发明名称 |
Phase noise reduction in voltage controlled oscillators |
摘要 |
A voltage controlled oscillator (VCO), a method of designing a voltage controlled oscillator, and a design structure comprising a semiconductor substrate including a voltage controlled oscillator are disclosed. In one embodiment, the VCO comprises an LC tank circuit for generating an oscillator output at an oscillator frequency, and an oscillator core including cross-coupled semiconductor devices to provide feedback to the tank circuit. The VCO further comprises a supply node, a tail node, and a noise by-pass circuit connected to the supply and tail nodes, in parallel with the tank circuit and the oscillator core. The by-pass circuit forms a low-impedance path at a frequency approximately twice the oscillator frequency to at least partially immunize the oscillator core from external noise and to reduce noise contribution from the cross-coupled semiconductor devices. |
申请公布号 |
US9330214(B2) |
申请公布日期 |
2016.05.03 |
申请号 |
US201414152330 |
申请日期 |
2014.01.10 |
申请人 |
International Business Machines Corporation |
发明人 |
Valdes-Garcia Alberto;Sadhu Bodhisatwa |
分类号 |
H03B5/08;G06F17/50;H03B1/00;H03B5/12 |
主分类号 |
H03B5/08 |
代理机构 |
Scully, Scott, Murphy & Presser, P.C. |
代理人 |
Scully, Scott, Murphy & Presser, P.C. ;Alexanian Vasken |
主权项 |
1. A voltage controlled oscillator (VCO) comprising:
an LC tank circuit for generating an oscillator output signal at an oscillator frequency (fo); an oscillator core including first and second cross-coupled semiconductor devices connected to the tank circuit to provide regenerative feedback to the tank circuit to help maintain the oscillator output stable; a supply node connected to the tank circuit for connecting the VCO to a voltage source; a tail node connected to the oscillator core for connecting the VCO to a current source; and a noise by-pass circuit having a first end connected to the supply node and a second end connected to the tail node and forming a low-impedance by-pass circuit connecting the supply node and the tail node, in parallel with the LC tank circuit and the oscillator core, at a frequency approximately twice the oscillator frequency to at least partially immunize the oscillator core from external noise and to reduce noise contribution from the cross-coupled semiconductor devices. |
地址 |
Armonk NY US |