Synchronous Buck Controller Converts Directly from 48 to 1 V

Intersil today announced its first 60V synchronous buck controller able to bypass the intermediate step-down conversion stage traditionally employed in industrial applications.

The ISL8117 synchronous step-down PWM controller’s low duty cycle (40 ns minimum on time) and adjustable frequency up to 2 MHz enables the direct step-down conversion from 48 V to a 1V point-of-load. In such applications where a lower output voltage is required, designers have traditionally relied on modules that increase system cost, or two stage DC/DC solutions that decrease efficiency. The device uses valley current mode modulation with adaptive slope compensation to enable stable operation for a wide range of input and output combinations, with no external compensation required. With the ISL8117, engineers can design a complete DC/DC buck converter with 10 components, including external power MOSFETs and passives, and achieve up to 98% conversion efficiency with 1.5 % output voltage accuracy.

The ISL8117 offers programmable soft-start and enable functions along with a power-good indicator for ease of supply rail sequencing and other housekeeping requirements. The ISL8117 utilizes internal loop compensation and single resistor settings for other functions such as operating frequency and over-current protection. Its current mode control enables various applications even with fixed internal compensations. The unique DEM/Skipping Mode at light load lowers standby power consumption with consistent output ripple over different load levels.

The ISL8117 high voltage controller can be combined with Intersil low dropout linear regulators such as the ISL80136, ISL80138, ISL80101A, and integrated FET switching regulators (ISL8023/24 or ISL8016) to support the bulk power rails in a typical process control industrial application.

The ISL8117 is available in 4mm x 4mm QFN and 6.4mm x 5mm HTSSOP packages. Both packages use an EPAD to improve thermal dissipation and noise immunity. Pricing for the QFN package is $1.80 and the HTSSOP is $1.95 in 1k quantities. Two evaluation boards are priced at $80 – the ISL8117EVAL1Z low power (V_in 4.5V-60V and 3.3V_out/6A), and the ISL8117EVAL2Z high power (V_in 18V-60V and 12V_out/20A). Two demonstration reference design boards priced at $60 allow designers to produce low power (factory automation or robotic) and high power (telecom) applications.