15A/20A POL regulators offer fast transient response without compensation components

April 10, 2016 // By Graham Prophet
Exar's XR76116 and XR76120, 15A and 20A point-of-load (POL) step-down buck switching regulators employ the company's emulated current mode constant on-time (COT) control. This control loop provides the fast transient response required in demanding applications such as servers.

Improved gate driver technology has reduced dead times to 10 nsec, resulting in improved efficiency across the entire operating range. The XR76116 and XR76120 extend the output current range of the PowerBloxT line of Exar's high current POL regulators up to 20A. The 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. 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. A second output voltage sense pin ensures any failure of the main feedback does not result in damaging voltages being applied to low voltage digital circuitry. These POLs have full range 0.1% load regulation and 1% output accuracy over the full -40°C to 125°C temperature range. Supervisory and protection for proper sequencing, safe operation under abnormal operating conditions and light load operation is built in.


Specified over the -40°C to 125°C temperature range, the XR76116 and XR76120 come in a 5 x 6 mm TQFN package. Pricing starts at $2.70 and $3.20 each, respectively (1000). Evaluation circuit boards are available.


Exar; www.exar.com