This paper presents a 20-Gb/s automatic gain control (AGC) amplifier in a 0.18-μm SiGe BiCMOS for high-speed applications. The proposed AGC amplifier compactly consists of a folded Gilbert variable-gain amplifier (VGA), a post amplifier (PA), a 50-Ω output buffer, and AGC loop including an open-loop peak detector (PD), a RC low-pass filter (LPF), and an error amplifier (EA). The AGC amplifier achieves the broadband characteristic by utilizing inductive peaking and capacitive degeneration as well as f_T-doubler techniques to overcome the large parasitic capacitances. The proposed AGC circuits together with a linear VGA exhibits a wide gain control range of 45 dB for the received signal strength indication (RSSI). The measured AGC amplifier achieves a maximum gain of 21 dB and a -3-dB bandwidth (BW) of 20.6 GHz, which can support up to 25.4-Gb/s data rate. For the pseudorandom bit sequence (PRBS) length 2³¹–1 with a bit-error rate (BER) of 10⁻¹² at 20 Gb/s, the measured input dynamic range is 26 dB (20–400mV_pp) and the peak-to-peak data jitter is less than 8 ps. The AGC amplifier consumes a power of 160 mW from a 3.3-V supply voltage and occupies an area of 850 μm × 850 μm.

本文介绍了用于高速应用的 0.18-μm SiGe BiCMOS 中的 20-Gb/s 自动增益控制 (AGC) 放大器。所提出的 AGC 放大器紧凑地由折叠吉尔伯特可变增益放大器 (VGA)、后置放大器 (PA)、50Ω 输出缓冲器和 AGC 环路组成，该环路包括开环峰值检测器 (PD)、RC低-通滤波器 (LPF) 和误差放大器 (EA)。AGC 放大器通过利用电感峰值和电容退化以及f _T实现宽带特性- 倍增技术来克服大寄生电容。建议的 AGC 电路与线性 VGA 一起展示了 45 dB 的宽增益控制范围，用于接收信号强度指示 (RSSI)。测得的 AGC 放大器最大增益为 21 dB，-3-dB 带宽 (BW) 为 20.6 GHz，可支持高达 25.4-Gb/s 的数据速率。对于长度为 2 ³¹ –1 且误码率 (BER) 为 10 ^-12 在 20 Gb/s的伪随机比特序列 (PRBS) 而言，测得的输入动态范围为 26 dB (20–400mV _pp )，峰值 -峰值数据抖动小于 8 ps。AGC 放大器在 3.3V 电源电压下消耗 160 mW 的功率，并占据 850 μm × 850 μm 的面积。