Linear Technology Corporation has announced the LT8610AX, a synchronous step-down switching regulator with 3.5A, 42V input capability. The device can operate at ambient temperatures up to 175C. Synchronous rectification provides up to 95% efficiency, while burst mode operation keeps quiescent current below 3.5µA under no-load standby conditions. Its 3.7V to 42V input voltage range is ideal for high temperature applications, such as downhole drilling equipment with a power supply range of 5V to 40V. The electrical parameters of the device are 100% tested at 175C and provide 2% VREF accuracy over the entire -40C to 175C temperature range. At an ambient temperature of 175C, the device can provide more than 90% efficiency (for conversion from 12VIN to 3.3VOUT) over a wide load current range of 10mA to 1A, making it ideal for battery-powered applications commonly found in downhole drilling systems . The device's burst mode operation provides ultra-low quiescent current, making it ideal for applications requiring extended battery life. Its 16-lead thermally enhanced MSOP package provides a compact, thermally efficient package.
The device utilizes internal top and bottom efficient power switches and integrates the necessary boost diodes, oscillators, control and logic circuits into a single chip. This eliminates the need for any external Schottky diodes, which can be problematic at high temperatures. The lack of thermal shutdown is ideal for high temperature environments. Low-ripple burst mode operation maintains high efficiency at low output currents while maintaining output ripple below 10mVP-P. The current-mode topology enables fast transient response and excellent loop stability. Special Cu / Ni / Au pad plating ensures long life in high temperature environments. Other features include internal compensation, power-good flags, and output soft-start / tracking.
