Two-phase synchronous dc/dc controller
LINEAR Technology, represented in Australia by Soanar , has released the LTC3802, a dual, two-phase, dc/dc synchronous controller for converting a high input voltage to low output voltages at a high switching frequency.
The modulation architecture allows low duty cycles without compromising the operating switching frequency. The IC has a nominal 550kHz switching frequency that is phase-lockable from 300kHz to 750kHz. It uses small inductors and capacitors for regulating output voltages as low as 0.6V.
The two-phase operation reduces the peak input current ripple, which in turn minimises the number of input capacitors. It has programmable up/down tracking with ratiometric and coincident options. Applications include point-of-load power supplies for sub-1V, 1.xV, 2.xV, and 3.xV in embedded systems, access switch routers, compact PCI, and servers.
The IC operates without requiring any sense resistors. Current limit is adjustable, and overcurrent is detected by sensing the voltage drop across an external MOSFET. The minimum on-time is as low as 50ns (typical). It has a trimmed ±1% 0.6V reference. An output sense function provides real time overvoltage protection.
The LTC3802 is offered in 28-lead SSOP and a 5mm x 5mm QFN package. It is rated for operation from -40°C to 85°C.
18-Jun-2004