Differential source follower having 6dB gain with applications to WiGig baseband filters
US8803596B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 14, 2013 |
| Grant date | Aug 12, 2014 |
| Priority date | — |
| Expiry date | Oct 14, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49016
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Sallen-Key filters require an operational amplifier with a large input impedance and a small output impedance to meet the external filter characteristics. This invention eliminates the need for internal feedback path for stability and increases the gain of a source follower which has characteristics matching the operational amplifier in the Sallen-Key filter. The source follower provides 6 dB of AC voltage gain and is substituted for the operational amplifier in the Sallen-Key filter. The Sallen-Key filter requires a differential configuration to generate all the required signals with their complements and uses these signals in a feed forward path. Furthermore, since the source follower uses only two n-channel stacked devices, the headroom voltage is maximized to several hundred millivolts for a 1.2V voltage supply in a 40 nm CMOS technology. Thus, the required 880 MHz bandwidth of the Sallen-Key filter can be easily met using the innovative source follower.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.