EP3C5E144C8N Datasheet, PDF (113/348 Pages) Altera Corporation – Ability to disable external JTAG port

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
December 2011 Altera Corporation
Cyclone III Device Handbook
Volume 1