A phase-lock loop (PLL) filter architecture includes a first charge pump (508) and a second change pump (510). The second charge pump (510) operates in opposite phase of the first charge pump (508) in order to take away excess charge from the loop filter capacitor(s). By using a second charge pump as...http://www.google.se/patents/US6600351?utm_source=gb-gplus-sharePatent US6600351 - Loop filter architecture
