Analog Devices Inc. LT3967EFE#PBF

Overview

LT3967EFE#PBF from Analog Devices is an 8-channel LED bypass switching IC for precision dimming of high-voltage LED strings using a common current source. It integrates eight independent 15V/110mΩ NMOS switches, supports I²C-controlled PWM dimming (100–1000 Hz), provides open/shorted LED fault detection per channel, and operates with VIN up to 60V - enabling use in automotive headlight clusters and large RGBW displays.

For engineers reviewing the LT3967EFE#PBF datasheet, LT3967EFE#PBF pinout, LT3967EFE#PBF application, or LT3967EFE#PBF equivalent, key selection criteria include per-channel programmable fade transition (11-bit exponential), CRC-8 protected I²C communication, thermally enhanced 28-lead TSSOP package with exposed GND pad, and dual-threshold LED fault reporting (VOTH/VSTH) with ALERT interrupt signaling.

Technical Context

The LT3967EFE#PBF implements a floating-source NMOS matrix architecture where each DRN–SRC pair forms an independently controllable bypass path across one or more series LEDs. Its internal 100–1000 Hz PWM generator (programmable via RTSYNC resistor) or external clock input enables precise dimming without requiring MCU PWM resources.

Fault management is hardware-accelerated: open LED detection thresholds (5.5–12.4 V) and shorted LED thresholds (0.85–4.4 V) are configurable per channel via I²C registers; overheat detection triggers at ≥170°C; all faults assert the open-drain ALERT pin and populate dedicated status registers. The watchdog timer (15–20 ms timeout) resets register state on I²C communication failure.

Key Specifications

Pinout & Package

LT3967EFE#PBF uses a thermally enhanced 28-lead plastic TSSOP (FE package) with exposed GND pad (Pin 29), θ_JA = 30°C/W. The package requires soldering the exposed pad directly to the PCB ground plane for optimal thermal performance and electrical stability.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED bypass switching applications.

Compared with LT3965EFE#PBF and TLC59284PWR, the LT3967EFE#PBF uniquely combines 8-channel floating-source switching, per-channel programmable fault thresholds, and 11-bit exponential fade - making it the only option for high-reliability, high-fidelity automotive and display applications demanding both flexibility and diagnostics.

Availability

LT3967EFE#PBF is available at Aetrix Electronics and suitable for automotive LED headlight clusters, large-format LED displays, and RGBW color-mixing lighting requiring stable component supply, long-term lifecycle assurance, and AEC-Q100-aligned reliability.

Supply support for LT3967EFE#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.

The LT3967EFE#PBF belongs to Analog Devices' LED lighting control product line, engineered specifically for high-voltage, fault-resilient LED string dimming in safety-critical and visually demanding applications such as adaptive headlights and broadcast-grade displays.

FAQ

What is the maximum LED string voltage the LT3967EFE#PBF can support?

The LT3967EFE#PBF supports LED strings up to 54 V, enabled by its 60 V absolute maximum VIN rating and 15 V maximum DRN–SRC differential voltage per channel. Each channel's 110 mΩ NMOS switch handles up to 1.3 A, allowing bypass of multiple series LEDs while maintaining safe operating area under thermal constraints.

Does the LT3967EFE#PBF require an external microcontroller to operate?

Yes, the LT3967EFE#PBF requires an external microcontroller for I²C configuration and real-time control. It does not execute autonomous dimming sequences - all channel states, fade parameters, fault thresholds, and PWM settings are written via I²C commands. However, once configured, it maintains dimming and fault response independently without MCU intervention.

How does the LT3967EFE#PBF handle open LED faults during operation?

When an open LED fault is detected (DRN–SRC voltage exceeds programmed VOTH), the LT3967EFE#PBF automatically turns on the corresponding NMOS switch to bypass the faulty LED, preserving string continuity. It asserts the ALERT pin and sets the relevant bit in the FAULT_STATUS register. PWM dimming for that channel halts until cleared via I²C write command.

Can the LT3967EFE#PBF be used with an external PWM clock source?

Yes, the LT3967EFE#PBF accepts an external clock signal on the RTSYNC pin (200–2000 kHz range). When driven above RTVIH (1.5 V) and below RTVIL (0.4 V), the external clock overrides the internal oscillator. The final PWM dimming frequency equals the external clock frequency divided by 2048 - enabling precise synchronization to camera frame rates or other system clocks.

What is the purpose of the WDI pin on the LT3967EFE#PBF?

The WDI (Watchdog Input) pin on the LT3967EFE#PBF sets the watchdog timeout period using a capacitor to GND (15–20 ms typical). If no valid I²C START–STOP sequence occurs within this window, the device resets all registers to their power-on defaults, restores switch states per ADDR[4:1] resistor configuration, and reverts PWM clock to the RTSYNC-programmed source - ensuring fail-safe recovery from communication lockups.