A novel programmable gain control low noise amplifier (PGCLNA) design for automatic gain control loop in BLE applications

Abstract

Bluetooth low energy (BLE) is a widely used short-range communication protocol and BLE receivers frequently encounter transient high-power RF (radio frequency) signals from antennas, leading to receiver saturation. To address this issue, this work proposes a 2.4 GHz programmable gain control low-noise amplifier (PGCLNA), which is a key element in an automatic gain control (AGC) system for BLE receiver applications. The proposed PGCLNA achieves discrete levels of gain using the g m -boosting technique by splitting the negative feedback. The proposed circuit is simulated in UMC 180 nm technology and the maximum gain achieved is 41.4 dB, with a step decrease of 15 dB in discrete levels. The gain variations do not degrade the performance of S11, which is always less than -16 dB. The noise figure (NF) is always minimum of 5.5 dB and in high gain mode, the minimum value of NF is 1.82 dB. The third-order intercept point (IIP3) is −7.621 dBm in the best circumstances and always remains above −10.69 dBm. These results are achieved by utilising 5.4 mW power at 1.8 V of supply voltage. The circuit occupies an area of 732 μm × 771 μm. The proposed PGCLNA design offers a solution to accommodate a wide range of input signals in BLE receivers, excellent gain control, low noise and robust performance characteristics, making it an essential component in an AGC system for BLE receiver applications.