Versatile DC-DC Switching Controllers for High-current Applications

The versatile ADP1851/53 can be configured to work as a voltage-mode controller with input feed-forward or as a current-mode controller, depending on the application and customer preference. The ADP1851/53 are designed for high efficiency, high current, fast, transient point-of-load applications in a broad range of communications networking, industrial, medical, and consumer applications.

The ADP1851/53 can be connected in parallel to achieve higher current delivery—up to 50 A depending on the external FETs. The ADP1851 features a synchronisation input eliminating troublesome “beat” frequencies and reducing system input capacitance when multiple devices with phase-shifted synchronisation are used. The ADP1851 also has a tracking capability that enables controlled start-up. Simple, robust sequencing can be implemented using the precision enable and power-good functions. The ADP1851 is available in a 16-lead LFCSP (4-mm x 4-mm) package while the ADP1853 with clock out is available in a 24-lead (4-mm x4-mm) LFCSP package.

More About the ADP1851/53 Versatile DC-to-DC Switching Controller Series
In current-mode control, the ADP1851/53 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 ADP1851/53 can be configured for voltage-mode control for improved noise performance, using input line feed-forward for excellent line rejection. The ADP1851/53 series has a selectable pulse-skip mode to increase efficiency during light load operation. The device also has an accurate current limit, which allows for the sizing selection of external components to optimise valuable PCB space. The ADP1851and ADP1853 are supported by ADI’s online ADIsimPower tools, making the device easy to use and reducing design time.

ADP1851/ADP1853 Key Features and Benefits:
• Configurable as voltage-mode or current-mode controller depending on the application and customer preferences
• Wide range input from 2.75 V to 20 V allows operation from commonly used voltage rails: 3.3 V, 5 V and 12 V
• Power-good and precision enable simple, robust sequencing and health detection
• Programmable, accurate current limit optimises output inductor and solution size
• Synchronisation function eliminates potential “beat” frequencies and can be used to reduce input current ripple using phase-shift synchronisation
o ADP1853 adds clock out master feature
• Reference accuracy: ±1% over the temperature range from –40°C to +125°C and ±0.5% from –40°C to +85°C.
• Selectable pulse-skip mode for energy saving at light load
• Easy to Use ADIsmPower tool reduces design time

The ADP1851 is currently in full production in a 16-lead LFCSP package, with a temperature range of –40°C to +125°C priced at $1.05 (US) each per 1,000