LVPECL Emulated (LVPECLE33) Output Mode

LVPECL is derived from ECL and PECL and uses 3.3 V supply voltage. The following illustration shows an example of implementation using 93 Ω stub resistors with a 196 Ω parallel/differential termination at the driver and a 100 Ω differential termination at the receiver. The termination values at the driver should be optimized to match the effective differential impedance of the bus. In this example, the effective parallel differential termination at the receiver is around 66 Ω. However, the series 93 Ω resistors are always seen by the driver yielding an effective differential impedance of 252 Ω. The receivers see an attenuated signal.

Figure 1. LVPECL System Diagram