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4 February 2008


Infineon ships first CMOS RF switch on silicon with GaAs performance

Infineon Technologies AG of Neubiberg, Germany is shipping in volume what it claims are the world’s first RF switches manufactured in a CMOS-based process on silicon wafers offering equivalent performance to RF switches manufactured using gallium arsenide process technology. Previously, CMOS-based RF switches had to be manufactured on dedicated, much more expensive sapphire wafers to reach the performance of GaAs switches.

Picture: Infineon's 0.79mm x 0.54mm CMOS RF switch BGS12A, which occupies about 60%
less board space in a mobile device than the smallest GaAs RF switch package on the market while offering equivalent performance, it is claimed.

The first product in a whole new family of CMOS-based RF switches, the BGS12A, is available in a fine-pitch wafer-level package (WLP) with dimensions of just 0.79mm x 0.54mm, which is about 60% less printed circuit board (PCB) space compared to the smallest packaged GaAs RF switch on the market, Infineon claims. In many wireless products (including cell phones, WLAN, WiMAX, GPS navigation systems, Bluetooth accessories or remote-keyless entry), RF switches are typically used to implement switching functions for receiving and transmitting (Rx/Tx) data, band select or antenna diversity applications as well as enabling worldwide roaming. On average, mobile devices typically have one RF switch, but some multi-band multi-mode phones have up to four.

“Infineon’s CMOS-based RF switches come in a tiny chip-scale package and require no further external components, such as level shifters, offering more space savings for various board designs,” says Michael Mauer, senior director of Silicon Discretes at Infineon. “With the increasing complexity of modern mobile devices, RF switches are expected to substitute today’s PIN diodes in the next five years.”

According to market research firm Strategy Analytics, the market for RF switches comprised about 2bn pieces in 2006 and is expected to double to about 4bn by 2011.

Infineon’s new RF switches are manufactured in a unique RF CMOS technology, combining the benefits of CMOS with what is claimed to be outstanding RF performance (low insertion loss, low harmonic distortion, good isolation and high power levels). Inherent CMOS advantages include high integration capabilities, cost effectiveness and electrostatic discharge (ESD) robustness. Compared to existing solutions, the CMOS-based RF switches offer the highest integration capabilities; are less expensive than GaAs devices; and allow higher battery life than PIN diodes, since current consumption is significantly reduced. All Infineon RF switches require no external direct current (DC) blocking capacitors and integrate all control logic. CMOS-compatible logic levels (1.4-2.8V) eliminate the need for external level shifters.

The BGS12A is a general-purpose single-pole double-throw (SPDT) RF switch designed for power levels of up to 20dBm, with a P -1dB above 30dBm. The new RF switch offers RF performance with an insertion loss of only 0.3dB at a frequency of 1.0GHz, low harmonic distortion, isolation of 34dB at 1.0GHz, and a switching time of less than 4µs. The interfaces are protected against 1.5kV HBM (human body model) ESD, which improves production yield for manufacturers of mobile device modules. The BGS12A is suited to use in low-and medium-power applications of up to 3GHz. Pricing starts at $0.70 per piece for quantities of 1000 units.

In second-half 2008, Infineon expects to start volume production of further members of the new RF switch family with additional package options including a thin small leadless package (TSLP) with up to 16 pins, higher power levels of 38dBm, and up to nine Tx/Rx ports for a broad range of wireless applications.

See related item:

Infineon targets radar ICs at mid-range cars

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