High Voltage ICs Can Replace Automotive Surge Suppression Devices

Its 4V to 140V (absolute maximum of 150V) input voltage range allows operation with high-voltage input power supplies or input power with high-voltage surges, eliminating the need for external surge suppression devices. The LTC3895 continuously operates with up to 100% duty cycle when the input voltage drops to 4V, making it ideal for automotive and heavy equipment applications.

The device's output voltage can be set from 0.8V to 60V, output current up to 20A, and efficiency up to 96%. The LTC3895 draws only 40μA in sleep mode with a stable output voltage, making it ideal for always switching on the system. The internal charge pump allows operation at 100% duty cycle with a dropout voltage. This is a useful feature for surge suppression applications as well as battery-powered discharges. The EXTVCC pin allows the LTC3895 to be powered from the output of a switching regulator or other available power source, reducing power consumption and increasing efficiency.

At light loads, the user can select forced continuous mode, pulse skip mode, or low Burst Mode® operation. Its current mode architecture provides very easy loop compensation, fast transient response, and excellent voltage stability. Current sensing is accomplished by measuring the voltage drop across the output inductor (DCR) for maximum efficiency, or by using an optional sense resistor. The short 80ns minimum on time allows high step-down ratios at high switching frequencies. In an overload condition, the current foldback limits the amount of heat generated by the MOSFET. The LTC3895 is packaged in a TSSOP-38 thermally enhanced package, eliminating several pins to achieve high voltage spacing. The device is available in two operating junction temperature versions. The extended and industrial temperature versions operate in the –40°C to 125°C range. High-temperature automotive grades operate in the –40°C to 150°C range.

Relevant LTC38 series products

Author：Brittany Antonia （The author of article owns the copyright.）