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Analog Devices Inc. LT3797EUKG#PBF
- Part No.:
- LT3797EUKG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 52-WFQFN, 47 Leads, Exposed Pad
- Datasheet:
-
LT3797EUKG#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 52QFN
- Quantity:
- Payment:
- Shipping:
Inventory:5,342
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Product details
Overview
LT3797EUKG#PBF from Analog Devices is a triple-output DC/DC LED controller IC designed for independent high-side current sensing and flexible topology selection (boost, buck, buck-boost, SEPIC, flyback) per channel. It operates from 2.5V to 40V input, delivers rail-to-rail LED current sense range (0V–100V), supports 3000:1 PWM dimming, and integrates a 7.5V INTVCC supply for N-channel gate drivers - used in RGB lighting, automotive headlamps, and large-format displays.
For engineers reviewing the LT3797EUKG#PBF datasheet, LT3797EUKG#PBF pinout, LT3797EUKG#PBF application, or LT3797EUKG#PBF equivalent, key selection considerations include per-channel analog dimming via CTRL pins, high-side ISP/ISN sensing capability, FBH-referred voltage feedback for open-LED protection, TG driver support for PMOS LED disconnect, and programmable soft-start with fault flag reporting per channel.
Technical Context
The LT3797EUKG#PBF implements fixed-frequency current-mode control with three fully independent switching regulators sharing only the oscillator and integrated INTVCC power supply. Each channel features dedicated error amplifiers (VC1–VC3), high-side current sense inputs (ISP1–ISP3/ISN1–ISN3), and FBH-referenced voltage feedback (FBH1–FBH3) enabling dual-loop regulation (current + voltage) per string.
Its architecture supports topology flexibility by allowing each channel to operate in boost, buck, or buck-boost mode - enabled by high-side current sensing and FBH referenced to ISP rather than GND. The integrated 7.5V INTVCC regulator powers all gate drivers and internal circuitry, while TG outputs level-shift PWM signals to drive external P-channel MOSFETs for LED disconnection and overvoltage protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 40V continuous; withstands 60V transients - enables direct battery connection in 12V/24V automotive and industrial systems. |
| LED Current Sense Range | Rail-to-rail 0V to 100V across ISP/ISN - supports high-side sensing in boost and buck-boost topologies without level-shifting circuitry. |
| Switching Frequency | 100kHz to 1MHz, adjustable via RT resistor or synchronizable to external clock - allows EMI optimization and inductor size reduction. |
| PWM Dimming Ratio | 3000:1 - enables precise brightness control in architectural and stage lighting applications. |
| INTVCC Output | 7.5V ±3.5%, regulated - powers N-channel gate drivers and internal logic, eliminating need for external bias supply. |
| Fault Reporting | Independent FLT1–FLT3 open-collector outputs - signal per-channel faults including open-LED, overcurrent, overvoltage, thermal shutdown, and VIN OVLO. |
| Analog Dimming Control | CTRL1–CTRL3 pins adjust LED current threshold from 0mV to 250mV linearly - enables temperature-compensated dimming or closed-loop current trimming. |
Pinout & Package
LT3797EUKG#PBF is housed in a 52-lead 7mm × 8mm plastic QFN package (UKG) with exposed thermal pad (Pin 53 = GND). The package supports θJA = 28°C/W and requires soldering of the exposed pad to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP1–ISP3 / ISN1–ISN3 | High-side LED current sense inputs | Kelvin-connected to external sense resistor; enable accurate current regulation regardless of ground path impedance. |
| FBH1–FBH3 | Voltage feedback reference inputs | Referenced to ISP pins; set |ISP–FBH| = 1.25V for open-LED protection or constant-voltage regulation. |
| TG1–TG3 | P-channel MOSFET gate drivers | Level-shifted PWM outputs driving external PMOS between ISP and (ISP – 6.5V); provide LED disconnect and overvoltage cutoff. |
| GATE1–GATE3 | N-channel MOSFET gate drivers | Drive external NMOS switches between INTVCC and GND; support up to 3300pF load with 25ns rise/fall times. |
