CML、LVPECL和LVDS

1、Current-mode drivers  VS Voltage-mode drivers

2、CML（Current Mode Logic）

CML drivers that are built from an open-drain differential pair and a voltage-controlled current source using NMOS transistors.

The outputs (Output+ and Output–) require pullup resistors to VDD because the NMOS transistor can drive only falling edges efficiently and needs the pullups to help drive rising edges.

The output voltage swing is load dependent.

3、LVDS（Low Voltage Differential Signals）

4、LVPECL（Low Voltage PECL）

5、VML（Voltage Mode Logic）

The output swing of VML interfaces is independent of the load impedance.

6、互连

6.1、DC Coupling

6.2、AC Coupling

Interfacing Between LVPECL, VML, CML, and LVDS Levels

Introduction to LVDS, PECL, and CML