My Inquiry
My Account
Analog Devices Inc. LT3965IFE#TRPBF
- Part No.:
- LT3965IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3965IFE#TRPBF.pdf
- Description:
- IC LED DRVR RGLTR I2C 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,443
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3965IFE#TRPBF from Analog Devices is an 8-channel I²C-controlled LED bypass switch IC for precision dimming of individual LEDs in high-voltage strings using a common current source. It integrates eight floating-source 17V/330mΩ NMOS switches, supports 256:1 digital PWM dimming with optional logarithmic fade transition, and reports open/shorted LED faults per channel. It is used in automotive LED headlight clusters requiring AEC-Q100-compliant fault-aware dimming control.
For engineers reviewing the LT3965IFE#TRPBF datasheet, LT3965IFE#TRPBF pinout, LT3965IFE#TRPBF application, or LT3965IFE#TRPBF equivalent, key selection considerations include its 8-channel independent fade-capable PWM control, programmable VOTH/VSTH thresholds (4.5–18V open, 1–13.7V shorted), 28-lead TSSOP package with exposed GND pad, and AEC-Q100 Grade I (–40°C to +125°C) qualification.
Technical Context
The LT3965IFE#TRPBF implements a distributed LED string architecture where each of eight NMOS switches operates as a floating-source bypass element-drain tied to LED+ node, source referenced to local segment return-enabling selective current rerouting around individual LEDs. Its fault detection logic independently monitors DRN–SRC voltage per channel against four user-programmable open-LED thresholds (VOTH[1:0]) and four shorted-LED thresholds (VSTH[1:0]), with LEDREF pin enabling dynamic scaling of short-detection levels.
Dimming is executed via an internal 2048-cycle PWM counter synchronized to either an on-chip oscillator (programmed by RTCLK resistor) or external clock; fade transitions use 11-bit logarithmic interpolation between 8-bit dimming endpoints, ensuring perceptually smooth brightness changes without microcontroller intervention. The I²C interface supports multidrop operation (16 devices) via four address pins and includes dedicated ALERT output for interrupt-driven fault handling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 8V to 60V - supports high-side LED strings powered by buck or boost LED drivers up to 60V bus voltage. |
| Switch On-Resistance | 330 mΩ max - ensures low conduction loss and minimal self-heating during bypass operation at ≥500mA channel current. |
| PWM Dimming Resolution | 256:1 (8-bit) - enables precise luminance control from 0.39% to 100% duty cycle in discrete steps. |
| Fade Transition Resolution | 11-bit logarithmic interpolation - delivers perceptually uniform brightness ramps between dimming states, avoiding visible stepping. |
| Open LED Threshold Options | 4.5V / 9V / 13.5V / 18V - selectable per channel to match expected LED forward voltage drop under fault conditions. |
| Shorted LED Threshold Options | 1V to 13.7V (scalable via LEDREF) - allows detection of single- or multi-LED shorts across varied string configurations. |
| Operating Temperature | –40°C to +125°C - qualified per AEC-Q100 Grade I for under-hood automotive lighting applications. |
| I²C Address Space | 16 unique addresses - enables daisy-chained control of multiple LT3965IFE#TRPBF devices on a single bus without address conflict. |
Pinout & Package
LT3965IFE#TRPBF is housed in a 28-lead plastic TSSOP package (FE) with exposed thermal pad (Pin 29) that must be soldered to PCB ground for thermal and electrical integrity. Package thermal resistance θJC = 10°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | High-voltage supply input | Power source for all eight NMOS switches and fault detectors; must exceed SRC voltage by ≥7.1V for proper bypass operation. |
| EN/UVLO | Enable and undervoltage lockout input | 1.24V falling threshold with programmable hysteresis; controls device power-up/reset and disables switches when VIN–SRC falls below safe margin. |
| ALERT | Open-drain fault indicator output | Asserts low on open LED, shorted LED, or overtemperature fault; supports I²C alert response address (ARA) for multi-device systems. |
| RTCLK | Oscillator programming / external clock input | Configures internal PWM frequency (via resistor to GND) or accepts external clock (2.5MHz max); dimming frequency = input / 2048. |
| LEDREF | Reference voltage for shorted-LED detection | Sets baseline for VSTH thresholds; applying 0–4V scales short-detection level linearly (e.g., 3V → 1–10.4V range). |
| VDD | Logic supply and I²C reference | 2.7–5.5V supply for I²C interface and internal logic; defines SCL/SDA voltage levels and enables serial communication even in shutdown. |
| SCL / SDA | I²C clock and bidirectional data | Standard 400kHz I²C interface with VDD-referenced thresholds; supports random register access and multidrop addressing. |
| ADDR[4:1] | Hardware I²C address select inputs | Four pins configure 16 unique slave addresses; internally pulled up to VDD (500kΩ), allowing simple ground ties for address assignment. |
