These transistors are mainly designed for sensor deployments which require very low-noise signal amplification to achieve high signal-to-noise ratio (SNR). Among the key target applications are analogue and digital microphone amplifiers, which are widely used in mobile phones and headsets, as well as implantable medical devices, such as pacemakers.
The 1.8V low-noise NMOS transistor introduced by X-FAB delivers an improvement factor of eight times lower flicker noise compared to the standard XH018 device. The 3.3V low-noise NMOS transistor gives up to ten times lower flicker noise, while the flicker noise for the 3.3V low-noise PMOS transistor that complements it is halved for all drain currents.
Flicker noise, also known as 1/f noise, is the dominant noise at low frequencies, between 1 Hz to 1 MHz. For applications working in this spectrum, it is important that the flicker noise is kept to a minimal level.
Using these complementary low-noise 3.3V transistors makes it easier for designers to realize noise-critical designs, enabling them to achieve a high SNR - as required, for example, by digital amplifier ICs. Designers can also benefit from more accurate models which are supplied in the new BSIM4 format. With this, the chances for achieving first-time-right implementation of complex analogue circuits are significantly improved.
X-FAB adds, “X-FAB has been setting the benchmark for low-noise performance in its 350 nm technology for many years. We are proud to now also offer industry-leading low-noise devices via our 180 nm XH018 platform. By adding just one extra mask layer, all three ultra-low-noise transistors can be incorporated into noise-sensitive circuit designs.”
The XH018 process design kit (PDK) is available for new designs. Noise parameters are included within the device models to facilitate an accurate simulation of the noise behavior of a circuit.