36-VIN, 4-A (IOUT), 1.5-MHz synchronous step-down DC/DC converter offers quiescent current of 70-uA

36-VIN, 4-A (IOUT), 1.5-MHz synchronous step-down DC/DC converter offers quiescent current of 70-uA

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By eeNews Europe

The LT3690 operates within a VIN range of 3.9 V to 36 V, and offers transient protection to 60 V, making it well suited for load dump and cold-crank conditions found in automotive applications. The LT3690’s Burst Mode operation requires only 70 uA 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 170 kHz to 1.5 MHz, enabling the designer to optimize efficiency while avoiding critical noise-sensitive frequency bands. The combination of its 4 mm x 6 mm QFN-26 package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint.     

The LT3690 utilizes a high efficiency 5.5 A, 90 mOhm high-side switch with the necessary boost diode, oscillator, control and logic circuitry integrated into a single chip. The 30 mOhm 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 170 kHz to 1.5 MHz), a power good flag and robust short-circuit protection.     

Availability and Pricing     

The LT3690EUFE is priced at $4.95 each for 1,000-piece quantities. The LT3690IUFE is tested and guaranteed to operate from a -40 to 125°C operating junction temperature and is priced at $5.45 each in 1,000-piece quantities. All versions are available from stock.      

More information about the LT3690 step-down switching regulator at


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