High dynamic range time-varying integrated receiver for elimination of off-chip filters

• US 7,460,844 B2
• Filed: 01/28/2005
• Issued: 12/02/2008
• Est. Priority Date: 01/28/2004
• Status: Active Grant

• Current Assignee: MediaTek, Inc.
• Original Assignee: Axiom Microdevices Incorporated (Skyworks Solutions Incorporated)
• Inventors: Magoon, Rahul, Molnar, Alyosha
• Primary Examiner(s): NGUYEN, SIMON
• Application Number:
  US11/046,023
• Publication Number:
  US 20050164669A1
• Time in Patent Office: 1,404 Days
• Field of Search: 455/293, 455/330, 455313-326, 455/333, 455334-340
• US Class Current: 455/130
• CPC Class Codes: H03D 2200/0088 Reduction of intermodulation, nonlinearities, adjacent channel interference; intercept points of harmonics or intermodulation products
• CPC Class Codes: H03D 7/1441 using field-effect transistors H03D7/145 takes precedence
• CPC Class Codes: H03D 7/1458 Double balanced arrangements, i.e. where both input signals are differential
• CPC Class Codes: H03D 7/1466 Passive mixer arrangements
• CPC Class Codes: H03D 7/1483 comprising components for selecting a particular frequency component of the output
• CPC Class Codes: H03D 7/165 at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002
• CPC Class Codes: H03H 19/004 Switched capacitor networks
• CPC Class Codes: H04B 1/006 using switches for selecting the desired band H04B1/0057 takes precedence
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence

Abstract

A quadrature mixer with an LO input is provided. The quadrature mixer receives a signal having a frequency F_LO and a signal input having a frequency F_SIG, and has an output that comprises an output impedance that is high at frequencies of |F_LO−F_SIG | and |F_LO+F_SIG| and low at other. A mixer coupled to the output impedance interacts with the output impedance such that an impedance presented at the signal input is high for signals at F_SIG if F_SIG is a predetermined signal frequency, and low at other frequencies.

Claims

1. A receiver circuit comprising:

a quadrature passive mixer having an input and an output;

one or more output impedances coupled to the output of the quadrature passive mixer wherein an input impedance of the quadrature passive mixer provides a band-pass response;

a low noise amplifier (LNA) having an input and an output coupled to the quadrature passive mixer, the LNA configured to provide substantially linear transconductance over a predetermined input range; and

wherein the LNA and the quadrature passive mixer are configured so that a band-pass mixer input impedance response is presented to the output of the LNA so as to substantially reduce a LNA voltage gain for unwanted signals presented to the LNA input.

2. The receiver of claim 1, wherein the LNA is a common source amplifier and includes source degeneration.

3. The receiver of claim 2, wherein:

LO inputs of one or more switches of the quadrature passive mixer are driven by buffers through series-resonant LC structures;

the series-resonant LC structures are tuned to an LO frequency; and

a peak-to-peak swing at the switches is enhanced beyond a breakdown voltage of the buffer.

4. The receiver of claim 1, wherein the LNA is a differential amplifier.

5. The receiver of claim 1, wherein:

a frequency of operation corresponds to a channel in a wireless voice communications band;

the linear transconductance of the LNA input reduces degradation of an in-band signal in the presence of an out-of band signal; and

the band-pass response of the mixer attenuates the out-of band signal so as to prevent the out-of-band signal from degrading the in-band signal at the output of the LNA.

6. The receiver of claim 5, wherein the receiver is selected from one or more of the group comprising a low intermediate frequency receiver and a direct conversion receiver.

7. The receiver of claim 5, wherein:

the in-band signal corresponds to a channel in a GSM band;

the LNA input is sufficiently linear so as to not significantly degrade sensitivity-level wanted signals in the presence of out-of band signals;

the band-pass action of the mixer attenuates out-of-band signals to prevent out-of-band signals from degrading wanted signals at the output of the LNA.

8. The receiver of claim 1, wherein the quadrature passive mixer further comprises:

a plurality of NFETs and PFETs; and

wherein the NFETs and PFETs are driven with substantially differential signals.

9. The receiver of claim 1, wherein the quadrature passive mixer further comprises:

a plurality of FET switches; and

wherein two or more of the FET switches are biased to approximately a same voltage.

10. The receiver of claim 1, wherein the quadrature passive mixer further comprises:

a plurality of FET switches; and

wherein two or more of the FET switches are biased to approximately the same voltage.

11. A receiver circuit comprising:

a mixer having an input and an output;

one or more output impedances coupled to the output of the mixer wherein an input impedance of the mixer provides a band-pass response; and

a low noise amplifier (LNA) having an input and an output coupled to the mixer, the LNA configured to provide substantially linear transconductance over a predetermined input range.

12. The receiver of claim 11, wherein the linear transconductance of the LNA input reduces degradation of an in-band signal in the presence of an out-of band signal.

13. The receiver of claim 11, wherein the mixer further comprises:

a plurality of NFETs and PFETs; and

wherein the NFETs and PFETs are driven with substantially differential signals.

14. A receiver circuit comprising:

a quadrature passive mixer having an input and an output;

means coupled to the output of the quadrature passive mixer for providing a band-pass response of an input impedance of the quadrature passive mixer; and

a low noise amplifier (LNA) having an input and an output coupled to the quadrature passive mixer, the LNA configured to provide substantially linear transconductance over a predetermined input range.

15. The receiver of claim 14, wherein the LNA and the quadrature passive mixer arc configured so that a band-pass mixer input impedance response is presented to the output of the LNAso as to substantially reduce a LNA voltage gain for unwanted signals presented to the LNA input.

16. The receiver of claim 14, wherein:

a frequency of operation corresponds to a channel in a wireless voice communications band;

the linear transconductance of the LNA input reduces degradation of an in-band signal in the presence of an out-of band signal.

17. A receiver circuit comprising:

a mixer having an input and an output;

one or more output impedances coupled to the output of the mixer providing an input impedance of the mixer with a band-pass response;

a low noise amplifier (LNA) having an input and an output and providing substantially linear transconductance over a predetermined input range coupled to the mixer; and

wherein a band-pass mixer input impedance response is presented to the output of the LNA.

18. The receiver of claim 17, wherein the quadrature passive mixer further comprises:

a plurality of NFETs and PFETs; and

wherein the NFETs and PFETs are driven with substantially differential signals.

19. The receiver of claim 17, wherein the quadrature passive mixer further comprises:

a plurality of FET switches; and

wherein two or more of the FET switches are biased to approximately the same voltage.

20. A receiver comprising:

a quadrature passive mixer having an input and an output and an input impedance and providing a band-pass response;

a low noise amplifier (LNA) having an input and an output coupled to the quadrature passive mixer, the LNA configured to provide substantially linear transconductance over a predetermined input range; and

wherein the LNA and the quadrature passive mixer are configured so that a band-pass mixer input impedance response is presented to the output of the LNA so as to substantially reduce a LNA voltage gain for unwanted signals presented to the LNA input.

21. The receiver of claim 20, wherein:

a frequency of operation corresponds to a channel in a wireless voice communications band;

the linear transconductance of the LNA input reduces degradation of an in-band signal in the presence of an out-of band signal; and

the band-pass response of the mixer attenuates the out-of band signal so as to prevent the out-of-band signal from degrading the in-band signal at the output of the LNA.