DC-DC switching controller features current-mode and voltage-mode options for high-current applications

June 12, 2012 // By Paul Buckley
Analog Devices, Inc. (ADI), has introduced a wide-input-range, synchronous, step-down DC-to-DC controller with voltage tracking and advanced clock synchronisation capability.

The versatile ADP1853 can be configured as a voltage-mode controller with input feed-forward or as a current-mode controller, depending on the application and customer preference.

The ADP1853 has clock-out and synchronisation input to ensure 180-degree phase-shifted synchronisation, eliminating troublesome ‘beat’ frequencies and reducing system input capacitance when multiple devices are used.  The new controller’s tracking capability enables controlled start-up. Simple, robust sequencing can be implemented using the precision enable and power-good functions. The ADP1853 can be connected in parallel to achieve higher current delivery—up to 50 A depending on the external FETs. The ADP1853 is designed for high-efficiency, high-current, fast-transient, point-of-load applications in a broad range of communications networking, industrial, medical, and consumer applications.

In current-mode control, the ADP1853 architecture detects the current during the off period to improve noise immunity using the on-resistance of the low-side FET—or a series sense resistor for higher accuracy. Externally adjustable slope compensation is added to optimise performance in current mode. With minor adjustments to external resistor settings, the ADP1853 can be configured for voltage-mode control, using input-line feed-forward for excellent line rejection. The ADP1853 has a selectable pulse-skip mode to increase efficiency during light load operation. The device also has an accurate current limit, which allows optimal sizing selection of external components to optimise valuable PCB space. The ADP1853 is accompanied by ADI’s online ADIsimPower tools for ease of use and reduced design time.

Availability and Pricing

The ADP1853ACPZ-R7 packaged in a 20-lead LFCSP is in full production and is priced at $1.20 each per 1k units.

The ADP1853-EVALZ is in full production in June 2012 and is priced at $60.00 each per 1k units.

More information about the ADP1853 step-down DC-to-DC controller at