EP3C10U256C6N Datasheet, PDF (113/274 Pages) Altera Corporation – Cyclone III Device Family Overview

Chapter 6: I/O Features in the Cyclone III Device Family
Termination Scheme for I/O Standards
6–15
Differential I/O Standard Termination
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 bus (Figure 6–8 and Figure 6–9).
The Cyclone III device family supports differential SSTL-2 and SSTL-18, differential
HSTL-18, HSTL-15, and HSTL-12, PPDS, LVDS, RSDS, mini-LVDS, and
differential LVPECL.
Figure 6–8. Cyclone III Device Family Differential HSTL I/O Standard Termination
Termination
Differential HSTL
VTT VTT
External
On-Board
Termination
Transmitter
OCT
Cyclone III Device
Family Series OCT
50 
Transmitter
VTT VTT
Receiver
Receiver
Figure 6–9. Cyclone III Device Family Differential SSTL I/O Standard Termination ⁽¹⁾
Termination
Differential SSTL Class I
External
On-Board
Termination
VTT VTT
50 
25 
50 
50 
25 
50
Transmitter
OCT
Cyclone III Device
Family Series OCT
50 
Receiver
VTT VTT
50  50 
50 
Transmitter
50 
Receiver
Note to Figure 6–9:
(1) Only Differential SSTL-2 I/O standard supports Class II output.
Differential SSTL Class II
VTT VTT
VTT VTT
50 
25 
50  50 
50 
50 
25 
50 
Transmitter
VTT VTT
VTT VTT
Cyclone III Device
Family Series OCT
25 
50  50  50 50 
50 
Receiver
Transmitter
50 
Receiver
July 2012 Altera Corporation
Cyclone III Device Handbook
Volume 1