| CTRL1–CTRL3 | Analog dimming threshold inputs | Set LED current sense threshold from 0.2V to 1.2V; 0.3V = ~25mV (1/10 scale), 1.1V = ~200mV (8/10 scale), >1.2V = 250mV full scale. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent LED channels | Each channel has dedicated ISP/ISN, FBH, TG, GATE, VC, SS, FLT, and PWM - enables mixed-topology designs (e.g., boost + buck + SEPIC) on single IC. |
| High-side current sensing | Supports sensing at up to 100V common-mode voltage - eliminates need for isolated amplifiers or shunt-to-ground configurations. |
| Integrated 7.5V INTVCC supply | Regulated output powers all gate drivers and internal circuitry - reduces BOM count and improves efficiency vs. external LDO. |
| Per-channel fault flags (FLT1–FLT3) | Open-collector outputs report open-LED, overcurrent, overvoltage, thermal, and VIN OVLO - enables granular system-level diagnostics and fail-safe response. |
| Programmable soft-start (SS1–SS3) | Capacitor-controlled ramp per channel - prevents inrush current and ensures controlled startup in multi-string arrays. |
Applications
| Automotive Headlamp Systems | RGB Stage Lighting |
|---|---|
Use Scenario: Driving separate white, amber, and red LED strings in adaptive front-lighting systems (AFS) with dynamic beam shaping. IC Role / Device Role / Timing Role: Triple-output LED controller managing independent current regulation, thermal foldback, and fault isolation per color channel. Use Value: Enables pixel-level intensity control and rapid fault detection (e.g., open-circuit LED) without disabling entire headlamp assembly. | Use Scenario: Controlling high-brightness RGB LED modules in theatrical and concert lighting fixtures requiring precise color mixing. IC Role / Device Role / Timing Role: Synchronized triple-channel dimming controller supporting 3000:1 PWM ratio and analog current scaling for smooth color transitions. Use Value: Eliminates visible flicker during slow fades and maintains consistent chromaticity across intensity range via per-channel calibration. |
| Billboard & Large Display Backlighting | Industrial Machine Vision Illumination |
Use Scenario: Powering long LED strings in outdoor digital signage with wide ambient temperature (-40°C to +125°C) and input voltage variation (9–36V). IC Role / Device Role / Timing Role: Robust triple-channel controller with VIN transient ride-through (60V), rail-to-rail sensing, and programmable UVLO/OVLO. Use Value: Ensures uninterrupted operation during vehicle battery load-dump events and maintains uniform brightness despite line voltage sag. | Use Scenario: Driving high-current monochrome LED arrays in automated optical inspection systems requiring strobed illumination synchronized to camera exposure. IC Role / Device Role / Timing Role: Precision current controller with fast PWM response (<300ns TG turn-on), independent soft-start, and fault-flag-triggered safety shutdown. Use Value: Guarantees repeatable light intensity per frame and immediate LED disable on thermal or overcurrent fault to protect optics and sensors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | Single-output synchronous boost controller; no integrated INTVCC; requires external gate drivers and bias supply. | Suitable only for single-string boost designs; lacks per-channel fault flags, FBH protection, and TG drivers. | Select when cost-sensitive single-string design suffices and board space permits external components. |
| MAX16834ATL+T | Dual-output LED controller; supports only boost/buck-boost; no high-side sensing; max 1000:1 PWM dimming. | Limited to two channels; no rail-to-rail ISP/ISN range; lacks TG drivers for PMOS disconnect and open-LED protection. | Choose for compact dual-string applications where 3000:1 dimming and per-channel voltage loop are not required. |
Compared with LTC3783EFE#PBF and MAX16834ATL+T, the LT3797EUKG#PBF uniquely delivers three independent high-side-sensing channels with integrated INTVCC, TG drivers, FBH-referenced protection, and 3000:1 dimming - making it the only option for robust, scalable multi-string LED systems demanding fault granularity and topology flexibility.
Availability
LT3797EUKG#PBF is available at Aetrix Electronics and suitable for automotive headlamps, RGB stage lighting, and large-display backlighting requiring stable component supply, extended temperature operation (–40°C to +125°C), and long-term production continuity.
