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MONOLITHIC 6A DC/DC STEP-DOWN CONTROLLER

Texas Instruments’ latest additions to its Swift series has further developed the trend for power-supply-IC vendors to supply functions such as point-ofload dc/dc converters in highly integrated packages. The TPS546206-A is a 17V step-down synchronous switcher with integrated FETs. The package itself measures 3.5x3.5 mm and contains the control IC and poweroutput FETs. By the time you have added the required handful of passive components, you can pack a complete 6A power solution into less than 195 mm², TI says. Unlike some vendors’ approach to the problem, TI’s package hosts a monolithic device with integrated high- (26 mΩ) and low-side (19mΩ) FETs. It will down-convert supplies ranging from 1.6 to 17V, although you do need to provide a separate supply for control and gate-drive purposes that is not below 4.5V. The inductor will set the height—or profile—of your converter design; TI has a suggestedparts list, in which the smallest suitable inductor has a 3-mm profile. The device will run from 200 kHz to 1.6 MHz, and you can lock its switching frequency to an external clock. You need to provide an external compensation network of around five passive components, and TI’s online—or downloadable—software package SwitcherPro will assist with calculating those component values. Not integrating these compensating components, TI says, costs very little in board area and enhances design freedom. The chip has a 0.8V reference—0.8V also being the lower limit of the output voltage—and yields a 1%-accurate output across its range. Peak efficiency is 95%, and the chip will maintain better than 90% over an output range of 1 to 6A, when deriving 3.3V from a 12V input. The TPS54620 costs $1.95 (1000).

Texas Instruments, www.ti.com.