Analog Devices Inc. LT3999 DC-DC Transformer Driver

Analog Devices Inc. LT3999 DC-DC Transformer Driver is a monolithic, high-voltage, high-frequency, push-pull DC-DC driver designed to provide isolated power in a small solution footprint. The LT3999 includes functions such as duty cycle control, soft start, and protection features such as overvoltage lockout (OVLO), undervoltage lockout (UVLO), and thermal shutdown. The LT3999 has two 1A current limited power switches that switch out of phase. The duty cycle is programmable to adjust the output voltage. The switching frequency is programmed up to 1MHz and can be synchronized to an external clock for more accurate placement of switcher harmonics. 

The input operating range of the LT3999 is programmed with the precision undervoltage and overvoltage lockouts. The supply current is reduced to less than 1μA during shutdown. A user-defined RC time constant provides an adjustable soft-start capability by limiting the inrush current at start-up.

The LT3999 is available in a 10-lead Micro Small Outline Package (MSOP) and a 10-pad Dual Flat No Lead (DFN) package with exposed pad. Both package options are RoHS compliant. 


  • Wide Input Operating Range: 2.7V to 36V
  • Dual 1A Switches with Programmable Current Limit
  • Programmable Switching Frequency: 50kHz to 1MHz
  • Frequency Synchronization Up to 1MHz
  • ΔVIN Compensation Using Duty Cycle Control
  • Low Noise Topology
  • Programmable Input Over and Undervoltage Lockout
  • Cross Conduction Prevention Circuitry
  • Programmable Soft-Start
  • Low Shutdown Current: <1μA
  • Package Options:
    • MSOP-10 (3mm x 3mm) 
    • DFN-10 (3mm x 3mm) 
  • RoHS Compliant


  • Low Noise Isolated Supplies
  • Medical Instrument and Safety
  • Distributed Power
  • Multiple Output Supplies
  • Positive-to-Negative Supplies
  • Noise Immunity in Data Acquisition, RS232 and RS485


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Block Diagram

Block Diagram - Analog Devices Inc. LT3999  DC-DC Transformer Driver

Typical Application Circuit

Application Circuit Diagram - Analog Devices Inc. LT3999  DC-DC Transformer Driver

Pin Designations

Mechanical Drawing - Analog Devices Inc. LT3999  DC-DC Transformer Driver
Gepubliceerd op: 2019-08-12 | Bijgewerkt op: 2022-03-10