AN 447: Interfacing Intel® FPGA Devices with 3.3/3.0/2.5 V LVTTL/LVCMOS I/O Systems

ID 683295
Date 3/28/2022

Guideline: Select Appropriate Driver

The output characteristics of a driver determines how much overshoot voltage is seen at the receiver when the interface is not terminated. You can address signal integrity concerns in your interface by selecting the appropriate driver.

You must select a driver that meets the current limits of the supported Intel® device at the appropriate points in the I/V curve. You can obtain the I/V curve of the driver from the IBIS file provided by the device manufacturer.

You can also use slew rate control, if it is available on the driver, to address signal integrity concerns. Slew rate control allows you to reduce the edge rate of the output signal to help control voltage overshoot at the receiver. You must perform simulations to ensure that the specifications are met when using the slew rate feature.