A CMOS low-power variable-gain amplifier with RSSI for a noncoherent low data rate IR-UWB receiver

A low-power variable-gain amplifier (VGA) with integrated received signal strength indicator (RSSI) for a low data-rate impulse radio ultra-wideband (IR-UWB) receiver is designed and implemented in a CMOS 0.18 µm technology. The VGA achieves a gain range from −9 dB to 63 dB and bandwidth from 31 to 187 MHz. An input P1dB of −15.4 dBm is achieved at zero-dB gain. The RSSI has a dynamic range more than 70 dB. The RSSI linearity error is within ±1.2 dB for an input power from −77.5 dBm to −36.2 dBm. The VGA with integrated RSSI draws 5.4 mA from a 1.8V single supply and the test chip occupies an area of 970 µm × 750 µm, including two huge output buffers and digital gain control circuit.