IC manufacturers Analog Devices

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Analog Devices LT3922-1

36V, 2.3A Synchronous Step-Up LED Driver with 25,000:1 PWM Dimming

Overview

TopologyBuck Converter
Input voltage20-36 V
Switching frequency200-2000 kHz
Output 115 V / 1 A

Description

The LTR3922-1 is a monolithic, synchronous, step-up 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. The LT3922-1 will maintain ±2% current regulation through an external sense resistor over a wide range of output voltages.The switching frequency is programmable from 200kHz to 2MHz by an external resistor at the RT pin or by an external clock applied at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. The LT3922-1 also includes a driver for an external high side PMOS for PWM dimming and an internal PWM signal generator for analog control of PWM dimming. When an external signal is available, the LT3922-1 can perform 25,000:1 PWM dimming with 100Hz PWM pulses.Additional features include an accurate external reference voltage for use with the CTRL and PWM pins, 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.

Features

  • ±2% LED Current Regulation
  • ±2% Output Voltage Regulation
  • 25,000:1 PWM Dimming at 100Hz
  • 128:1 Internal PWM Dimming
  • Spread Spectrum Frequency Modulation
  • Silent Switcher® Architecture for Low EMI
  • Operates in Boost, Buck Mode and Buck-Boost Mode
  • 2.8V to 36V Input Voltage Range
  • Up to 34V LED String Voltage
  • 2.3A, 40V Internal Switches
  • 200kHz to 2MHz Switching Frequency with SYNC
  • Analog or Duty Cycle LED Current Control
  • Open/Short LED Protection and Fault Indication
  • Thermally Enhanced 28-Lead (4mm × 5mm) QFN

Typical applications

  • Machine Vision
  • Automotive and Industrial Lighting

More information

Products

Order Code Data­sheet Simu­lation Downloads Status Product seriesL
(µH)
IRP,40K
(A)
ISAT,10%
(A)
ISAT,30%
(A)
RDC max.
(mΩ)
fres
(MHz)
Mount Samples
74437324047SPEC

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.

8 files Active i| Production is active. Expected lifetime: >10 years.WE-LHMI SMT Power Inductor 4.7 2.95 2.45 5.4 105 31 SMT
Order Code Data­sheet Simu­lation
74437324047SPEC

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.

Samples
Order Code Data­sheet Simu­lation Downloads Status Product seriesL
(µH)
IRP,40K
(A)
ISAT,10%
(A)
ISAT,30%
(A)
RDC max.
(mΩ)
fres
(MHz)
Mount Samples