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reference designLT3935

Analog Devices LT3935

36V, 4A Synchronous Step-Down LED Driver with Silent Switcher

Overview

TopologyBuck Converter
Input voltage3.6-36 V
Switching frequency200-2000 kHz
Output 14 A

Description

The LT®3935 is a monolithic, synchronous, step-down DC/DC converter that utilizes fixed-frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analog voltage or the duty cycle of pulses at the CTRL pin. An output voltage limit can be set with a resistor divider to the FB pin.The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. Additional features include an LED current monitor, an accurate EN/UVLO pin threshold, open-drain fault reporting for open-circuit and short-circuit load conditions,and thermal shutdown. The LT3935 utilizes proprietary Silent Switcher technology for very low EMI.

Features

  • ±1.5% LED Current Regulation
  • ±1.2% Output Voltage Regulation
  • Spread-Spectrum Frequency Modulation
  • Silent Switcher® Architecture for Low EMI
  • 3.6V to 36V Input Voltage Range
  • 0V to 36V LED String Voltage
  • 200kHz to 2MHz with SYNC Function
  • 20:1 Analog or Duty Cycle LED Current Control
  • Open/Short LED Fault Indication
  • Accurate LED Current Sense with Monitor Output
  • Programmable UVLO
  • Thermally Enhanced 28-Lead (5mm × 4mm) LQFN

Typical applications

  • Industrial and General Purpose Lighting
  • Automotive Lighting

More information

Products

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Order Code
Data­sheet
Simu­lation
Downloads
Status
Product series
L(µH)
IRP,40K(A)
ISAT,30%(A)
RDC typ.(mΩ)
fres(MHz)
VOP(V)
Mount
SamplesAvailability & Sample
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74438357010
SPECWE-MAPI SMT Power Inductor, 1 µH, 10.25 A

PCN pending

Due to a pending PCN there will be a new datasheet revision issued for this order code soon. Please find the actual as well based on valid PCN date the new revision datasheet below. If you have further questions please get in contact with our sales staff.

Simu­lation
Availability
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Downloads10 files

Status Activei| Production is active. Expected lifetime: >10 years.
Product seriesWE-MAPI SMT Power Inductor
Inductance1 µH
Performance Rated Current10.25 A
Saturation Current @ 30%12.5 A
DC Resistance11.6 mΩ
Self Resonant Frequency59 MHz
Operating Voltage80 V
MountSMT 
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