LT8614 Synchronous Step-Down Silent Switcher™

Analog Devices' unique Silent Switcher architecture reduces EMI / EMC emissions by more than 20 dB, well below the CISPR 25 Class 5 limit. Even with switching frequencies in excess of 2 MHz, synchronous rectification delivers efficiency as high as 96% while Burst Mode^® operation keeps quiescent current under 2.5 μA in no-load standby conditions. Its 3.4 V to 42 V input voltage range makes it ideal for automotive and industrial applications.

The LT8614’s internal high-efficiency switches can deliver up to 4 A of continuous output current to voltages as low as 0.97 V. Its Burst Mode operation provides ultra-low quiescent current, making it well-suited for applications such as automotive "always-on" systems, which need to extend operating battery life. The LT8614’s unique design maintains a minimum dropout voltage of only 200 mV at 1 A under all conditions, enabling it to excel in scenarios such as automotive cold-crank. Furthermore, a fast minimum on-time of only 30 ns enables 2 MHz constant frequency switching from a 16 V input to a 1 V output, enabling designers to optimize efficiency while avoiding critical noise-sensitive frequency bands. The LT8614’s 20-lead 3 mm x 4 mm QFN package and high-switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint.

The LT8614 utilizes internal top and bottom high efficiency power switches with the necessary boost diode, oscillator, control, and logic circuitry integrated into a single die. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 10 mV_PK-PK. Special design techniques and a new high-speed process enable high efficiency over a wide input voltage range, and the LT8614’s current mode topology enables fast transient response and excellent loop stability. Other features include internal compensation, a power good flag, output soft-start/tracking, and thermal protection.

The LT8614EUDC is packaged in a 3 mm x 4 mm QFN package. An industrial temperature version, the LT8614IUDC, is tested and guaranteed to operate from a -40°C to 125°C operating junction temperature. An automotive temperature version, the LT8614HUDC, is tested and guaranteed to operate from a -40°C to 150°C operating junction temperature.

Features
Silent Switcher architecture: Ultra-low EMI / EMC emissions High efficiency at high frequency Up to 96% efficiency at 1 MHz Up to 94% efficiency at 2 MHz Wide input voltage range: 3.4 V to 42 V Ultra-low quiescent current Burst Mode operation: 2.5 μA IQ regulating 12 VIN to 3.3 VOUT Output ripple < 10 mVP-P		Fast minimum switch-on time: 30 ns Low dropout under all conditions: 200 mV at 1 A Safely tolerates inductor saturation in overload Adjustable and synchronizable: 200 kHz to 3 MHz Peak current mode operation Accurate 1 V enable pin threshold Internal compensation Output soft-start and tracking Small 18-lead 3 mm × 4 mm QFN

Applications

• Automotive and industrial supplies
• General purpose step-down
• GSM power supplies