Electronic Design

DC-DC Converter IC Packs Two 12-A MOSFETs

Combing 0.7-µm linear biCMOS with compressed drain lateral DMOS technology, Texas Instruments has released a highly integrated family of synchronous-buck dc-dc converter ICs for powering point-of-load DSPs, FPGAs, and microcontrollers in low-voltage distributed power systems. Labeled SWIFT, for Switcher With Integrated FET Technology, the TPS5461x in-tegrates on-chip a controller, two 12-A power MOSFETs, and other requisite circuitry to simplify power-supply design and slash external component count to a mere six.

The converter can supply up to 6 A of continuous output current at an 85ºC ambient temperature with no air flow. Also, it features more than 90% efficiency. It operates over a 3.0- to 6.0-V input and provides a 0.9- to 3.3-V adjustable output-voltage range with initial accuracy within 1%. Fixed output-voltage versions down to 0.9 V are available with output-voltage accuracy within 2%.

"The SWIFT converter family makes power-supply design from a 3.3-V or 5.0-V bus easier and faster," notes Rich Nowakowski, marketing manager for TI's power-management products. For optimal switching, the converter's frequency can be ad-justed anywhere be-tween 280 and 700 kHz. Or, it can be preset at 350 or 550 kHz, respectively. The built-in high-bandwidth error amplifier lets the converter provide a transient response of 16 µs for a 3-A change in load current. Typical ripple and noise is 1% of the output voltage. Other features include a power-good signal, peak-current limit, thermal shutdown, and undervoltage lockout.

While six members of the 6-A TPS5461x family are internally compensated, the TPS54610 is externally compensated to provide the flexibility of adjusting the output voltage or customizing the loop response. The devices are packaged in a thermally enhanced 28-pin PowerPAD TSSOP package.

SWIFT devices are supported by a software design tool, which can be downloaded from www.power.ti.com. A CD-ROM that's also available calculates values of external components, displays efficiency and loop-response graphs, and provides thermal analysis. However, it doesn't provide any board layout of the designed components. And, TI offers a 3-A 20-pin TSSOP version as well. In quantities of 1000, the 6-A TPS5461x starts at $4.99.

Texas Instruments, Semiconductor Group, Literature Response Center, P.O. Box 954, Santa Clarita, CA 91380; (800) 477-8924, ext. 4500; www.power.ti.com.

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