Title:
HIGH-SPEED SWITCHED-CAPACITOR RIPPLE-SMOOTHING FILTER FOR LOW JITTER PHASE-LOCKED LOOP
Document Type and Number:
WIPO Patent Application WO2005114837
Kind Code:
A3
Abstract:
A switched-capacitor ripple-smoothing filter (400) includes a first pair of capacitors (Co, Ce). The filter (400) is configured such that either capacitor in the first pair may be reset and have a terminal coupled to a first input port (P) and such that the remaining capacitor in the first pair is isolated from the first input port (P) and has the terminal coupled to a first output port (Voutp) while the other capacitor is being charged. The filter further includes a second pair of capacitors (CO, Ce), the filter being configured such that either capacitor in the second pair may be reset and have a terminal coupled to a second input port (N) and such that the remaining capacitor in the second pair is isolated from the second input port (N) and has the terminal coupled to a second output port (Voutn) while the other capacitor in the second pair is being charged. Advantageously, the filter is configured such that the capacitors (Co, Ce) in the first and second pair are reset responsive to the assertion of a single reset signal.
Inventors:
ZHU XIANG (US)
QU MING (US)
QU MING (US)
Application Number:
PCT/US2005/010946
Publication Date:
February 16, 2006
Filing Date:
March 31, 2005
Export Citation:
Assignee:
LATTICE SEMICONDUCTOR CORP (US)
International Classes:
H03H11/26; H03H19/00; H03L7/089; H03L7/093; (IPC1-7): H03K5/00; H03L7/06
Foreign References:
| US5598118A | 1997-01-28 | |||
| US6141541A | 2000-10-31 | |||
| US5973536A | 1999-10-26 |
Other References:
MAXIM ET AL: "A low-jitter...Loop Filter.", IEEE JOURNAL OF SOLID STATE CIRCUITS., vol. 36, no. 11, November 2001 (2001-11-01), pages 1673 - 1683
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