Radio frequency (RF) filters are one of the key building blocks in modern microelectronic digital communication systems that use a narrow frequency band with strong interferers nearby. The objective of this thesis is to explore the better DR performance of RF filters using the Q-enhanced LC filter. It takes a divide-and-conquer method by designing
1. A new simple pseudo-differential pair (PDP) for input gm stage. It is the fastest, high-linearity, low-distortion, and wide-range constant-gm design reported to date. This has been applied in the final filter tape-out and has proven to be effective experimentally.
2. A new tunable discrete inductor (TDL) to achieve two-level inductance with the same real estate that can be used to expand the filtering frequency range. This has been verified experimentally.
3. A new tunable discrete capacitor (TDC) to achieve high linearity over wide terminal voltage swing range. This has been verified through simulation.
4. A new systematic way to achieve synchronized gain, center frequency, and filtering Q tuning capability for Q-enhanced LC filters. It has been verified through simulation.
In order to verify the concept, a 900 MHz filter is designed and fabricated with National Semiconductor Company (NSC)'s standard 0.18 um digital epi-substrate CMOS technology, and packaged with NSC's LLP-28. The measurement results show that with filter Q of 17 at 845 MHz, the 1 dB compression point is measured to be
+4 dBm, IIP3 to be +16 dBm with a peak noise floor of -154 dB/Hz, spurious free dynamic range (SFDR) to be 71 dB. With filter Q of 70 over a 20 MHz BW, the 1 dB compression point is measured to be -9.5 dBm, IIP3 to be +7 dBm with a peak noise floor of -141 dB/Hz, SFDR to be 57 over 20 MHz BW. This filter uses between 56 and 60 mA with a power supply of 1.8 V due to the low-Q (Q~1) of inductor. It is the RF filter with the highest DR in the published literature. The DR can be even
higher if inductor Q can be improved as DR is proportional to Q^2.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/7169 |
| Date | 13 July 2005 |
| Creators | Li, Shengyuan |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
| Format | 2443091 bytes, application/pdf |
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