30% versus discrete solutions. |
Use Scenario: High-brightness LCD backlights in factory HMIs, medical monitors, and outdoor kiosks requiring flicker-free dimming. IC Role / Device Role / Timing Role: Synchronous buck-boost LED controller delivering stable current despite wide input variation (e.g., 12–24V industrial supply). Use Value: 5000:1 PWM dimming preserves color fidelity at low brightness levels critical for medical imaging and precision visualization. |
| Avionic Cabin Lighting | Barcode Scanner Illumination |
|
Use Scenario: FAA-certified LED lighting in commercial aircraft cabins where reliability, EMI control, and extended temperature operation are mandatory. IC Role / Device Role / Timing Role: Dual-loop regulated LED driver with soft-start (SS pin) and low shutdown current (<1µA) for battery-backed emergency lighting. Use Value: Meets DO-160 Section 20 radiated emissions requirements due to minimized SW node area and integrated gate driver timing control. |
Use Scenario: Pulsed high-intensity illumination in handheld and fixed-mount barcode scanners requiring microsecond-level LED turn-on consistency. IC Role / Device Role / Timing Role: Fast-recovery PWM dimming controller using stored VC state to achieve <2µs LED current re-establishment after PWM edge. Use Value: Enables reliable scanning of low-contrast or damaged barcodes by eliminating current droop during repeated short-duration illumination bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3756IMSE#TRPBF | Higher 5A switch current, 100V rating, and separate high-/low-side sense inputs; no integrated VREF or TGEN pin. | Better suited for high-power architectural lighting (>50W) and AC-powered LED drivers; lacks PMOS disconnect driver. | Select LT3756IMSE#TRPBF when driving >2A LED loads or requiring >45V input; avoid if needing integrated TG driver or compact 4×4mm footprint. |
| LM3409QMYX/NOPB | 40V max switch, 1.25A current limit, no SYNC or TGEN; uses external N-channel MOSFET; 100mV sense threshold same. | Cost-optimized for consumer lighting; lacks H-grade temp rating and open-LED protection logic. | Choose LM3409QMYX/NOPB for non-automotive, commercial-grade applications below 125°C ambient; not qualified for automotive AEC-Q100. |
Compared with LT3517HUF#TRPBF, LT3756IMSE#TRPBF offers higher power capability but requires more external components and larger layout, while LM3409QMYX/NOPB reduces cost at the expense of thermal robustness and integrated protection features essential for mission-critical lighting.
Availability
LT3517HUF#TRPBF is available at Aetrix Electronics and suitable for automotive interior lighting, industrial display backlighting, avionic cabin lighting, and barcode scanner illumination requiring stable component supply across extended temperature and high-reliability environments.
Supply support for LT3517HUF#TRPBF 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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LT3517 belongs to Linear's high-reliability LED driver product line, engineered specifically for demanding constant-current applications where thermal resilience, dimming fidelity, and topology flexibility (buck/boost/buck-boost) are critical.
FAQ
What is the maximum operating junction temperature for LT3517HUF#TRPBF?
The LT3517HUF#TRPBF is guaranteed over a junction temperature range of –40°C to +150°C, with thermal shutdown activation above this limit. This H-grade rating enables deployment in under-hood automotive modules and high-ambient industrial enclosures where standard E- or I-grade variants would fail.
How does LT3517HUF#TRPBF achieve 5000:1 PWM dimming?
The LT3517HUF#TRPBF achieves 5000:1 true-color PWM dimming by disabling the main power switch and preserving the VC node charge state during PWM low periods. Recovery time is minimized to sub-2µs when PWM goes high, and external PMOS disconnect via the TG pin prevents output capacitor discharge - maintaining LED current fidelity across the full range.
Can LT3517HUF#TRPBF operate in buck, boost, and buck-boost configurations?
Yes, the LT3517HUF#TRPBF supports all three topologies. Its dual-loop architecture (voltage and current feedback) and flexible ISP/ISN sensing allow it to regulate LED current in buck mode (VIN > VLED), boost mode (VIN < VLED), and buck-boost mode (wide VIN/VLED ratio), with appropriate external component selection per application note.
What is the purpose of the TG pin on LT3517HUF#TRPBF?
The TG pin on LT3517HUF#TRPBF drives the gate of an external PMOS transistor placed in series with the LED string. It provides inverted PWM control and includes a 7V clamp to protect the MOSFET gate, enabling active LED disconnect during PWM off-time - which prevents output capacitor discharge and ensures rapid dimming response.
Does LT3517HUF#TRPBF include open-LED protection?
Yes, LT3517HUF#TRPBF includes dedicated open-LED protection. If the voltage across the ISP–ISN sense resistor falls below the threshold (indicating no current flow), the IC disables the main switch and holds the TG pin high to disconnect the LED string, preventing overvoltage stress on the output capacitors and LEDs.
LT3517HUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- True Color PWM™
- Package/Case:
- 16-WQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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 ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (4x4)
LT3517HUF#TRPBF FAQ
1.How can I place an order for LT3517HUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3517HUF#TRPBF 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 LT3517HUF#TRPBF reliable?
The price and inventory of LT3517HUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3517HUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3517HUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3517HUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3517HUF#TRPBF?
LT3517HUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3517HUF#TRPBF 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 LT3517HUF#TRPBF?
For technical support, including LT3517HUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3517HUF#TRPBF requirements.
6.How does Aetrix verify that LT3517HUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3517HUF#TRPBF 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 LT3517HUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3517HUF#TRPBF?
All LT3517HUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3517HUF#TRPBF, 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 LT3517HUF#TRPBF part is unused and in its original packaging.
Return procedure for LT3517HUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3517HUF#TRPBF Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
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BCR420UE6433HTMA1
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HV9910CLG-G
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CL2N8-G
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BCR420UW6-7
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