Integration of filters using on-chip transformers for RF and wireless applications

• US 7,199,443 B2
• Filed: 02/21/2003
• Issued: 04/03/2007
• Est. Priority Date: 02/22/2002
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Elsharawy, Badawy
• Primary Examiner(s): LEE, HSIEN MING
• Application Number:
  US10/505,258
• Publication Number:
  US 20050095791A1
• Time in Patent Office: 1,502 Days
• Field of Search: 257/528, 257/532, 257/E27.001, 257/E27.017, 257/E27.024, 438/381, 455/73, 455/80, 455/280, 455/272
• US Class Current: 257/528
• CPC Class Codes: H03H 7/09 Filters comprising mutual inductance
• CPC Class Codes: H03H 7/1775 Parallel LC in shunt or branch path H03H7/1791 takes precedence

Abstract

A band pass filter (114) is formed on an integrated circuit (IC) chip (102). Such band pass filter (114) may be used in a RF or wireless communication device, such as a mobile phone or a personal data assistant (PDA). The band pass filter (114) includes a transformer (202 and 204) made of a pair of metallic spirals formed on the IC chip. The metallic spirals may have substantially square or rectangular overall shape, and may be fabricated using copper. The metallic spirals may be co-planar and inter-wound or may be stacked, one on top of the other, and separated by a dielectric layer. The transformer (202 and 204) is capable of receiving an input signal, and providing high pass filtering to the input signal. The band pass filter (114) also includes a capacitor (226, 2; 230 and 232) that is capable of receiving the input signal and providing low pass filtering in conjunction with an inductance of the transformer (202 and 204). The band pass filter (114) provides band pass filtering through cascading said high pass and low p filtering.

Claims

1. A band pass filter formed on an integrated circuit (IC) chip, said band pass filter comprising:

a transformer capable of receiving an input signal and providing high pass filtering, said transformer comprising at least a pair of metallic spirals formed on the IC chip; and

a capacitor capable of receiving said input signal and providing low pass filtering in conjunction with an inductance of the transformer,

wherein said band pass filter provides band pass filtering through cascading said high pass and low pass filtering.

2. The band pass filter of claim 1, further comprising a plurality of band pass filter stages, each band pass filter stage comprising a capacitor and a transformer comprising a pair of metallic spirals formed on the IC chip, wherein said band pass filter stages are cascaded to form the band pass filter.

3. The band pass filter of claim 1, wherein said metallic spirals comprise copper spirals.

4. The band pass filter of claim 1, wherein the transformer comprises a pair of transformers arrayed in series, wherein each transformer comprises a pair of metallic spirals.

5. The band pass filter of claim 1, wherein the metallic spirals are co-planer and have been inter-wound to form the transformer on the IC chip.

6. The band pass filter of claim 1, wherein the metallic spirals are stacked, one on top of the other, to form the transformer on the IC chip.

7. The band pass filter of claim 6, wherein the metallic spirals are separated by a dielectric material disposed therebetween.

8. The band pass filter of claim 7, wherein the dielectric material comprises silicon dioxide.

9. The band pass filter of claim 1, wherein communication circuitry is formed on the same IC chip as the transformer and the capacitor.

10. The band pass filter of claim 1, wherein a transformation ratio of the transformer is between approximately 1:

1 and approximately 1;

2.

11. The band pass filter of claim 1, Wherein the IC chip comprises a silicon substrate.

12. The band pass filter of claim 1, wherein the metallic spirals have a substantially rectangular or square overall shape.

13. A communication system-on-chip (SOC) comprising communication circuitry and a band pass filter formed on an integrated circuit (IC) chip, said band pass filter comprising:

a transformer capable of receiving an input signal and providing high pass filtering, said transformer comprising at least a pair of metallic spirals formed on the IC chip; and

a capacitor capable of receiving said input signal and providing low pass filtering in conjunction with an inductance of the transformer, wherein said band pass filter provides band pass filtering through cascading said high pass and low pass filtering.

14. The communication SOC of claim 13, wherein the band pass filter further comprises a plurality of band pass filter stages, each band pass filter stage comprising a capacitor and a transformer comprising a pair of metallic spirals formed on the IC chip, wherein said band pass filter stages are cascaded to form the band pass filter.

15. The communication SOC of claim 13, wherein said metallic spirals comprise copper spirals.

16. The communication Soc of claim 13, wherein the transformer comprises a pair of transformers arrayed in series, wherein each transformer comprises a pair of metallic spirals.

17. The communication SOC of claim 13, wherein the metallic spirals are co-planer and have been inter-wound to form the transformer on the IC chip.

18. The communication SOC of claim 13, wherein the metallic spirals are stacked, one on top of the other, to form the transformer on the IC chip.

19. The communication SOC of claim 18, wherein the metallic spirals are separated by a dielectric material disposed therebetween.

20. The communication SOC of claim 19, wherein the dielectric material comprises silicon dioxide.

21. The communication SOC of claim 13, wherein a transformation ratio of the transformer is between approximately 1:

1 and approximately 1;

2.