DescripTion
The LT®3990 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 62V, and consumes only 2.5µA of quiescent current. A high efficiency switch is included on the die along with the catch diode, boost diode, and the neces sary oscillator, control and logic circuitry. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping the output ripple below 5mV in a typical application. Current mode topology is used for fast transient response and good loop stability. A catch diode current limit provides protection against shorted outputs and overvoltage conditions. An accurate programmable undervoltage lockout feature is available, producing a low shutdown current of 0.7µA. A power good flag signals when VOUT reaches 90% of the programmed output voltage. The
LT3990 is available in small, thermally enhanced 16-pin MSOP and 3mm × 3mm DFN packages.

FEATUREs
Low Ripple Burst Mode® Operation
   2.5µA IQ at 12VIN to 3.3VOUT
   Output Ripple < 5mVP-P
Wide Input Voltage Range: 4.2V to 62V Operating
Adjustable Switching Frequency: 200kHz to 2.2MHz
Integrated Boost and Catch Diodes
350mA Output Current
Accurate Programmable Undervoltage Lockout
FMEA Fault Tolerant (MSOP Package)
   Output Stays at or Below Regulation Voltage During
   Adjacent Pin Short or When a Pin is Left Floating
Low Shutdown Current: IQ = 0.7µA
Internal Sense Limits Catch Diode Current
Power Good Flag
Small, Thermally Enhanced 16-Pin MSOP and (3mm × 3mm) DFN Packages

APPLICATIONs
Automotive Battery Regulation
Power for Portable Products
Industrial Supplies