Multi-range transconductor and method of operation

1. A method for tuning a transconductor, comprising:

receiving a digital value;

determining a bit value for a selected bit of the digital value;

selecting a tuning range for a transconductor based on the bit value; and

tuning the transconductor within the selected range based on any remaining bits in the digital value;

wherein:

the transconductor comprises a first transconductor and a second transconductor;

selecting the tuning range comprises selecting a gain for the first transconductor and a gain range for the second transconductor; and

tuning the transconductor comprises:

producing an output current of the transconductor using an output current of the first transconductor and an output current of the second transconductor; and

tuning a gain of the second transconductor within the gain range based on the remaining bits of the digital value.

2. The method of claim 1 , wherein selecting the tuning range comprises selecting a resistor from a plurality of resistors.

3. The method of claim 1 , wherein tuning the transconductor comprises:

converting the remaining bits into an analog signal; and

tuning the transconductor based on the analog signal.

4. The method of claim 1 , further comprising:

selecting an additional bit of the digital value; and

selecting a subrange within the range based on the value of the additional bit.

5. The method of claim 1 , wherein the transconductor is used to form a selected one of a filter, amplifier, mixer, integrator, or charge pump.

6. A transconductor circuit, comprising:

a digital-to-analog module operable to receive a digital value and to determine a bit value for a selected bit of the digital value;

a digital control module operable to select a tuning range for a transconductor based on the bit value; and

an analog control module operable to tune the transconductor within the selected range based on any remaining bits in the digital values

wherein:

the transconductor comprises a first transconductor and a second transconductor, each transconductor producing a respective output current, wherein an output current of the transconductor is produced using the output currents of the first and second transconductors;

the digital control module is further operable to select the tuning range by selecting a gain for the first transconductor and a gain range for the second transconductor; and

the analog control module is further operable to tune a gain of the second transconductor within the rain range based on the remaining bits of the digital value.

7. The circuit of claim 6 , wherein the digital control module is further operable to select the tuning range by selecting a resistor from a plurality of resistors.

8. The circuit of claim 6 , wherein:

the digital-to-analog module is further operable to convert the remaining bits into an analog signal; and

the analog control module is further operable to tune the transconductor based on the analog signal.

9. The circuit of claim 6 , wherein:

the digital-to-analog module is further operable to select an additional bit of the digital value; and

the digital control module is further operable to select a subrange within the range based on the value of the additional bit.

10. The circuit of claim 6 , wherein the transconductor is used to form a selected one of a filter, amplifier, mixer, integrator, or charge pump.

11. A circuit, comprising:

a first transconductor;

a second transconductor coupled to the first transconductor such that the first and second transconductors are operable to produce a combined output current from respective output currents of the first and second transconductors;

a digital-to-analog module operable to:

receive a digital value;

extract one or more bits from the digital value; and

convert the remaining bits of the digital value into an analog signal;

a digital control module operable to:

receive the one or more bits as a digital signal; and

select a gain for the first transconductor and a gain range for the second transconductor based on the digital signal; and

an analog control module operable to:

receive the analog signal; and

tune a gain of the second transconductor within the gain range based on the analog signal.

12. The circuit of claim 11 , wherein the digital control module selects a gain for the first transconductor and a gain range for the second transconductor at least in part based on a selected bit of the digital signal.

13. The circuit of claim 11 , wherein the digital control module selects the gain of the first transconductor and the gain range of the second transconductor by selecting one of a plurality of resistors.

14. The circuit of claim 11 , wherein the circuit is used to form a selected one of a filter, amplifier, mixer, integrator, or charge pump.

15. A computer readable medium storing software, the software when executed operable to perform:

receiving a digital value;

determining a bit value for a selected bit of the digital value;

selecting a tuning range for a transconductor based on the bit value; and

tuning the transconductor within the selected range based on any remaining bits in the digital value;

wherein:

the transconductor comprises a first transconductor and a second transconductor;

selecting the tuning range comprises selecting a gain for the first transconductor and a gain range for the second transconductor; and

tuning the transconductor comprises:

producing an output current of the transconductor using an output current of the first transconductor and an output current of the second transconductor; and

tuning a gain of the second transconductor within the gain range based on the remaining bits of the digital value.

16. The computer readable medium of claim 15 , wherein selecting the tuning range comprises selecting a resistor from a plurality of resistors.

17. The computer readable medium of claim 15 , wherein tuning the transconductor comprises:

converting the remaining bits into an analog signal; and

tuning the transconductor based on the analog signal.

18. The computer readable medium of claim 15 , wherein the software is further operable to perform:

selecting an additional bit of the digital value; and

selecting a subrange within the range based on the value of the additional bit.

19. The computer readable medium of claim 15 , wherein the transconductor is used to form a selected one of a filter, amplifier, mixer, integrator, or charge pump.

20. A system, comprising:

means for receiving a digital value;

means for determining a bit value for a selected bit of the digital value;

means for selecting a tuning range for a transconductor based on the bit value; and

means for tuning the transconductor within the selected range based on any remaining bits in the digital value;

wherein:

the transconductor comprises a first transconductor and a second transconductor;

the means for selecting the tuning range further selects a gain for the first transconductor and a gain range for the second transconductor; and

the means for tuning the transconductor further:

produces an output current of the transconductor using an output current of the first transconductor and an output current of the second transconductor; and

tunes a gain of the second transconductor within the gain range based on the remaining bits of the digital value.