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Analog Devices Inc. LT8391AHFE#TRPBF
- Part No.:
- LT8391AHFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT8391AHFE#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,552
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Product details
Overview
LT8391AHFE#TRPBF from Analog Devices is a synchronous 4-switch buck-boost LED controller IC designed for high-frequency, wide-input/output LED driver applications. It operates from 4V to 60V input and delivers 0V to 60V output with ±3% LED current accuracy, 2000:1 external PWM dimming, and seamless region transitions-enabling automotive headlamps, industrial lighting, and battery-powered systems requiring stable current regulation across VIN/VOUT crossover.
For engineers reviewing the LT8391AHFE#TRPBF datasheet, LT8391AHFE#TRPBF pinout, LT8391AHFE#TRPBF application, or LT8391AHFE#TRPBF equivalent, key selection criteria include its AEC-Q100 qualified –40°C to 150°C junction temperature rating, 28-lead TSSOP package with exposed pad, 600kHz–2MHz adjustable switching frequency, and integrated fault reporting for open/short LED conditions.
Technical Context
The LT8391AHFE#TRPBF implements a proprietary peak-buck/peak-boost current mode control architecture that uses a single inductor and dual current sense paths (LSP/LSN for buck-side, ISP/ISN for LED-side) to maintain continuous conduction and low-noise transitions between buck, buck-boost, and boost operating regions. Its dual error amplifiers (EA1 for LED current, EA2 for output voltage) enable independent regulation loops with VC pin compensation and FB-based overvoltage/open/short LED protection.
It integrates two independent gate drivers (TG1/BG1 for buck side; TG2/BG2 for boost side), internal 5V INTVCC LDO, 2V VREF reference, and programmable soft-start via SS pin. The SYNC/SPRD pin supports either external clock synchronization or 25% triangle spread-spectrum modulation to reduce EMI without compromising efficiency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 60V - supports 12V/24V/48V automotive and industrial rails, including cold-crank transients up to 56V. |
| Output Voltage Range | 0V to 60V - enables direct drive of multi-string LED arrays up to 51V forward voltage without external boost stages. |
| Switching Frequency | 600kHz to 2MHz - adjustable via RT resistor; allows optimization of size vs. efficiency and EMI compliance in space-constrained designs. |
| LED Current Accuracy | ±3% at 100mV full scale - ensures consistent luminance across temperature and unit-to-unit variation in high-reliability lighting. |
| PWM Dimming Ratio | 2000:1 external, 128:1 internal - enables flicker-free dimming down to 0.05% duty cycle for architectural and automotive adaptive lighting. |
| Operating Junction Temp | –40°C to +150°C - qualified per AEC-Q100 Grade H; suitable for under-hood and high-ambient industrial environments. |
| Fault Protection | Open LED (VFB > 0.95V & V(ISP-ISN) < 10mV), short LED (VFB < 0.25V), latch-off/hiccup/keep-running modes - configurable via SS pin resistor. |
Pinout & Package
LT8391AHFE#TRPBF is housed in a 28-lead plastic TSSOP package with exposed thermal pad (Pin 29 = GND), optimized for high-power LED driver thermal management. θJA = 30°C/W, θJC = 5°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP / ISN | LED current sense differential inputs | Kelvin-connected to RLED; enable ±3% LED current regulation and open/short detection via V(ISP-ISN) threshold monitoring. |
| LSP / LSN | Buck-side inductor current sense differential inputs | Kelvin-connected to RSENSE; provide primary current feedback for peak-buck/peak-boost mode control and reverse current limiting. |
| TG1 / BG1 / BST1 / SW1 | Buck-side NMOS gate drive network | Drive external N-channel MOSFETs in buck configuration; BST1 supplies floating gate bias for high-side TG1 via bootstrap capacitor. |
| TG2 / BG2 / BST2 / SW2 | Boost-side NMOS gate drive network | Drive external N-channel MOSFETs in boost configuration; BST2 supplies floating gate bias for high-side TG2. |
| PWMTG | Inverted PWM top-gate driver output | Drives external high-side PMOS switch with rail-to-rail swing (VOUT to VOUT–5V); eliminates refresh noise in buck/boost transitions. |
