1997-10-13 , E/IC-842/540

Highly efficient switchmode DC/DC converters are an essential part of battery powered equipment such as mobile phones, personal digital assistants (PDAs) and palmtop computers. However, because of their switchmode operation, these converters are also a potential source of electromagnetic interference (EMI). This is particularly significant in mobile phones where EMI generated by the converter can cause spurious signals to appear on the phone's RF input and output, significantly affecting the quality of speech transmission.

With the launch of its new TEA1206 single-chip DC/DC converter at Power '97, Philips Semiconductors solves the EMI problem by allowing designers to synchronize the converter's switching frequency to the mobile phone's reference frequency, anywhere in the range 9 MHz to 20 MHz. Compared to other converters in Philips Semiconductors' TEA120x family, the TEA1206 up/down converter also has a higher maximum switching frequency (585 kHz) and a continuously variable 3 V to 5 V output voltage range - giving designers greater design FLEXibility and allowing them to use smaller filter/flyback inductors and capacitors. Enhanced efficiency under low and high load current conditions, plus a quiescent current consumption of only 50 µA, makes the TEA1206 the most energy efficient low-voltage single-chip DC/DC converter on the market.

"The TEA1206 is the first in a new generation of DC/DC converters from Philips Semiconductors that will offer greater conversion efficiency, better output voltage accuracy and a smaller overall pc board footprint," said Product Marketing Manager Leo Warmerdam.

Using a unique combination of pulse width and pulse frequency modulation, the TEA1206 maintains typical conversion efficiencies in excess of 96% and an output accuracy better than 5% under all load conditions. It also features a precisely defined current limit that suits it for use with LiIon batteries, and an under-voltage lock-out circuit that prevents lock-up situations occurring at low supply voltages.

Philips Semiconductors, the largest European semiconductor company, is also introducing the TEA1205A DC/DC converter at Power '97. This new converter, which synchronizes to a single master clock frequency of 13 MHz (± 1 MHz) and is restricted to up-conversion, has fixed output voltage settings. In applications where these settings are adequate, it saves the cost and complexity of an external resistor network.

Both devices are fabricated in Philips Semiconductors' advanced 0.8 µm CMOS process and are packaged in a space saving 8-pin small-outline surface-mount package.

Philips Semiconductors, a division of Philips Electronics NV, headquartered in Eindhoven, The Netherlands, is the ninth largest semiconductor supplier in the world and the third largest supplier of discretes in the world. Philips Semiconductors' innovations in digital audio, video, and mobile technology position the company as a leader in the consumer, multimedia and wireless communications markets. Sales offices are located in all major markets around the world and are supported by systems labs.

Power '97, The Fifth International Conference on Power Requirements for Mobile Computing and Wireless Communication (October 12 -15, Santa Clara, California, USA) is a highly specialist exhibition that provides manufacturers of portable computing and cellular communication devices with the opportunity to keep pace with the latest hardware and software developments in power supplies and power management for mobile products and services. The conference, for which Philips Semiconductors is one of nine sponsors, has attracted some 700 delegates from around the world. Its extensive program of technical papers is accompanied by an exhibition of products and services.