Uncalibrated Source Termination in HP I/O banks

UltraScale Architecture SelectIO Resources User Guide (UG571)

Document ID
UG571
Release Date
2022-08-31
Revision
1.14 English

HP I/O banks have an optional uncalibrated source termination feature for SSTL, HSTL, POD, and HSUL standards that is similar to DCI. This feature provides an option of 40W, 48W, or a 60W driver for the supported standards to match the characteristic impedance of the driven line.

An important difference between this uncalibrated option and DCI is that instead of calibrating to an external reference resistor on the VRP pin when using DCI, the uncalibrated source termination feature invokes internal resistors determined by the OUTPUT_IMPEDANCE attribute where no calibration routine is available to compensate for temperature, process, or voltage variations.

 

IMPORTANT:   This feature is only available in HP I/O banks.

The allowed values for OUTPUT_IMPEDANCE are RDRV_40_40, RDRV_48_48, or RDRV_60_60.

The main difference in how DCI or uncalibrated termination is invoked in a design is determined when choosing to use either a DCI I/O standard or an uncalibrated one. In both DCI and uncalibrated I/O standards, source termination value is determined by the attribute OUTPUT_IMPEDANCE.

Table: I/O Standards that Support Uncalibrated Source Termination in HP I/O Banks  shows a list of I/O standards that support uncalibrated source termination in HP I/O banks.

Table 1-8:      I/O Standards that Support Uncalibrated Source Termination in HP I/O Banks 

HSTL_I

DIFF_HSTL_I

SSTL18_I

DIFF_SSTL18_I

POD12

DIFF_POD12

HSTL_I_18

DIFF_HSTL_I_18

SSTL15

DIFF_SSTL15

POD10

DIFF_POD10

HSTL_I_12

DIFF_HSTL_I_12

SSTL135

DIFF_SSTL135

HSUL_12

DIFF_HSUL_12

 

 

SSTL12

DIFF_SSTL12