公开(公告)号：US20190006991A1

公开(公告)日：2019-01-03

申请号：US15639267

申请日：2017-06-30

Applicant: SILICON LABORATORIES INC.

Inventor： TIAGO MARQUES ,  JOHN KHOURY

IPC: H03B5/36 ,  H03B5/04

CPC classification number: H03B5/366 ,  H03B5/04 ,  H03B5/364 ,  H03B2200/004 ,  H03B2200/005 ,  H03B2200/0068 ,  H03B2201/0208 ,  H03B2201/0266

Abstract: A crystal driver circuit for driving a crystal to oscillate at a resonant frequency including an amplifier having an input coupled to an amplifier input node and having an output coupled to an amplifier output node, a current source that provides a core bias current to the amplifier, a first tune capacitor coupled between the amplifier output node and a reference node, and a second tune capacitor coupled between the amplifier input node and the reference node. The first tune capacitor has a first capacitance that is greater than a second capacitance of the second tune capacitor by a capacitance offset that reduces frequency shift during operation. The first and second capacitances have a combined capacitance that achieves an oscillating signal having a target frequency.