| CTRL1 / CTRL2 | Analog dimming and thermal derating inputs | Set LED current threshold (0–100mV) linearly; CTRL2 supports NTC-based thermal foldback for safe operation at 150°C junction. |
| FAULT | Open-drain fault status output | Pulled low during open/short LED faults; updated only during PWM high time; requires external pull-up for system-level fault signaling. |
Key Features
| Feature | Design Value |
|---|---|
| Proprietary peak-buck/peak-boost control | Enables single-inductor buck-boost operation with <1% output ripple and <10µs transition time between VIN/VOUT regions. |
| 25% triangle spread spectrum | Reduces peak EMI by >10dB at fundamental switching frequency without requiring external filters or layout changes. |
| High-side PMOS PWM switch driver (PWMTG) | Eliminates gate-refresh noise in buck/boost modes and supports >100kHz PWM dimming with <130ns propagation delay. |
| Configurable fault response | SS pin resistor selects hiccup (no resistor), latch-off (499kΩ), or keep-running (100kΩ) behavior during LED fault events. |
| AEC-Q100 Grade H qualification | Validated for automotive under-hood use with guaranteed operation from –40°C to +150°C junction temperature. |
Applications
| Automotive Head Lamps | Industrial High-Frequency Lighting |
|---|---|
Use Scenario: Adaptive driving beam (ADB) systems requiring precise, flicker-free LED current control across 6–16V battery variations and engine cranking transients. IC Role / Device Role / Timing Role: Primary LED current controller managing four external MOSFETs in 4-switch buck-boost topology with seamless VIN/VOUT crossover. Use Value: Maintains ±3% LED current accuracy and 2000:1 dimming ratio despite 4V–60V input swings, enabling dynamic beam shaping without visible intensity steps. | Use Scenario: Factory automation lighting with stringent EMI limits and need for rapid on/off cycling in machine vision setups. IC Role / Device Role / Timing Role: Synchronous buck-boost LED driver with 2MHz switching and spread-spectrum modulation to meet CISPR-25 Class 5 radiated emissions. Use Value: Achieves >94% efficiency at 2MHz while reducing peak EMI by 12dB, eliminating need for ferrite beads or shielding cans in compact enclosures. |
| Battery-Powered Emergency Lighting | UV-C Disinfection Systems |
Use Scenario: Portable medical or safety lighting powered by 12V–48V Li-ion packs with runtime optimization and thermal derating. IC Role / Device Role / Timing Role: LED current regulator with dual analog dimming inputs (CTRL1/CTRL2) enabling real-time brightness and temperature-based current foldback. Use Value: Extends battery life via 2MHz operation (reducing inductor size/cost) and prevents LED degradation via programmable thermal derating down to 0.25V threshold. | Use Scenario: Pulsed UV-C LED arrays requiring precise current pulses with fast turn-on/turn-off and no overshoot during duty-cycle changes. IC Role / Device Role / Timing Role: Constant-current controller with PWMTG-driven high-side PMOS switch delivering <130ns PWM edge fidelity and no gate-refresh artifacts. Use Value: Enables clean, repeatable 100ns–10ms UV pulses with <1% current deviation, critical for calibrated germicidal dose delivery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8391IFE#TRPBF | Same functionality but rated for –40°C to +125°C junction temperature; lacks AEC-Q100 qualification. | Suitable for industrial or commercial lighting where ambient temperature stays below 125°C. | Select when automotive qualification and 150°C operation are not required; lower cost alternative with identical pinout and features. |
| LT8390AIFE#TRPBF | 2-switch buck-boost controller (not 4-switch); max 40V output; no PWMTG driver; 1000:1 PWM dimming. | Limited to applications where VIN never exceeds VOUT or vice versa; no high-side PMOS support. | Choose only if topology simplification and reduced BOM count outweigh need for seamless crossover and flicker-free dimming. |
Compared with LT8391IFE#TRPBF, the LT8391AHFE#TRPBF adds AEC-Q100 qualification and extended 150°C operation for under-hood use, while LT8390AIFE#TRPBF sacrifices 4-switch flexibility and dimming fidelity for lower gate count and cost in fixed-ratio applications.
