On Die Termination (ODT) DDR

Signal Reflection

In the data line and chip connection point impedance is not the same, generate electrical signals reflected, become noise, in the high-speed circuit has great influence.

As shown below, there are two dram on the bus, one receiving signal, one reflection, and the reflected signal will affect the received DRAM. The motherboard has a termination resistor to absorb the reflected signal.

odt:on die Termination

Use the ODT resistor to end the signal from the bus to the DRAM, no more reflections.