Synchronous step-down regulator delivers high efficiency

Linear Technology Corporation has announced the LT8610AX, a 3.5A, 42V input capable synchronous step-down switching regulator, which operates in ambient temperatures up to 175C. Synchronous rectification delivers efficiency as high as 95% while Burst Mode operation keeps quiescent current under 3.5µA in no-load standby conditions. Its 3.7V to 42V input voltage range is ideal for high temperature applications such as down-hole drilling equipment with power sources ranging from 5V to 40V. The device’s electrical parameters are 100% tested at 175C, offering a VREF accuracy of 2% over the entire -40C to 175C temperature range. At ambient temperatures of 175C, the device offers over 90% efficiency (for 12VIN to 3.3VOUT conversions) over a wide load current range of 10mA to 1A, ideal for battery powered applications commonly found in down-hole drilling systems. The device’s Burst Mode operation offers ultralow quiescent current, well suited for applications requiring extended operating battery life. It’s 16-lead thermally enhanced MSOP package provides a compact, thermally efficient footprint. The device utilises internal top and bottom high efficiency power switches with the necessary boost diode, oscillator, control and logic circuitry integrated into a single die. This eliminates the need for any external Schottky diodes, which can be problematic at high temperatures. It’s lack of thermal shutdown is ideal for high temperature environments. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 10mVP-P. The current mode topology enables fast transient response and excellent loop stability. Specialised Cu/Ni/Au bond pad plating ensures long life in high temperature environments. Other features include internal compensation, a power good flag and output soft-start/tracking.