Exar Corporation, a supplier of analog mixed-signal products serving the industrial, high-end consumer and infrastructure markets, introduced the XR76116 and XR76120, 15A and 20A point-of-load (POL) step-down buck switching regulators using the latest generation of Exar’s patented emulated current mode constant on-time (COT) control. This control loop provides the fast transient response required in demanding server applications while making implementation simple and easy. Improved gate driver technology has reduced dead times to 10ns, resulting in improved efficiency across the entire operating range.
The XR76116 and XR76120 extend the output current range of the PowerBloxTM line of Exar’s high current POL regulators up to 20A. The patented COT control loop enables operation with ceramic output capacitors without degradation in transient performance and eliminates loop compensation components, making a simpler and more reliable design. Additional features targeted at server applications include a power good pin which maintains a low impedance when the chip is unpowered thereby avoiding false power good signals. Also, there is a second output voltage sense pin, ensuring any failure of the main feedback does not result on damaging voltages being applied to expensive low voltage digital circuitry. These POLs have exceptional full range 0.1% load regulation and 1% output accuracy over the full -40°C to 125°C temperature range. A host of supervisory and protection features for proper sequencing, safe operation under abnormal operating conditions and light load operation is built in.