Integrated MOSFETs and Driver Boosts Converter Efficiency

Nov 16, 2005 11:03 AM

Vishay Intertechnology has released two high-speed dc-dc converter solutions that integrate the control MOSFET, the synchronous MOSFET and driver circuit in a PowerPAK MLF package. The products simplify the single and multiphase dc-dc converter design process. Intended for applications such as point-of-load (POL) power converters, and 3.3 V, 5 V and 12-V intermediate bus architecture environments, the devices conserve board space and power. The integration of the MOSFETs and driver minimizes the parasitic leakage inductance that can cause ringing and spikes at the switching node. Break-before-make operation provides “shoot-thru” immunity and minimizes dead time. These devices also feature undervoltage lockout and a turn-on/turn-off capability. An internal bootstrap diode further reduces the number of external components required.

The SiC714CD10 and SiC711CD10 can be used along with any PWM IC or ASIC to produce a highly efficient buck converter. A low-side MOSFET control pin enables pre-biased start-up, which prevents an undesirable sinking current from a pre-charged output capacitor from causing problems, particularly in POL and server applications. The new SiC714CD10, rated for input voltages from 3.3 V to 16 V, delivers up to 27 A of continuous output current in still air and is optimized for a 10% duty cycle ratio. Typical on-resistance values are 3 mΩ for the low-side and 10.2 mΩ for the high-side MOSFET. Vishay’s SiC711CD10 is rated for input voltages from 3.3 V to 16 V and a 40% duty cycle, and it provides continuous output current up to 25 A. Typical on-resistance values are 4 mΩ for both the high- and low-side MOSFETs.

Both devices are optimized for 12-V to logic level conversion and are rated for a switching frequency range of 100 kHz to greater than 1 MHz. The PowerPAK MLF 10-mm × 10-mm package provides a low thermal resistance, and its simple pad geometries enable straightforward board layout and assembly. Pricing in 100,000-piece quantities is $2.

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