Stratix® 10 General Purpose I/O User Guide

ID 683518
Date 10/07/2024
Public
Document Table of Contents

2.4.2. RS OCT with Calibration in Stratix® 10 Devices

The Stratix® 10 devices support RS OCT with calibration in all LVDS I/O banks.

Table 11.  Selectable I/O Standards for RS OCT With CalibrationThis table lists the output termination settings for calibrated OCT on different I/O standards.
I/O Standard Calibrated OCT (Output)
RS (Ω) RZQ (Ω)
1.8 V LVCMOS 25, 50 100
1.5 V LVCMOS 25, 50 100
1.2 V LVCMOS 25, 50 100
SSTL-18 Class I 50 100
SSTL-18 Class II 25 100
SSTL-15 Class I 50 100
SSTL-15 Class II 25 100
SSTL-15 34, 40 240
SSTL-135 34, 40 240
SSTL-125 34, 40 240
SSTL-12 34, 40, 60, 120, 240 240
POD12 34, 40, 48, 60 240
1.8 V HSTL Class I 50 100
1.8 V HSTL Class II 25 100
1.5 V HSTL Class I 50 100
1.5 V HSTL Class II 25 100
1.2 V HSTL Class I 50 100
1.2 V HSTL Class II 25 100
HSUL-12 34, 40, 48, 60, 80 240
Differential SSTL-18 Class I 50 100
Differential SSTL-18 Class II 25 100
Differential SSTL-15 Class I 50 100
Differential SSTL-15 Class II 25 100
Differential SSTL-15 34, 40 240
Differential SSTL-135 34, 40 240
Differential SSTL-15 Class I 50 100
Differential SSTL-15 Class II 25 100
Differential SSTL-125 34, 40 240
Differential SSTL-12 34, 40, 60, 120, 240 240
Differential POD12 34, 40, 48, 60 240
Differential 1.8 V HSTL Class I 50 100
Differential 1.8 V HSTL Class II 25 100
Differential 1.5 V HSTL Class I 50 100
Differential 1.5 V HSTL Class II 25 100
Differential 1.2 V HSTL Class I 50 100
Differential 1.2 V HSTL Class II 25 100
Differential HSUL-12 34, 40, 48, 60, 80 240

The RS OCT calibration circuit compares the total impedance of the I/O buffer to the external reference resistor connected to the RZQ pin and dynamically enables or disables the transistors until they match.

Calibration occurs at the end of device configuration. When the calibration circuit finds the correct impedance, the circuit powers down and stops changing the characteristics of the drivers.

Figure 11. RS OCT with CalibrationThis figure shows the RS as the intrinsic impedance of the output transistors.