Transformer driver consumes less than 1µA during shutdown
The LT3999, a monolithic push-pull isolated DC/DC transformer driver, has been released by Linear Technology. Operating over an input voltage range of 2.7-36V, the driver is designed for power levels up to 15W. The driver, which features two 1A current limited power switches is, therefore, suitable for automotive, industrial, medical and military applications.
Undervoltage and overvoltage lockouts set the driver's input operating voltage range, while the programmable duty cycle sets the output voltage which turns ratio of the driver. The switching frequency is adjustable from 50kHz to 1MHz and can be synchronised to an external clock. During shutdown, supply current is reduced to less than 1µA. To provide an adjustable soft-start capability, a user-defined RC time constant limits the inrush current at start-up. The driver also features an onboard cross-conduction prevention circuit which increases reliability.
Available in MSOP-10 and 3x3mm DFN-10 packages, the LT3999 E- and I-grade versions operate from a -40 to +125°C junction temperature. The H grade operates from a -40 to +150°C junction temperature, while the MP grade operates from a -55 to +150°C junction temperature. For the E-grade, which is sold in 1,000-piece quantities, prices start at $2.75 each.