MAX® 10 FPGA Design Guidelines

ID 683196
Date 5/15/2024
Document Table of Contents Verify I/O termination and impedance matching

Voltage-referenced I/O standards require both a VREF and a termination voltage (VTT). The reference voltage of the receiving device tracks the termination voltage of the transmitting device. Consider the following items:
  • Each voltage-referenced I/O standard requires a unique termination setup. For example, a proper resistive signal termination scheme is critical in SSTL-2 standards to produce a reliable DDR memory system with superior noise margin.
  • Although single-ended, non-voltage-referenced I/O standards do not require termination, impedance matching is necessary to reduce reflections and improve signal integrity.
  • Differential I/O standards typically require a termination resistor between the two signals at the receiver. The termination resistor must match the differential load impedance of the signal line.

    The MAX® 10 on-chip series termination provides the convenience of no external components. You can also use external pull-up resistors to terminate the voltage-referenced I/O standards such as SSTL and HSTL.