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Analog Devices Inc. LT8391AIUFD#TRPBF
- Part No.:
- LT8391AIUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT8391AIUFD#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,154
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Product details
Overview
LT8391AIUFD#TRPBF from Analog Devices is a synchronous 4-switch buck-boost LED controller IC designed for high-frequency, wide-input-output LED current regulation in automotive and industrial lighting. It operates from 4V to 60V input and delivers 0V to 60V output with ±3% LED current accuracy, 2MHz switching capability, and seamless region transitions-enabling stable drive of 16V/1.5A LED strings in headlamp systems.
For engineers reviewing the LT8391AIUFD#TRPBF datasheet, LT8391AIUFD#TRPBF pinout, LT8391AIUFD#TRPBF application, or LT8391AIUFD#TRPBF equivalent, key selection criteria include its AEC-Q100 qualification, 28-pin QFN (4mm × 5mm) package with exposed pad, integrated peak-buck/peak-boost current mode control, and dual analog/PWM dimming support for flicker-free operation.
Technical Context
The LT8391AIUFD#TRPBF implements a proprietary peak-buck/peak-boost current mode architecture that uses a single inductor and shared current sense resistor (LSP/LSN) to maintain continuous conduction across buck, buck-boost, and boost regions. Its internal oscillator supports adjustable 600kHz–2MHz fixed frequency or triangle spread-spectrum modulation via SYNC/SPRD pin.
It integrates dual gate drivers (TG1/BG1/TG2/BG2), a 5V INTVCC LDO, 2V VREF reference, and fault detection circuitry for open/short LED conditions-with FAULT reporting latched or hiccup-mode configurable via SS pin resistor network.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 60V - supports 12V/24V/48V battery systems and transient ride-through up to 56V. |
| Output Voltage Range | 0V to 60V - enables direct drive of multi-LED strings without external voltage translation. |
| Switching Frequency | 600kHz to 2MHz - allows compact magnetics and EMI optimization; synchronizable or spread-spectrum enabled. |
| LED Current Accuracy | ±3% at 100mV full scale - ensures consistent luminance across temperature and unit-to-unit variation. |
| PWM Dimming Ratio | Up to 2000:1 external, 128:1 internal - meets stringent automotive flicker requirements down to 0.05% duty cycle. |
| Analog Dimming Range | 20:1 via CTRL1/CTRL2 - provides smooth brightness control with ±3% linearity over full range. |
| Operating Temp Range | –40°C to +125°C junction - qualified for under-hood automotive environments per AEC-Q100 Grade I. |
Pinout & Package
LT8391AIUFD#TRPBF is housed in a 28-lead plastic QFN package (4mm × 5mm) with exposed thermal pad (Pin 29 = GND), θJA = 43°C/W, θJC = 3.4°C/W. The exposed pad must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP / ISN | LED current sense differential inputs | Kelvin-connected to RLED; enable precise ±3% current regulation and open/short LED fault detection. |
| LSP / LSN | Inductor current sense differential inputs | Shared sense path for peak-buck/peak-boost control; supports seamless region transition without discontinuity. |
| TG1 / BG1 / TG2 / BG2 | N-channel MOSFET gate drivers | Drive external 4-switch power stage; TG1/BG1 for buck side, TG2/BG2 for boost side with bootstrap supplies (BST1/BST2). |
| PWMTG | High-side PMOS PWM switch driver | Inverted buffered PWM output referenced to VOUT; drives external PMOS for high-side LED dimming with <100ns propagation delay. |
| CTRL1 / CTRL2 | Analog dimming and thermal derating inputs | Program LED current threshold linearly (0–100mV); CTRL2 supports NTC-based thermal foldback. |
| FAULT | Open-drain fault status output | Asserts low on open LED (VFB > 0.95V & VISP-ISN < 10mV) or short LED (VFB < 0.25V); latched or hiccup configurable. |
Key Features
| Feature | Design Value |
|---|---|
| Proprietary peak-buck/peak-boost control | Eliminates audible noise and current discontinuity during VIN/VOUT crossover; maintains <1% LED current ripple across all regions. |
| Flicker-free spread spectrum | 25% triangle modulation on internal oscillator reduces peak EMI by >10dB without compromising regulation stability. |
| AEC-Q100 Grade I qualification | Validated for automotive under-hood operation including HTOL, TC, and ESD testing per Rev H standards. |
| Integrated 5V INTVCC LDO | Supplies internal logic and gate drivers from VIN; 145mA current limit enables driving multiple external FETs without external bias supply. |
| Configurable fault response | SS pin resistor network selects hiccup (no resistor), latch-off (499kΩ), or keep-running (100kΩ) behavior during LED faults. |
Applications
| Automotive Head Lamps | Industrial High-Bay Lighting |
|---|---|
Use Scenario: Adaptive front-lighting system (AFS) requiring dynamic beam shaping and instant dimming across 12V–48V vehicle architectures. IC Role / Device Role / Timing Role: Primary LED current controller managing 4-switch buck-boost topology with real-time region transition and PWM dimming synchronization. Use Value: Enables 2MHz operation for compact 2.2µH inductor, ±3% current accuracy for consistent photometric output, and AEC-Q100 compliance for functional safety readiness. | Use Scenario: High-efficiency warehouse lighting powered from 24VDC or 48VDC PoE++ infrastructure with >100,000-hour lifetime requirement. IC Role / Device Role / Timing Role: Constant-current LED driver supporting wide input range and seamless dimming down to 0.05% via 2000:1 external PWM. Use Value: Delivers >94% efficiency at 2MHz, eliminates need for separate buck/boost converters, and supports thermal derating via CTRL2 for long-term lumen maintenance. |
| UV-C Disinfection Systems | Battery-Powered Emergency Lighting |
