Linear Technology announces the LT3690, a 36V input capable, synchronous step-down switching regulator which can deliver up to 4A of continuous output current at efficiencies as high as 93%. The LT3690 operates within a VIN range of 3.9V to 36V, and offers transient protection to 60V, making it well suited for load dump and cold-crank conditions found in automotive applications. The LT3690's Burst Mode® operation requires only 70uA of quiescent current, ideal for applications such as automotive or telecom systems, which demand always-on operation and optimum battery life. Switching frequency is user-programmable from 170kHz to 1.5MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands. The combination of its 4mm x 6mm QFN-26 package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint.
LT3690 utilizes a high efficiency 5.5A, 90mOhm high-side switch with the necessary boost diode, oscillator, control and logic circuitry integrated into a single chip. The 30mOhm internal synchronous power switch increases efficiency and eliminates the need for an external Schottky catch diode. Low ripple Burst Mode operation maintains high efficiency at low output current while keeping output ripple below 15m VPK-PK. Special design techniques enable high efficiency over a wide input voltage range and the device's current mode topology enables fast transient response and excellent loop stability. Other features include external synchronization (from 170kHz to 1.5MHz), a power good flag and robust short-circuit protection.