150 Degrees C Triple-Output Synchronous Step-Down Controllers
Linear Technology Corporation announces the H- and MP-grade versions of the LTC3853, a triple-output synchronous step-down switching regulator controller. This device operates over a 4.5V to 24V input voltage range, can produce output currents up to 20A per phase with output voltages ranging from 0.8V to 13.5V at up to 95% efficiency. These H- and MP-grade versions are guaranteed over operating junction temperatures from -40 to 150 degrees C and -55 to 150 degrees C, respectively.
The LTC3853 has 1.1-Ohm on-chip MOSFET gate drivers. The constant-frequency current mode architecture allows a selectable fixed or synchronized frequency from 250kHz to 750kHz. Power loss and supply noise are minimized by operating the three stages 120 degrees out-of-phase. Output current sensing is accomplished by measuring the voltage drop across the output inductor (DCR) or by using an optional sense resistor. Current foldback limits MOSFET heat dissipation during short-circuit and overload conditions. In addition, the LTC3853 has adjustable soft-start or tracking. Selectable Burst Mode® operation, pulse skipping or continuous inductor current modes are user controlled to optimize light load efficiency.
The LTC3853 features a precision 0.8V reference with an accuracy of ±1.25% over a -55 to 150 degrees C operating temperature range. With up to 98% duty cycle, the LTC3853 has a very-low dropout voltage, a useful feature for extending run times in battery-powered applications. The LTC3853 is available in a thermally-enhanced 6mm x 6mm QFN-40 package. Pricing for 1,000-piece quantities begins at $4.24 each.