Availability
LT8391AHFE#TRPBF is available at Aetrix Electronics and suitable for automotive headlamp systems, industrial high-frequency lighting, and battery-powered emergency lighting requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT8391AHFE#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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, and automotive markets.
The LT8391A product line delivers high-efficiency, wide-input/output LED controllers with integrated fault protection and AEC-Q100 qualification-designed specifically for demanding automotive lighting and industrial solid-state illumination applications.
FAQ
What is the maximum operating junction temperature for the LT8391AHFE#TRPBF?
The LT8391AHFE#TRPBF is specified for continuous operation from –40°C to +150°C junction temperature and is AEC-Q100 qualified for Grade H automotive applications. This rating enables reliable use in under-hood environments and high-ambient industrial settings where thermal derating is critical. The device includes internal overtemperature protection that activates above 150°C to prevent permanent damage.
How does the LT8391AHFE#TRPBF handle transitions between buck, buck-boost, and boost modes?
The LT8391AHFE#TRPBF uses a proprietary peak-buck/peak-boost current mode control scheme that monitors VIN/VOUT ratios and seamlessly switches between operating regions with <10µs transition time and minimal output ripple. Transition thresholds are precisely defined: buck-to-buck-boost at VIN/VOUT = 1.25, buck-boost-to-boost at 0.75, and peak-buck-to-peak-boost at 1.00, ensuring stable LED current regulation across all input-output conditions.
Can the LT8391AHFE#TRPBF drive a high-side PMOS PWM switch directly?
Yes, the LT8391AHFE#TRPBF includes a dedicated PWMTG pin that provides a buffered, inverted version of the PWM input signal with rail-to-rail swing from (VOUT – 5V) to VOUT. This allows direct drive of external high-side PMOS switches without external level-shifting circuitry, eliminating gate-refresh noise and enabling clean, fast PWM edges with <130ns propagation delay and <10ns jitter.
What fault protection features does the LT8391AHFE#TRPBF provide for LED strings?
The LT8391AHFE#TRPBF provides comprehensive LED fault protection including open LED detection (VFB > 0.95V and V(ISP-ISN) < 10mV), short LED detection (VFB < 0.25V), and configurable response modes (hiccup, latch-off, or keep-running) set via an external resistor on the SS pin. Fault status is reported on the open-drain FAULT pin, updated only during PWM high time to avoid false triggering.
Is the LT8391AHFE#TRPBF pin-compatible with other variants in the LT8391A family?
Yes, the LT8391AHFE#TRPBF shares identical pinout, footprint, and electrical interface with all LT8391A variants in the 28-lead TSSOP package-including LT8391AEFE#TRPBF and LT8391AIFE#TRPBF-enabling drop-in replacement across temperature grades. All variants use the same PCB layout, external components, and firmware, differing only in guaranteed operating temperature range and qualification status.
LT8391AHFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) 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 ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT8391AHFE#TRPBF FAQ
1.How can I place an order for LT8391AHFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8391AHFE#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 LT8391AHFE#TRPBF reliable?
The price and inventory of LT8391AHFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8391AHFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8391AHFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8391AHFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8391AHFE#TRPBF?
LT8391AHFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8391AHFE#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 LT8391AHFE#TRPBF?
For technical support, including LT8391AHFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8391AHFE#TRPBF requirements.
6.How does Aetrix verify that LT8391AHFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8391AHFE#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 LT8391AHFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8391AHFE#TRPBF?
All LT8391AHFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8391AHFE#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 LT8391AHFE#TRPBF part is unused and in its original packaging.
Return procedure for LT8391AHFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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