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highpowerZONE Products for the week of June 15, 2009
Texas Instruments Says…
TPS54620: Smallest 6-A, 17-V Step-Down Dc-Dc Converter
Single-chip SWIFT point-of-load device for telecom and computing systems supports up to 17 V; 60% smaller package than multi-chip converters
Extending its family of easy-to-use SWIFT power management integrated circuits (ICs), Texas Instruments (TI) introduced the industry’s smallest single-chip, 6-A, 17-V step-down synchronous switcher with integrated FETs. The high-performance TPS54620 is 60 percent smaller than today’s multi-chip converters, resulting in a complete 6-A power solution less than 195 mm2 -- one-fourth the size of a postage stamp. The 1.6-MHz monolithic DC/DC converter supports input voltages from 4.5 to 17 V, allowing it to manage space-constrained 5-V and 12-V point-of-load designs, such as a wireless base station or high-density server.
“As telecommunications designs become more dense and complex, there is a need for more integrated, highly efficient power management devices that support a 12-V power rail,” said Steve Anderson, senior vice president of TI’s Power Management business unit. “We continue to develop smaller, more robust SWIFT converters, so designers can more quickly develop differentiated products unique to the market.”
In addition to size improvements, the TPS54620 offers a high degree of performance and reliability, such as a highly accurate voltage reference with +/- one percent accuracy over temperature. Achieving a 95-percent power conversion efficiency and a 25 percent lower Rds(on) than previous 6-A SWIFT devices, the converter easily powers deep sub-micron TI digital signal processors (DSPs) and other embedded processors, such as FPGAs and ASICs.
EN-Genius Says…
We reviewed the first SWIFT (Switcher With Integrated FET Technology) parts in August 2001, and since then many millions have been shipped. The original parts TPS54610 – TPS54616 (variable output + five fixed voltage versions) were 6 A continuous, 12 A peak parts in thermally-enhanced TSSOP-28 with a catalog price of $4.99 in 1000-piece lots. The ICs allowed for a reduction from 20 components down to 7 components for a design solution. A later version was offered as the TPS54617 in QFN-34 with an input voltage range of 3.5 V to 6.0 V and outputs from 0.9 V to 4.5 V.
The big jump with the TPS54620 is that the input rail can now be up to 17 V allowing for the part to be used with the ubiquitous 12 V rails that are still popular in many industrial applications. The size too has been reduced down to a QFN-14, dramatically reducing the real estate needs on a PCB.
The TPS54620 is, again, a 6 A continuous synchronous (8 A peak) buck switcher with integrated FETs. Efficiencies can be above 90% with a load of more than 1 A, even with the input at 17 V. The supply current in shutdown is a typical 2 µA, while the operating, non-switching, supply current is a typical 600 µA. The high-side switch resistance is about 30 mΩ and the low-side is about 20 mΩ. Both MOSFETs are n-channel. The output voltage is adjustable using the normal potential divider on the output to feed a Sense pin.
The switching frequency range is about 200 kHz to 1.6 MHz, set by a single resistor, or it can be locked to an external source. The internal reference at 0.8 V has a ±1% tolerance over temperature. There is a slow-start and sequencing arrangement, a poor-good monitor for overvoltage and undervoltage, and an adjustable input undervoltage lock-out. The device works in continuous-conduction mode at all loads.
Separate VIN and PVIN pins are provided on the device. The VIN is for the internal circuit operations and must be at least 4.5 V. The PVIN is the input pin for the power conversion and may be powered separately from VIN, down to 1.6 V.
TI’s SwitcherPro tools (on line or downloadable) can be used to design the TPS54620 circuit for your application.
TI has the measure of this market and although there is a lot more competition than there was when we reviewed the first SWIFT products in 2001, getting the size down has become of significant importance in designs. Broadening the available market to 12 V inputs will also do nothing but good for TI’s sale volumes. Overall, the pricing is 60% less than in 2001 – which speaks loudly about how markets have changed. Applications are wherever packing density and performance coincide and 6 A is a sweet spot in load requirements. The part will do exceptionally well.
The TPS54620 is in production in thermally-enhanced QFN-14 priced at $1.95 in 1000-piece lots.
Data Sheet
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