德国ACAM公司提供各种TDC芯片，其中TDC-GPX是其提供的最高端的芯片，即便如此这款芯片也是在2005和2006之间推出的，此后一直没有新的类似芯片推出。“小众”应用的芯片，是因为用量少，所以不需要出多种型号的“新”芯片，还是因为多年来此领域并无大的创新而无新芯片推出？！ 对于此款高端TDC芯片的应用场合，ACAM官方给出以下描述：
“The TDC-GPX is the most powerful member in ACAM‘s Time-to-Digital Converter product line. It is designed for applications that require fast measurement rates, best single shot precision and highest pulse pair resolution for measurement and digitization of time intervals. According to that, the device perfectly meets the requirements for technically sophisticated industrial, medical, and scientific application, like laser scanners, time-of-flight spectroscopy, coincidence measurements, PET-scanners, automatic test equipment.The TDC-GPX is the most powerful member in acam‘s Time-to-Digital Converter product line. It is designed for applications that require fast measurement rates, best single shot precision and highest pulse pair resolution for measurement and digitization of time intervals. According to that, the device perfectly meets the requirements for technically sophisticated industrial, medical, and scientific application, like laser scanners, time-of-flight spectroscopy, coincidence measurements, PET-scanners, automatic test equipment.”
附件是TDC-GPX的手册，该芯片分为四种工作模式，用户可以进行配置。第一种工作模式是我们需要用到的模式即I-Mode。
I-Mode：8通道，LVTTL输入，81ps精度
G-Mode：2通道，差分LVPECL输入，40ps精度
R-Mode：2通道，差分LVPECL输入，27ps精度
M-Mode：2通道，差分LVPECL输入，10ps精度
