High-Linearity Bottom-Plate Mixing Technique With Switch Sharing for N-path Filters/Mixers
High-Linearity Bottom-Plate Mixing Technique With Switch Sharing for N-path Filters/Mixers
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DOI：
10.1109/jssc.2018.2878812
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发表时间：
2019-02-01
影响因子：
5.4
通讯作者：
Nauta, Bram
中科院分区：
文献类型：
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作者：
Lien, Yuan-Ching;Klumperink, Eric A. M.;Nauta, Bram
针对高线性度和高压缩要求，提出了一种用于无表面声波（SAW）频分双工（FDD）无线电接收机的四路滤波器/混频器。底板混合技术通过减少MOSFET开关的栅源电压调制来改善线性度。差动底板混合允许开关共享，使有效开关电阻减半，以减少漏源电压调制。第一个四路开关- rc滤波器级具有底板混合和共享开关，在LO频率附近提供二阶电压域rf带通滤波。在第二级交叉耦合开关- rc四路级中，额外的带外抑制与V-I转换和零中频下变频相结合，为带外干扰提供了低欧姆高线性电流路径。采用28纳米CMOS技术制作的原型芯片实现了带外IIP3为+44 dBm， IIP2为+90 dBm，阻塞器1 db增益压缩点为+13 dBm，阻塞器频率偏移为80 MHz。在这个偏置频率下，在0.7 ghz LO（即6和9 dB阻挡器噪声系数）下，0-dBm阻挡器的测量脱敏率仅为0.6 dB， 10-dBm阻挡器的测量脱敏率为3.5 dB。该芯片在0.1-2 GHz的lo频率下消耗38-96 mW，占用0.49 mm(2)的有效面积。
A four-path filter/mixer for surface acoustic wave (SAW)-less frequency division duplex (FDD) radio receivers is proposed, targeting high linearity and compression requirements. A bottom-plate mixing technique improves linearity by reducing the gate-source voltage modulation of the MOSFET switches. Differential bottom-plate mixing allows for switch sharing which halves the effective switch resistance to reduce drain-source voltage modulation. The first four-path switch-RC filter stage with bottom-plate mixing and a shared switch renders 2nd-order voltage-domain RF-bandpass filtering around the LO frequency. Extra out-of-band rejection is implemented combined with V-I conversion and zero-IF frequency down-conversion in the second cross-coupled switch-RC four-path stage, which offers a low-ohmic high-linearity current path for out-of-band interferers. A prototype chip fabricated in a 28-nm CMOS technology achieves an out-of-band IIP3 of +44 dBm, IIP2 of +90 dBm and blocker 1-dB gain-compression point of +13 dBm for a blocker frequency offset of 80 MHz. At this offset frequency, the measured desensitization is only 0.6 dB for a 0-dBm blocker, and 3.5 dB for a 10-dBm blocker at 0.7-GHz LO (i.e., 6- and 9-dB blocker noise figure). The chip consumes 38-96 mW for LO-frequencies of 0.1-2 GHz and occupies an active area of 0.49 mm(2).