Use Scenario: Portable UV-C LED arrays operating from 12V Li-ion packs with strict EMI limits for medical-grade equipment. IC Role / Device Role / Timing Role: High-frequency LED driver enabling compact layout and spread-spectrum EMI suppression without external filters. Use Value: 25% triangle spread spectrum reduces conducted emissions below CISPR-11 Class B limits; 4V–60V input accommodates battery discharge curve. | Use Scenario: Self-contained emergency egress lighting with 72-hour backup runtime, requiring ultra-low quiescent current during standby. IC Role / Device Role / Timing Role: Low-IQ LED controller with 1µA shutdown current and programmable UVLO for battery protection. Use Value: Achieves <2µA VIN quiescent current in shutdown (VEN/UVLO < 0.3V), extends battery life while maintaining fast wake-up and soft-start sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8391AEUFD#TRPBF | Same silicon, –40°C to +125°C temp grade (Grade E), non-AEC-Q100 qualified. | Suitable for industrial/commercial lighting where automotive qualification is not required. | Select when AEC-Q100 is unnecessary and cost sensitivity favors Grade E. |
| LT8390AIUFD#TRPBF | Predecessor with 1MHz max switching, no spread spectrum, lower efficiency at 2MHz, same pinout and feature set otherwise. | Limited to lower-frequency designs; lacks SSFM for stringent EMI environments. | Choose only if legacy design reuse is prioritized over EMI performance and 2MHz capability. |
Compared with LT8391AEUFD#TRPBF, the LT8391AIUFD#TRPBF adds AEC-Q100 qualification and tighter parametric guarantees over temperature; versus LT8390AIUFD#TRPBF, it delivers 2MHz operation, spread-spectrum EMI reduction, and improved region-transition smoothness-making it optimal for next-gen automotive and high-density lighting.
Availability
LT8391AIUFD#TRPBF is available at Aetrix Electronics and suitable for automotive headlamps, industrial high-bay lighting, and battery-powered emergency lighting requiring stable component supply, AEC-Q100 compliance, and high-frequency LED control.
Supply support for LT8391AIUFD#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, Inc. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies.
The LT8391A product line delivers high-efficiency, wide-input-output LED controllers optimized for automotive lighting, industrial illumination, and portable UV systems-designed to replace discrete buck/boost solutions with integrated 4-switch architecture and robust fault management.
FAQ
What is the maximum switching frequency supported by the LT8391AIUFD#TRPBF?
The LT8391AIUFD#TRPBF supports an adjustable switching frequency range from 600kHz to 2MHz using the RT pin resistor. At RT = 59.0kΩ, the typical frequency is 2MHz - enabling compact magnetic design and reduced output ripple. Frequency synchronization and triangle spread-spectrum modulation are also supported via the SYNC/SPRD pin.
Does the LT8391AIUFD#TRPBF require external MOSFETs, and what types are needed?
Yes, the LT8391AIUFD#TRPBF is a controller IC and requires four external N-channel MOSFETs: two for the buck side (driven by TG1/BG1) and two for the boost side (driven by TG2/BG2). It does not integrate power switches. Bootstrap capacitors must be used with BST1 and BST2 pins to support high-side gate drive.
How does the LT8391AIUFD#TRPBF handle LED open-circuit and short-circuit faults?
The LT8391AIUFD#TRPBF detects open LED conditions when VFB > 0.95V and VISP-ISN < 10mV, and short LED conditions when VFB < 0.25V. Upon detection, it asserts the open-drain FAULT pin low and enters user-configurable behavior - hiccup, latch-off, or keep-running - selected by the resistor value on the SS pin.
Can the LT8391AIUFD#TRPBF drive a high-side PMOS for PWM dimming, and how is it implemented?
Yes, the LT8391AIUFD#TRPBF includes a dedicated PWMTG pin that provides a buffered, inverted PWM signal referenced to VOUT. It drives external high-side PMOS switches with rail-to-rail swing (VOUT to VOUT–5V), supporting fast turn-on/turn-off (<100ns propagation delay) and eliminating refresh noise in buck or boost modes.
Is the LT8391AIUFD#TRPBF pin-compatible with earlier versions like the LT8390A?
No, the LT8391AIUFD#TRPBF is not pin-compatible with the LT8390A. While both share the same 28-pin QFN package and many functional pins, the LT8391A introduces updated internal logic, revised timing characteristics, and additional features (e.g., spread-spectrum control, enhanced fault reporting) that require validation of layout and BOM changes before substitution.
LT8391AIUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 4V
- Voltage - Supply (Max):
- 60V
- Voltage - Output:
- 60V
- Current - Output / Channel:
- -
- Frequency:
- 600kHz ~ 2MHz
- Dimming:
- Analog, PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT8391AIUFD#TRPBF FAQ
1.How can I place an order for LT8391AIUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8391AIUFD#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 LT8391AIUFD#TRPBF reliable?
The price and inventory of LT8391AIUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8391AIUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8391AIUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8391AIUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8391AIUFD#TRPBF?
LT8391AIUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8391AIUFD#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 LT8391AIUFD#TRPBF?
For technical support, including LT8391AIUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8391AIUFD#TRPBF requirements.
6.How does Aetrix verify that LT8391AIUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8391AIUFD#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 LT8391AIUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8391AIUFD#TRPBF?
All LT8391AIUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8391AIUFD#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 LT8391AIUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT8391AIUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT8391AIUFD#TRPBF Tags
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BCR420UE6433HTMA1
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HV9910CLG-G
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