Supply support for LT3797EUKG#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 (now part of Analog Devices, Inc. following merger with Linear Technology) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT3797 product line was designed specifically for high-reliability, multi-string LED lighting systems requiring independent channel control, topology flexibility, and comprehensive fault protection - targeting automotive, industrial, and professional display markets.
FAQ
What is the maximum input voltage the LT3797EUKG#PBF can withstand?
The LT3797EUKG#PBF supports continuous operation up to 40V input and can withstand transient voltages up to 60V. Its internal VIN overvoltage lockout activates at 41V (typical), shutting down all channels and resetting soft-start to protect downstream circuitry. This makes the LT3797EUKG#PBF suitable for 24V automotive and industrial bus applications with load-dump immunity.
How does the LT3797EUKG#PBF support high-side current sensing?
The LT3797EUKG#PBF enables true high-side current sensing via dedicated ISP1–ISP3 and ISN1–ISN3 pins rated for 0V to 100V common-mode voltage. Its current sense amplifier input common-mode range covers the full 100V span, and the FBH pins are referenced to ISP - allowing accurate regulation even when the LED string cathode is not grounded. This eliminates the need for isolated amplifiers or shunt-to-ground configurations in boost and buck-boost topologies.
Can the LT3797EUKG#PBF drive P-channel MOSFETs for LED disconnect?
Yes, the LT3797EUKG#PBF includes dedicated TG1–TG3 outputs that level-shift PWM signals to drive external P-channel MOSFETs between ISP and (ISP – 6.5V). When an open-LED or overvoltage condition occurs, the corresponding TG pin drives high to disconnect the LED string - providing hardware-level protection independent of microcontroller intervention. This feature is integral to the LT3797EUKG#PBF's fault safety architecture.
What is the purpose of the FBH1–FBH3 pins on the LT3797EUKG#PBF?
The FBH1–FBH3 pins on the LT3797EUKG#PBF serve as voltage feedback references tied to the ISP pins, enabling |ISP–FBH| regulation at 1.25V (typical). They support constant-voltage operation during open-LED events and provide overvoltage protection: if |ISP–FBH| exceeds 1.3V (typical), the corresponding TG pin pulls high to disconnect the LED string. Connecting FBH to ISP disables voltage regulation and forces current-only control - a key configuration choice in the LT3797EUKG#PBF's dual-loop architecture.
Does the LT3797EUKG#PBF require external components for soft-start?
Yes, the LT3797EUKG#PBF implements per-channel soft-start using external capacitors on SS1–SS3 pins. Each SS pin controls the ramp rate of its associated VC pin voltage, modulating the peak switch current during startup. A typical 10nF capacitor yields ~1ms soft-start time; larger values extend ramp duration to limit inrush current in high-power LED arrays. No internal soft-start capacitor exists - the LT3797EUKG#PBF relies entirely on these external components for controlled turn-on behavior.
LT3797EUKG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 52-WFQFN, 47 Leads, Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Flyback, SEPIC, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 3
- Voltage - Supply (Min):
- 2.5V
- Voltage - Supply (Max):
- 40V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 100kHz ~ 1MHz
- Dimming:
- Analog, PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 52-QFN (7x8)
LT3797EUKG#PBF FAQ
1.How can I place an order for LT3797EUKG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3797EUKG#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 LT3797EUKG#PBF reliable?
The price and inventory of LT3797EUKG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3797EUKG#PBF is usually 5 days.
3.What payment methods are accepted for LT3797EUKG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3797EUKG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3797EUKG#PBF?
LT3797EUKG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3797EUKG#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 LT3797EUKG#PBF?
For technical support, including LT3797EUKG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3797EUKG#PBF requirements.
6.How does Aetrix verify that LT3797EUKG#PBF is sourced from the original manufacturer or authorized distributors?
All LT3797EUKG#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 LT3797EUKG#PBF meets industry standards.
7.What is the process for return or replacement of LT3797EUKG#PBF?
All LT3797EUKG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3797EUKG#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 LT3797EUKG#PBF part is unused and in its original packaging.
Return procedure for LT3797EUKG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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