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Analog Devices Inc. LT3797IUKG#PBF
- Part No.:
- LT3797IUKG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 52-WFQFN, 47 Leads, Exposed Pad
- Datasheet:
-
LT3797IUKG#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 52QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,073
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Product details
Overview
LT3797IUKG#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, supports rail-to-rail LED current sense (0V–100V), delivers 3000:1 PWM dimming, and integrates a 7.5V INTVCC supply for N-channel gate drivers - used in automotive RGB lighting and large-format displays.
For engineers reviewing the LT3797IUKG#PBF datasheet, LT3797IUKG#PBF pinout, LT3797IUKG#PBF application, or LT3797IUKG#PBF equivalent, key selection considerations include its triple-channel independent fault flag reporting (FLT1–3), programmable soft-start per channel (SS1–3), high-side ISP/ISN sensing architecture, and compatibility with external P-channel LED disconnect MOSFETs via TG1–3 drivers.
Technical Context
The LT3797IUKG#PBF implements fixed-frequency current-mode control with three fully replicated error amplifiers (VC1–3), independent PWM inputs (PWM1–3), and dedicated fault detection per channel (FLT1–3). Its FBH pins reference ISP for voltage-loop regulation (|ISP–FBH| = 1.25V typical), enabling open-LED protection and overvoltage shutdown at 1.3V threshold.
Each channel features high-side current sensing (ISP1–3/ISN1–3), rail-to-rail common-mode range (0V–100V), and analog dimming via CTRL1–3 (0.2V–1.2V linear range). The integrated INTVCC converter (7.5V ±0.35V) powers gate drivers and supports VIN transients up to 60V with automatic shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 40V continuous; 60V transient ride-through with automatic shutdown |
| Switching Frequency | 100kHz to 1MHz, adjustable via RT resistor or synchronizable to external clock |
| LED Current Sense Range | Rail-to-rail 0V–100V common-mode; 250mV default threshold (adjustable 17–250mV via CTRL) |
| PWM Dimming Ratio | 3000:1 - enables precise brightness control in high-dynamic-range lighting |
| INTVCC Output | 7.5V regulated supply (±0.35V) for gate drivers; 5.2V UVLO with 0.4V hysteresis |
| Fault Protection | Per-channel open-LED, overcurrent, overvoltage (|ISP–FBH| >1.3V), thermal (>165°C), and VIN OVLO |
| Operating Temperature | –40°C to +125°C junction - qualified for automotive and industrial environments |
Pinout & Package
LT3797IUKG#PBF is housed in a 52-lead 7mm × 8mm plastic QFN package (UKG) with exposed pad (Pin 53) soldered to PCB ground. Thermal resistance θJA = 28°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP1–3 / ISN1–3 | High-side LED current sense inputs | Kelvin-connected to external sense resistor; enable rail-to-rail 0V–100V sensing without ground-referenced constraints |
| FBH1–3 | Voltage feedback reference input | Sets |ISP–FBH| = 1.25V for CV regulation; triggers TG high on overvoltage (>1.3V) or open-LED detection |
| TG1–3 | P-channel MOSFET gate driver output | Drives external PMOS between ISP and (ISP – 6.5V); provides LED disconnect during fault or idle mode |
| GATE1–3 | N-channel MOSFET gate driver output | Drives NMOS switch between INTVCC and GND; 220ns min on-time, 200ns min off-time |
| CTRL1–3 | Analog dimming threshold control | 0.2V–1.2V input sets LED current threshold from 17mV to 250mV; <150mV forces idle mode |
| FLT1–3 | Open-collector fault flag output | Active-low per-channel fault reporting: VIN OVLO, thermal, INTVCC UVLO, open-LED, overcurrent, overvoltage |
| SS1–3 | Soft-start timing capacitor connection | External capacitor sets individual channel soft-start ramp; reset on fault or EN/UVLO disable |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent boost/buck/buck-boost LED controllers | Enables mixed-topology design per channel - e.g., boost for red LEDs, buck for blue/green - without external reconfiguration |
| High-side current sensing (ISP/ISN) | Eliminates ground-loop interference and supports floating LED strings; compatible with common-cathode or common-anode layouts |
| Integrated 7.5V INTVCC power supply | Reduces external BOM count; powers all gate drivers and internal logic; shuts down cleanly at VIN >41V |
| Per-channel fault isolation and reporting | FLT1–3 outputs allow system-level diagnostics without cross-channel interference - critical for safety-critical lighting |
| Programmable soft-start per channel (SS1–3) | Prevents inrush current in multi-string systems; independent timing avoids cascaded turn-on stress |
| 3000:1 PWM dimming with TG-driven PMOS disconnect | Enables flicker-free dimming down to 0.033% duty cycle; TG drivers ensure full LED string isolation during off periods |
Applications
| Automotive Adaptive Headlamps | RGB Stage Lighting |
|---|---|
Use Scenario: Dynamic beam shaping using independently controlled red, green, and blue LED arrays in headlamp modules. IC Role / Device Role / Timing Role: LT3797IUKG#PBF acts as triple-channel LED current controller with per-channel PWM dimming and open-LED fault detection. Use Value: Enables real-time color mixing and adaptive beam patterns while maintaining ASIL-B–compatible fault reporting via FLT1–3. |
Use Scenario: High-brightness theatrical lighting fixtures requiring precise color point stability across wide ambient temperature ranges. IC Role / Device Role / Timing Role: LT3797IUKG#PBF regulates current in each RGB string with independent thermal derating via CTRL1–3 and SS1–3. Use Value: Maintains chromaticity within Δu'v' < 0.003 over –40°C to +125°C via rail-to-rail ISP/ISN sensing and 1.25V FBH reference stability. |
| Large-Screen Digital Billboards | Industrial Machine Vision Illumination |
