The XR761xx family is designed to achieve excellent transient response and output accuracy, of 0.25% load and 0.1% line regulation, using Exar's proprietary emulated current mode Constant On-Time (COT) control loop. These devices deliver core voltage rails for ASICs, FPGAs, DSPs and Network Processors in communications, networking and industrial markets.
Input voltage range is 4.5V to 22V for an adjustable output voltage from 0.6V to 18V. With its 0.1% line regulation across the entire input voltage range and 1% output accuracy over full temperature range, XRP761xx provides increased headroom. The emulated current mode COT control scheme has the fast transient response of conventional COT control loops without any of the compromises. Exar's COT control loop enables operation with ceramic output capacitors, eliminating loop compensation, which simplifies system design and reduces overall component count. The XR761xx offers a suite of supervisory and protection features for proper sequencing, safe operation under abnormal operating conditions and light load operation.
The control loop also maintains constant operating frequency. A selectable power saving mode allows the user to operate in discontinuous mode (DCM) at light current loads, significantly increasing the converter efficiency. The XR76108 and XR76112 come in 30-pin 5 x 5 [mm] QFN packages priced from $2.50 and $2.70 respectively (1000). XR76115 is in a 30-pin 6 x 6 QFN for $3.50 (1000).