LT3999 Datasheet

• 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
• ΔV_IN 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
• 10-Lead MSOP and DFN Packages

• 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

The LT3999 is a monolithic, high voltage, high frequency DC/DC transformer driver providing isolated power in a small solution footprint.

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 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 MSOP and 3mm × 3mm DFN package with exposed pad.