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reference designLT8355-1

Analog Devices LT8355-1

60VIN/120VOUT Dual LED Controller with Exponential PWM and Scalable Dimming

Overview

TopologyBuck Converter
Input voltage36-54 V
Switching frequency100-2000 kHz
Output 1120 V

Description

The LT®8355-1 a dual-channel DC/DC controller designed to drive two strings of high current LEDs. The fixed frequency, current mode architecture results in stable operation over a wide range of supply and output voltages. Voltage feedback pins serve as the inputs for several LED protection features and makes it possible for the converters to operate as a constant-voltage sources.The LT8355-1 senses output current at the high or low side of the load. The product of CTRL2 and IADJ2 inputs provides analog programming of the output current for channel 2. Channel 1 output current is programmed through CTRL1 input. The PWM input and PWMTG high side PMOS driver provides precision time-based LED dimming capability. When driven by an external digital signal, the PWM input provides LED dimming ratios of up to 20,000:1 at 100Hz. When driven by a constant voltage, the PWM input selects from one of 128 internally generated, precision, exponentially spaced dimming ratios ranging from 0.78% up to 100%.

Features

  • Two independent High Voltage LED DriverControllers Channels
  • 128:1 Internal Exponential PWM Dimming
  • Two-Pin Multiplying Analog Dimming (CH2)
  • Spread Spectrum Frequency Modulation
  • 20,000:1 External PWM Dimming at 100Hz
  • Rail-to-Rail LED Current Sensing: 0V to 120V
  • ±2% LED Current Regulation
  • ±2% Output Voltage Regulation
  • LED Short/Open Protection and Indication
  • Wide Input Voltage Range (5V to 60V)
  • PMOS Switch Driver for PWM and Output Disconnect
  • Independent Channel Dimming
  • Constant-Voltage and Constant-Current Regulation
  • Adjustable Switching Frequency 100kHz to 2MHz
  • Independent OPEN/SHORT LED FAULT per channel
  • Programmable VIN UVLO with Hysteresis
  • Side Solderable 28-Lead 4mm × 5mm QFN Package
  • AEC-Q100 Qualified for Automotive Applications

Typical applications

  • Automotive Head Lamps/Running Lamps, Accurate Current Limited Voltage Regulator
  • High Voltage LED Applications

More information

Products

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L(µH)
IRP,40K(A)
RDC max.(mΩ)
fres(MHz)
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7447789133
SPECWE-PD SMT Power Inductor, 33 µH, 1.85 A
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Status Activei| Production is active. Expected lifetime: >10 years.
Product seriesWE-PD SMT Power Inductor
Inductance33 µH
Performance Rated Current1.85 A
DC Resistance240 mΩ
Self Resonant Frequency16 MHz
Size7332 
VersionRobust 
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