Milpitas, Calif.—Intersil Corporation's two-phase ISL6310 and three-phase ISL6308 pulse width modulation (PWM) controllers with high-current, integrated MOSFET drivers for server and embedded system peripherals tout high-accuracy voltage regulation of the kind typically reserved for processor core applications.
"By integrating the MOSFET driver with the PWM controller, Intersil reduces the number of external parts, providing the customer with cost and space savings in their power management designs," said George Lakkas, senior product marketing manager of the company's Power Management group. "These devices also feature differential remote voltage sensing for high system accuracy, and a 2-bit DAC (digital-to-analog converter) that allows the designer to program the output voltage without the use of external resistors."
The devices, with ±0.8 percent system acccuracy over temperature (for the 0.6- and 0.9-volt versions; ±0.5 percent for the 1.2- and 1.5-volt versions) and a programmable frequency of up to 1.5 MHz per phase, also feature pre-biased load start-up and current sink/source capability. They allow users to program for voltage droop for such applications as double data rate (DDR) memory. Other applications include high-current, low-voltage point-of-load converters.
Uses set the output voltage using an on-chip DAC or an external precision reference, such as the ISL60002 series. A two-bit code programs the DAC reference to one of four possible values (0.6, 0.9, 1.2 or 1.5 volts). A unity-gain, differential amplifier facilitates remote voltage sensing to compensate for any potential difference between remote and local grounds. The output voltage can also be offset using a single external resistor.
The operating voltage of the chips' MOSFET gate drivers is programmable from 5 to 12 volts, and thus the designer can secure the optimum trade-off between switching and conduction losses associated with the upper and lower MOSFETs. The droop function can be disabled for applications that have less stringent output voltage variation requirements or experience less severe step loads. These devices use both DC resistance (DCR) and on-resistance (rDS(on)) current sensing in combination, a unique feature, to secure the advantages of both methods.
The ISL6310 and ISL6308 include comprehensive over-voltage and over-current protection. Both parts have a pre-POR (power-on reset) over-voltage protection feature. The chips' OVP output is also provided to drive an optional crowbar device. The over-current protection level is set through a single external resistor. Other protection features include protection against an open circuit on the remote sensing inputs.
Additional information on the ISL6310 is available by clicking here and on the ISL6308 by clicking here. The ISL6310, in a 32-lead QFN standard or lead-free package, is priced at $1.80 each. The ISL6308 is available in a 40-lead QFN standard or lead-free package and is priced at $2.25, both in 1k quantities.
Intersil Corp., 1-888-468-3774, www.intersil.com