关于锁相环芯片的外部环路滤波电路的问题

一只小鱼儿

锁相环芯片的外部环路滤波电路接在了CPOUT管脚，手册上推荐该滤波电路需要靠近管脚放置，想请教一下，外部环路滤波电路如果不靠近CPOUT管脚放置，会有什么影响吗？

超級狗

. K9 n0 e! a% M1 H9 q+ N
CPOUT
* V4 p4 ~9 W2 s" e* v4 ?Charge-Pump Output. Connect a PLL loop filter as a shunt C and a shunt combination of series R and C.

超級狗

踢哀（TI）E2E 論壇
8 r5 b! U  m; R. _" E( qAs for the CPout pin, this is the charge pump output which can range from 0 to 2.5V, as it is powered by a 2.5V regulator. If this voltage falls below 0.5 V or goes above 2.0 V, then the Vtune lock detect will consider this unlocked. When the VCO is calibrated, this targes a voltage of around 1.2 volts, but this voltage can "tune" to adjust the VCO frequency.
: ]$ F- C  m  A9 F) {) f

一只小鱼儿

超級狗 发表于 2024-9-23 12:50
6 G% D6 q9 T% T6 ?踢哀（TI）E2E 論壇
0 Y& {( U4 c, G# k3 d5 X/ M% Y; _, f" xAs for the CPout pin, this is the charge pump output which can range from 0 to 2 ...

感谢，刚看TI的资料，这应该会对相位噪声有点影响。