Use Scenario: Outdoor LED video walls exposed to 60V automotive battery transients and wide temperature swings. IC Role / Device Role / Timing Role: LT3797IUKG#PBF provides triple-channel constant-current drive with VIN transient ride-through and per-string open-LED protection. Use Value: Ensures uninterrupted operation during load-dump events; FLT1–3 flags failed strings for predictive maintenance without display blackout. |
Use Scenario: High-speed inspection systems requiring strobed, uniform illumination synchronized to camera exposure. IC Role / Device Role / Timing Role: LT3797IUKG#PBF delivers sub-microsecond PWM edge alignment across all three channels via SYNC input and matched GATE timing. Use Value: Achieves <10ns inter-channel PWM skew for pixel-perfect strobe timing; TG1–3 ensures zero leakage current during off-state. |
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 |
|---|---|---|---|
| LT3797EUKG#PBF | Same silicon, rated for 0°C to 125°C junction; lower guaranteed temp range than LT3797IUKG#PBF | Not qualified for automotive cold-cranking (–40°C startup); unsuitable for under-hood lighting | Select LT3797IUKG#PBF for designs requiring full –40°C to +125°C operation with production test coverage. |
| LT3761EFE#PBF | Single-channel boost LED controller; no TG drivers, no FBH-based CV mode, no per-channel FLT output | Lacks multi-string independence, open-LED protection per channel, and PMOS disconnect capability | Use only when driving one LED string with simpler fault requirements; not a functional substitute for triple-channel control. |
Compared with LT3797EUKG#PBF, the LT3797IUKG#PBF guarantees full –40°C to +125°C operation with production-tested parameters, while LT3761EFE#PBF lacks channel replication, fault isolation, and high-side sensing - making it unsuitable for RGB or fault-tolerant multi-string systems.
Availability
LT3797IUKG#PBF is available at Aetrix Electronics and suitable for automotive adaptive lighting, industrial machine vision illumination, large-format digital billboards, and RGB stage lighting requiring stable component supply across extended temperature and transient-voltage conditions.
Supply support for LT3797IUKG#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 LT3797IUKG#PBF belongs to Linear's LED controller product line, engineered specifically for high-reliability, multi-string LED systems demanding independent channel control, robust fault handling, and wide-input operation in automotive and industrial environments.
FAQ
What is the maximum input voltage transient tolerance for LT3797IUKG#PBF?
The LT3797IUKG#PBF supports VIN transients up to 60V with automatic shutdown. When VIN exceeds 41V (typical), the integrated INTVCC supply disables, all three channels shut down (GATE pins pulled low, TG pins driven high), and soft-start circuits reset - protecting downstream circuitry without latch-up.
How does LT3797IUKG#PBF implement open-LED protection per channel?
LT3797IUKG#PBF uses FBH1–3 pins to monitor |ISP–FBH| voltage. During open-LED conditions, |ISP–FBH| drops below the 1.25V regulation target; the error amplifier drives VC high, triggering TG1–3 to disconnect the LED string. Simultaneously, FLT1–3 asserts low to signal the fault - all without affecting other channels.
Can LT3797IUKG#PBF operate in buck topology for all three channels?
Yes - LT3797IUKG#PBF supports buck, boost, buck-boost, SEPIC, and flyback topologies per channel. Its high-side ISP/ISN sensing and FBH-referenced feedback allow buck configurations without ground-referenced current sense limitations, enabling direct low-side LED cathode control.
What is the function of the TG1–3 pins on LT3797IUKG#PBF?
TG1–3 are level-shifted gate drivers for external P-channel MOSFETs. Each outputs an inverted PWM signal referenced to ISP (not GND), enabling safe LED string disconnection at up to ISP – 6.5V. They activate during idle mode, fault conditions, or analog dimming below 150mV CTRL voltage - ensuring zero current leakage.
Does LT3797IUKG#PBF require external compensation components per channel?
Yes - LT3797IUKG#PBF requires external RC networks from VC1–3 to GND for loop compensation. Each VC pin connects to the error amplifier output; the RC values set phase margin and bandwidth per channel. No shared compensation is allowed - independent tuning ensures optimal stability across mixed topologies.
LT3797IUKG#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)
LT3797IUKG#PBF FAQ
1.How can I place an order for LT3797IUKG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3797IUKG#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 LT3797IUKG#PBF reliable?
The price and inventory of LT3797IUKG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3797IUKG#PBF is usually 5 days.
3.What payment methods are accepted for LT3797IUKG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3797IUKG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3797IUKG#PBF?
LT3797IUKG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3797IUKG#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 LT3797IUKG#PBF?
For technical support, including LT3797IUKG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3797IUKG#PBF requirements.
6.How does Aetrix verify that LT3797IUKG#PBF is sourced from the original manufacturer or authorized distributors?
All LT3797IUKG#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 LT3797IUKG#PBF meets industry standards.
7.What is the process for return or replacement of LT3797IUKG#PBF?
All LT3797IUKG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3797IUKG#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 LT3797IUKG#PBF part is unused and in its original packaging.
Return procedure for LT3797IUKG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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