RF-to-BB-current-reuse wideband receiver with a single-MOS pole-zero LPF

Abstract

A single-MOS pole-zero lowpass filter for use in a single-ended-input current-reuse wideband receiver having a stacked RF-to-BB front end adapted to receive and process an RF signal to generate an N-phase BB signal, the lowpass filter being adapted to filter the N-phase BB signal, the lowpass filter having a lowpass input impedance for high stopband rejection at low voltage headroom consumption. The lowpass filter is arranged with one active MOS M LPF and one self-biased MOS M L ; M LPF creates complex poles and two stopband zeros to boost the stopband rejection; M L provides BB current-to-voltage conversion and common-mode feedback to alleviate tradeoff between voltage headband and BB gain; and M L is diode-connected to enable the generated BB signal to be copied to a next HR stage.

We claim: 
     
       1. A single-ended-input current-reuse wideband receiver, comprising:
 a stacked RF-to-BB front end adapted to receive and process an RF signal to generate an N-phase BB signal, the front end including: 
 a single-MOS pole-zero lowpass filter, and a replica bias circuit, to filter the N-phase BB signal, the lowpass filter having a lowpass input impedance for high stopband rejection at low voltage headroom consumption, 
 wherein 
 the lowpass filter is arranged with one active MOS M LPF  and one self-biased MOS M L , 
 M LPF  creates complex poles and two stopband zeros to boost the stopband rejection, 
 M L  provides BB current-to-voltage conversion and common-mode feedback to alleviate tradeoff between voltage headband and BB gain, and 
 M L  is diode-connected to enable the generated BB signal to be copied to a next HR stage. 
 
     
     
       2. The receiver as set forth in  claim 1 , wherein M LPF  and M L  are thick-oxide MOS. 
     
     
       3. The receiver as set forth in  claim 1 , wherein M LPF  and M L  are increased to reduce 1/f noise. 
     
     
       4. The receiver as set forth in  claim 1 , wherein the single-MOS pole-zero lowpass filter in current-mode has a current source connected between drain and source of M LPF  to provide in-band noise shaping when operated with a plurality of parallel N-path active mixers which process the RF signal by performing amplification, harmonic-recombination down-conversion, and baseband (BB) filtering on the RF signal, such that output noise has a bandpass shape. 
     
     
       5. The receiver as set forth in  claim 1 , wherein the input impedance of the single-MOS pole-zero lowpass filter has a peak response around cutoff to enhance its filtering profile and avoid fast roll-off when translated to RF. 
     
     
       6. The receiver as set forth in  claim 1 , wherein current-mode filtering at input and output nodes of the single-MOS pole-zero lowpass filter alters passband gain to ease tradeoff between in-/out-of-band linearity. 
     
     
       7. The receiver as set forth in  claim 1 , wherein the stopband zeros are at approximately 150-MHz offset to filter out (1) LO-to-IF leakage for targeted RF bandwidth and (2) GSM850/900 bands when the receiver is operated up to approximately 710 MHz for IEEE 802.11af. 
     
     
       8. A single-MOS pole-zero lowpass filter for use in a single-ended-input current-reuse wideband receiver having a stacked RF-to-BB front end adapted to receive and process an RF signal to generate an N-phase BB signal, the lowpass filter being adapted to filter the N-phase BB signal, the lowpass filter having a lowpass input impedance for high stopband rejection at low voltage headroom consumption,
 wherein 
 the lowpass filter is arranged with one active MOS M LPF  and one self-biased MOS M L , 
 M LPF  creates complex poles and two stopband zeros to boost the stopband rejection, 
 M L  provides BB current-to-voltage conversion and common-mode feedback to alleviate tradeoff between voltage headband and BB gain, and 
 M L  is diode-connected to enable the generated BB signal to be copied to a next HR stage. 
 
     
     
       9. The single-MOS pole-zero lowpass filter as set forth in  claim 8 , wherein M LPF  and M L  are thick-oxide MOS. 
     
     
       10. The single-MOS pole-zero lowpass filter as set forth in  claim 8 , wherein M LPF  and M L  are increased to reduce 1/f noise. 
     
     
       11. The single-MOS pole-zero lowpass filter as set forth in  claim 8 , wherein the lowpass filter in current-mode has a current source connected between drain and source of M LPF  to provide in-band noise shaping when operated with a plurality of parallel N-path active mixers which process the RF signal by performing amplification, harmonic-recombination down-conversion, and baseband (BB) filtering on the RF signal, such that output noise has a bandpass shape. 
     
     
       12. The single-MOS pole-zero lowpass filter as set forth in  claim 8 , wherein the input impedance of the lowpass filter has a peak response around cutoff to enhance its filtering profile and avoid fast roll-off when translated to RF. 
     
     
       13. The single-MOS pole-zero lowpass filter as set forth in  claim 8 , wherein current-mode filtering at input and output nodes of the lowpass filter alters passband gain to ease tradeoff between in-/out-of-band linearity. 
     
     
       14. The single-MOS pole-zero lowpass filter as set forth in  claim 8 , wherein the stopband zeros are at approximately 150-MHz offset to filter out (1) LO-to-IF leakage for targeted RF bandwidth and (2) GSM850/900 bands when employed in a receiver operating up to approximately 710 MHz for IEEE 802.11af. 
     
     
       15. A single-ended-input current-reuse wideband receiver, comprising:
 a stacked RF-to-BB front end adapted to receive and process an RF signal to generate an N-phase BB signal, the front end including: 
 a single-MOS pole-zero lowpass filter, and a replica bias circuit, to filter the N-phase BB signal, the lowpass filter having a lowpass input impedance for high stopband rejection at low voltage headroom consumption, 
 wherein 
 the lowpass filter is arranged with: 
 means for creating complex poles and two stopband zeros to boost the stopband rejection, 
 means for providing BB current-to-voltage conversion and common-mode feedback to alleviate tradeoff between voltage headband and BB gain, and 
 means for enabling the generated BB signal to be copied to a next HR stage.