DC-DC Controller Regulates Low Output Voltages

Jun 15, 2004 12:09 PM
Edited by PETech Staff

Linear Technology Corp.'s new LTC3802 is a wide input voltage range dual, 2-phase dc-dc synchronous controller for converting a high-input voltage to low-output voltages at a high switching frequency. This is accomplished with a leading-edge modulation architecture that allows extremely low duty cycles without compromising the operating switching frequency. With a fast nominal 550-kHz switching frequency that is phase-lockable from 300 kHz to 750 kHz, the LTC3802 uses lower value, small size inductors and capacitors for regulating output voltages as low as 0.6 V.

The LTC3802's 2-phase operation reduces the peak input current ripple, which in turn minimizes the number of input capacitors. For precision power up and down sequencing of multiple supply rails, the IC features programmable up/down tracking with ratiometric and coincident options. Applications include point-of-load power supplies for sub-1 V, 1.x V, 2.x V and 3.x V in embedded systems, access switch routers, compact PCI and servers.

The LTC3802 operates without requiring any sense resistors. In addition to reduction in system cost, the No RSENSE ™ operation improves efficiency, especially in low-output voltage, high-current designs. 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 50 ns (typical). The IC features a trimmed ±1% 0.6-V reference. Furthermore, an output sense function provides real time overvoltage protection.

The LTC3802 is offered in 28-lead SSOP and a 5 mm x 5 mm QFN packages. It is rated for operation from –40°C to 85°C. Pricing for 1000-piece quantity starts at $4.80 each.

For more information, visit www.linear.com.

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