Why does BLVDS (Bus Low Voltage Differential Signaling) use a 10mA current source?
BLVDS can drive a heavily loaded bus with only 10 mA because it also minimizes the bus loading from other transceivers attached to the bus. Another benefit to the overall system is the low cost of termination and the low power dissipated at the termination. Bus LVDS does not require any active devices for the termination. Unlike GTL, SSTL, or TTL, Bus LVDS uses only 2 passive termination resistors. All other bus-driving technologies require a tightly regulated termination voltage, such as 1.5V for GTL+. This tight regulation adds substantial cost to the backplane design because of the required voltage control chips and passive components that surround the chips. However, why add voltage regulation when the Bus LVDS only requires that you have two passive resistors? A bus designer will determine the Bus LVDS termination resistor (RT) value by calculating the loaded impedance (ZL) of the bus. There are complex sets of variables that determine the ZL. The factors are spacing between the l
Related Questions
- What is the difference between LVDS (Low Voltage Differential Signaling) and BLVDS (Bus Low Voltage Differential Signaling)?
- What is the difference between BLVDS (Bus Low Voltage Differential Signaling) and MLVDS (Multipoint Low Voltage Signaling)?
- What is the advantage of Low Voltage Differential signaling?