| DRN[8:1] | Drain terminals of NMOS switches | Floating high-side connections to LED string segments; require 100kΩ pull-up to VDD if unused. |
| SRC[8:1] | Source terminals of NMOS switches | Floating low-side connections to LED segment returns; must be ≤VIN – 7.1V; tie to GND if unused. |
| GND (Pin 29) | Thermal and signal ground | Exposed pad; mandatory connection to PCB ground plane for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Eight independent floating-source NMOS switches | Enables per-LED bypass in series strings without shared cathode/anode constraints-supports mixed-VF LEDs and modular string reconfiguration. |
| Programmable open/short LED fault detection | Per-channel VOTH/VSTH thresholds eliminate false triggers in varying temperature and aging conditions; fault reporting via dedicated ALERT pin reduces MCU polling overhead. |
| Logarithmic fade transition with 11-bit interpolation | Matches human eye's nonlinear brightness perception-eliminates visible flicker or jumpiness during dimming changes in automotive ambient lighting. |
| AEC-Q100 Grade I qualification | Validated for automotive under-hood environments including thermal cycling, vibration, and ESD robustness-enables direct integration into headlight ECU designs. |
| I²C multidrop support with 16-address capability | Reduces wiring complexity and MCU GPIO count in large-area displays or multi-zone lighting systems-no external address decoders required. |
| Internal oscillator + external clock option | Provides design flexibility: resistor-programmed timing eliminates need for external clock source, while external drive enables synchronization across multiple LED drivers. |
Applications
| Automotive LED Headlight Clusters | Large LED Displays |
|---|---|
Use Scenario: Adaptive driving beam (ADB) systems requiring independent pixel-level dimming of 8+ LED segments within a single headlight module. IC Role / Device Role / Timing Role: Bypass switch controller managing current path around individual LEDs to shape light distribution; fault detection ensures fail-safe beam pattern maintenance. Use Value: Enables ISO 11270-compliant glare-free ADB without adding high-side current sources per segment-reduces BOM cost and PCB area vs. multi-channel constant-current drivers. | Use Scenario: Outdoor video billboard with >1000 RGB LED modules, each containing 4-series LEDs per color channel. IC Role / Device Role / Timing Role: Per-module LED string bypass controller enabling grayscale control and open-circuit redundancy across thousands of nodes. Use Value: Supports hot-swap repair and predictive maintenance via per-channel open/short reporting-minimizes display downtime and service labor costs. |
| Automated Camera Flash Equipment | RGBW Color Mixing Lighting |
Use Scenario: High-speed industrial inspection system using synchronized strobed flash with adjustable intensity per LED row. IC Role / Device Role / Timing Role: Precision PWM dimmer synchronizing flash timing across 8 parallel LED banks; fade transition prevents mechanical shutter interference. Use Value: Achieves sub-microsecond dimming step accuracy and jitter-free triggering-critical for motion-blur-free imaging at >10k fps. | Use Scenario: Architectural cove lighting with tunable white (2700K–6500K) and saturated color rendering using 4-channel (R/G/B/W) LED strings. IC Role / Device Role / Timing Role: Independent dimming engine for each color channel, maintaining chromaticity stability during CCT adjustment via coordinated fade curves. Use Value: Eliminates color shift during warm-to-cool transitions by synchronizing logarithmic fades across R/G/B/W-meets ENERGY STAR Lamps V2.1 color consistency requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED bypass switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3965EFE#TRPBF | Same silicon, extended temperature grade (–40°C to +125°C) but non-AEC-Q100 qualified; identical pinout, registers, and electrical specs. | Targeted at industrial or commercial LED systems without automotive reliability certification requirements. | Select when AEC-Q100 compliance is not mandated and cost sensitivity favors standard-grade variant. |
| MAX20052ATP/V+T | 8-channel automotive LED controller with integrated boost converter; lacks independent fade transition and has fixed 5.5V VIN max vs. LT3965IFE#TRPBF's 60V capability. | Designed for low-voltage interior lighting; cannot replace LT3965IFE#TRPBF in high-VIN headlight or display backlights. | Choose only for space-constrained interior modules where integrated power conversion outweighs flexibility trade-offs. |
Compared with LT3965EFE#TRPBF, the LT3965IFE#TRPBF adds AEC-Q100 qualification for automotive use without sacrificing performance; versus MAX20052ATP/V+T, it offers higher VIN tolerance and true per-channel fade control but requires external LED driver-making it optimal for high-reliability, high-voltage, and perceptually critical dimming systems.
