Linear Technology announces the LT3999, a monolithic push-pull isolated DC/DC transformer driver with two 1 A current limited power switches. The LT3999 operates over an input voltage range of 2.7 V to 36 V, is targeted for power levels up to 15 W and can produce a wide range of output voltages. This makes it well suited for automotive, industrial, medical and military applications.
The programmable duty cycle and turns ratio of the transformer sets the output voltage. Several off-the-shelf transformers shown in the data sheet simplify the design. The switching frequency is adjustable from 50 kHz to 1 MHz and can be synchronized to an external clock. The LT3999 input operating voltage range is set with the precise undervoltage and overvoltage lockouts. The supply current is reduced to less than 1 μA during shutdown. A user-defined RC time constant provides an adjustable soft-start capability by limiting the inrush current at start-up and an onboard cross-conduction prevention circuit increases reliability.
The LT3999 is available in thermally enhanced MSOP-10 and 3 mm × 3 mm DFN-10 packages. The LT3999 E- and I-grade versions operate from a –40°C to 125°C junction temperature. The LT3999 H grade is guaranteed to operate from a –40°C to 150°C operating junction temperature. The LT3999 MP grade is guaranteed to operate from –55°C to 150°C operating junction temperature. Devices are in stock, and the 1,000-piece price starts at $2.75 each for the E-grade.
Summary of Features: LT3999
- Wide VIN Range: 2.7 V to 36 V;
- Dual 1 A Switches;
- Programmable Switching Frequency: 50 kHz to 1 MHz;
- Synchronizable to an External Clock up to 1 MHz;
- Duty Cycle Control for Output Voltage Regulation;
- Low Noise Topology;
- Programmable Input Over & Undervoltage Lockout;
- Cross-Conduction Prevention Circuitry;
- Extended & Industrial Grades: –40°C to 125°C Operating Junction Temp;
- Automotive Temp Grade: –40°C to 150°C Operating Junction Temp;
- Military Temp Grade: –55°C to 150°C Operating Junction Temp.
