Design Of A 2.45 GHz BT Power Amplifier Based On 22 Nm CMOS Process

With the advent of the Internet of Everything era,the status of Internet of Things services in people’s lives has gradually become irreplaceable,and the growing demand has gradually increased the communication capabilities of terminal equipment.Wireless Body Area Network(WBAN),as one of the core technologies of the Internet of Things,has been effectively applied to vehicle electronic equipment,short-distance data acquisition,industrial automation control,and medical and health fields.Bluetooth Low Energy(BLE)is the most widely used in WBAN because of its small size,low cost,and long transmission distance.As the core part of the BLE RF front-end,the Bluetooth(BT)RF power amplifier is also the module with the largest power consumption,and the circuit design is more difficult.How to ensure that the BT power amplifier meets the set radio frequency index,realize low power consumption and small size at the same time,has always been a key issue that chip designers pay attention to.Therefore,designing a BT power amplifier with low power consumption,high linearity,adjustable gain,and adjustable operating frequency for WBAN has good engineering application value.Based on the requirements of the BT protocol,this subject designs a BT RF power amplifier with low power consumption,high performance and adjustable gain using 22 nm CMOS technology.The RF power amplifier mainly includes three parts: amplifier circuit,bias circuit and on-chip balun,which can be applied to 2.45 GHz BT chip scenarios.The amplifying circuit of the BT power amplifier adopts a differential cascode structure to realize third-order non-linear cancellation,thereby improving the linearity of the power amplifier.The bias circuit uses an adaptive bias circuit to compensate for the influence of temperature and process angle changes on the circuit.At the same time,the MOS tube switch is used to control all the nodes that take the bias current to ensure that the leakage current is the smallest when the circuit is not working.Realize low power consumption of BT power amplifier.This topic also introduces the gain adjustment function of the power amplifier,which can flexibly control the gain of the power amplifier and change the output power through the digital signal.In addition,the output of the BT power amplifier also adopts the form of switched capacitors connected in parallel with the on-chip transformer to achieve broadband matching,and the capacitance value is changed through digital signal control,and then the operating frequency of the power amplifier is tuned to achieve a broadband operating range.The output end uses an on-chip balun with a turn ratio of 6:2 to complete the output impedance transformation,and at the same time realize the conversion from the differential double-ended signal to the antenna single-ended.The transformer was modeled and optimized using electromagnetic simulation software to minimize losses.Finally,the layout was drawn and the post-simulation was carried out.When the operating frequency range is 2.4 GHz ～2.48 GHz and the power supply voltage is 3.3 V,the static power consumption current is 22.3 m A,and the saturated output power and output 1dB compression point power of the power amplifier are respectively 14.8 dBm and 11.46 dBm,the third-order output intermodulation point is 24.9 dBm,the circuit gain is 16.85 dB,the input matching degree is-12.76 dB,and the maximum added efficiency of the power amplifier is 21.39%,a typical value for Thrid Order Intermodulation(IMD3)is-46 dBc,which meets the design requirements.