Availability
LT3965IFE#TRPBF is available at Aetrix Electronics and suitable for automotive LED headlight clusters, large-format LED displays, and automated camera flash equipment requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for LT3965IFE#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 industrial, automotive, communications, and healthcare markets.
The LT3965IFE#TRPBF belongs to Analog Devices' Power by Linear™ LED driver portfolio, engineered specifically for fault-resilient, high-voltage LED string control in safety-critical automotive and professional lighting systems.
FAQ
What is the default power-on state of the LT3965IFE#TRPBF switches?
The LT3965IFE#TRPBF initializes all eight NMOS switches in the OFF state (open circuit) upon power-on reset, resulting in full LED string conduction-meaning all LEDs are illuminated by default. This behavior distinguishes it from the LT3965-1 variant, which powers up with all switches ON (LEDs off). The default state is defined in the POR register map and can be overridden immediately via I²C command after EN/UVLO assertion.
Does the LT3965IFE#TRPBF support synchronization of PWM dimming across multiple devices?
Yes, the LT3965IFE#TRPBF supports inter-device PWM synchronization via its RTCLK pin: driving RTCLK with a common external clock signal (≤2.5MHz) forces all connected devices to derive their 2048-cycle dimming period from the same source, eliminating phase drift. This is essential for flicker-free operation in multi-module lighting systems and is explicitly validated in the datasheet's timing diagrams and typical performance curves.
How does the LT3965IFE#TRPBF handle an open LED fault condition?
When an open LED fault is detected-i.e., DRN–SRC voltage exceeds the programmed VOTH threshold-the LT3965IFE#TRPBF automatically turns ON the corresponding NMOS switch to bypass the faulty LED, maintaining string continuity and preventing overvoltage damage. Simultaneously, it asserts the ALERT pin low and sets the relevant bit in the Open LED Fault Register (OLFREG); the condition persists until cleared by I²C write or power cycle.
Can the LT3965IFE#TRPBF drive LEDs directly, or does it require an external current source?
The LT3965IFE#TRPBF does not provide current regulation and must be used with an external constant-current LED driver (e.g., LT3955, LT3761, or similar buck/boost LED controller). Its role is purely switching: routing current around selected LEDs in a string supplied by that driver. This architecture enables high-efficiency, high-VIN operation unattainable with integrated-current solutions.
What is the purpose of the LEDREF pin on the LT3965IFE#TRPBF?
The LEDREF pin on the LT3965IFE#TRPBF sets the reference voltage for programmable shorted-LED detection: VSTH thresholds scale linearly with LEDREF (e.g., VSTH = 1V, VLEDREF+1V, 2×VLEDREF+1V, or 3×VLEDREF+1V). Applying 0V fixes VSTH at 1V; applying 3V yields thresholds of 1V, 4V, 7V, and 10V-allowing precise matching to actual LED string configuration and forward voltage tolerances.
LT3965IFE#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 Regulator
- Topology:
- Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 8
- Voltage - Supply (Min):
- 8V
- Voltage - Supply (Max):
- 60V
- Voltage - Output:
- -
- Current - Output / Channel:
- 500mA
- Frequency:
- -
- Dimming:
- I2C, PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3965IFE#TRPBF FAQ
1.How can I place an order for LT3965IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3965IFE#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 LT3965IFE#TRPBF reliable?
The price and inventory of LT3965IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3965IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3965IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3965IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3965IFE#TRPBF?
LT3965IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3965IFE#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 LT3965IFE#TRPBF?
For technical support, including LT3965IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3965IFE#TRPBF requirements.
6.How does Aetrix verify that LT3965IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3965IFE#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 LT3965IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3965IFE#TRPBF?
All LT3965IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3965IFE#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 LT3965IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3965IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3965IFE#TRPBF Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
