Making power supply design easier and faster, Texas Instruments (TI) announced a series of high-performance synchronous-buck DC/DC converters that enable designers to quickly develop a power supply with as few as six external components. The new synchronous DC/DC converters with internal 12A MOSFET switches are capable of supplying greater than 6-A of continuous output current over the entire operating temperature range and operate over a 3.0 to 6.0V input voltage range. By integrating power MOSFETs in a synchronous-buck configuration, the devices are capable of up to 95 percent efficiency and are well suited for powering point-of-load DSP, FPGA and microcontroller applications, notebook PCs, networking and optical communications systems, and low voltage, high density distributed power systems. (See power.ti.com/swift).

The TPS5461x SWIFT^™ (Switcher With Integrated FET Technology) DC/DC converters save development effort not only with the integration of power FETs and compensation circuitry, but also with an interactive software development tool that speeds novice and veteran power supply designers through the entire external component selection process. The development tool provides a bill of materials, reference schematic, loop response graphs and an efficiency curve based on the designer’s inputs. External inductors and capacitors are chosen from the tool’s database of components (users can also add their favorite components to the database).

"Strong time-to-market pressures make power supply development a critical path for manufacturers of a variety of advanced end equipment," said Rich Nowakowski, product marketing manager, TI Power Management Products. "When a complex DC/DC controller design using external MOSFETs is too time-consuming or risky, and a DC/DC module is too expensive, TI’s high-performance TPS5461x SWIFT DC/DC converter will make designing power supplies from a 3.3/5 V bus easier and faster."

The TPS5461x devices offer a high output current in a small space while providing integrated protection features, such as power good, over-current protection, thermal shutdown and under voltage lockout. An integrated synchronous rectifier and a low 30 mW r_ds(on) of the power MOSFETs enable the device to achieve efficiencies greater than 95 percent. To address an application’s switching noise sensitivity, the switching frequency can be one of two preset values or adjusted anywhere between the range of 280 to 700 kilohertz (kHz). Additionally, excellent heat transfer resulting from TI's PowerPAD^™ package enables up to three times the thermal performance of other packaging without the need for bulky heat sinks. An externally compensated option is also available, which adds flexibility for adjusting the output voltages or customizing loop response characteristics to the specific needs of the application.

Available Options

Fixed or adjustable output voltage versions are available down to 0.9 V with 2.0 percent total accuracy.

Part Number	Output Voltage	Feedback
TPS54611	0.9 V	Internally Compensated
TPS54612	1.2 V	"
TPS54613	1.5 V	"
TPS54614	1.8 V	"
TPS54615	2.5 V	"
TPS54616	3.3 V	"
TPS54610	Adjustable down to 0.9 V	Externally Compensated

Texas Instruments Incorporated, Semiconductor Group, SC-01130, Literature Response Center, P.O. Box 954, Santa Clarita, CA 91380. Phone: 800-477-8924, ext. 4500

The TPS5461x is DC/DC converter with integrated FET technology can handle up to 6A continuously. The product is targeted at the unsophisticated power supply designer. It uses the companies sophisticated packaging technology called PowerPad to help deal with the package and thermal issues.

TI really zeroed-in with laser-guided precision with this product and made it for engineers in mostly small companies. It was designed for users who may perform a whole range of circuit board design tasks and are not analog savvy. These are the engineers that wear many hats and they need something that is easy to use. TI created a software tool that allows them to step through the entire component selection. This software helps the development of several products on the market such as DC-DC controllers, external FETs that are too complicated, and low drop-out regulators that are too inefficient and require large heat sinks. Most multitasking designers don't have enough time to design these and make their deadlines.

Internally or externally compensated versions of the converter are offered. For internal compensation the feedback response loop in the power supply is integrated and is inherently very stabile. The stability is determined by the output filter (inductor and capacitor). However, there is a tradeoff because you have a limited number of combinations. The engineers can, with the proper experience, do the compensation himself and therefore be able to choose for themselves the output inductor and capacitor. The TI SWIFT^™ (Switcher With Integrated FET Technology) software tool will help you determine the best combination. There are combinations of components in the SWIFT database from a variety of companies and you can add more if you need it. TI used the extensive experience of their own design experts to seed the database.

TI will roll out separate converters, over the space of a year, that accommodate different needs. For example, the converters can be used for optical networking cards that have 48 V and must be stepped down to 3.3 V, or for designs that have four DSPs that might need 4 A or for designs that have 2 FPGAs that need from 2 - 2.5 A. There probably isn't any need to go lower than 250 mA because LDOs can take care of those design needs. It's usually the higher currents that you need switching DC/DC regulation so you maintain efficiency and control heat.

The SWIFT^™ software tool is pretty slick and what's better - TI is offering it for free. It has the required inputs including input/output voltage, output current, and optional inputs that the you can specify in more such as what the power supply will be. When you finish with your inputs you click the GO icon and bada-bing-bada-boom, the software gives you the schematic. You can look closer and change values of individual components and then run the program again until you are satisfied with the result. It also offers a bill of material (BOM), a thermal analysis to see how many watts are being dissipated, it will display the efficiency calculation so you can see what the efficiency graph will look like from 0 to full load current (up to 6 A), and most importantly it will do a loop response graph so you can check the stability of your power supply. The tool can optimize for gain or phase margin, which you can enter in the optional input section and it will redesign your circuit according to your inputs. Like I said, it's pretty slick.

The TPS5461x DC/DC converters will be available in September from TI and its authorized distributors. The devices are packaged in 28-pin PowerPAD^™ thin-shrink small-outline packages (6.4 mm x 9.7 mm) for thermal enhancement and space savings. Suggested resale pricing is $4.99 each in quantities of 1,000.

Adding to the SWIFT^™ family of DC/DC converters, a 3-A 20-pin TSSOP version is planned for volume production in 4Q 2001 with samples available now. The device incorporates the same features and voltage options as the TPS5461x 6-A version and is supported by the software tool.

The SWIFT^™ software development tool is available for free and can be downloaded from Ti's power management web site (power.ti.com). A CD-ROM version is also available. To further help system developers with designing power supply solutions, TI is offering evaluation modules, reference designs and other support collateral to reduce the power management design burden.

Data sheets:
www-s.ti.com/sc/psheets/slvs398a/slvs398a.pdf
www-s.ti.com/SC/psheets/slvs400/slvs400.pdf