6–14
Chapter 6: I/O Features in the Cyclone III Device Family
Termination Scheme for I/O Standards
Voltage-Referenced I/O Standard Termination
Voltage-referenced I/O standards require an input reference voltage (V
REF
) and a
termination voltage (V
TT
). The reference voltage of the receiving device tracks the
termination voltage of the transmitting device, as shown in
and
Figure 6–6. Cyclone III Device Family HSTL I/O Standard Termination
Termination
HSTL Class I
HSTL Class II
VTT
VTT
50
VTT
50
External
On-Board
Termination
Transmitter
50
50
VREF
Receiver
Transmitter
50
VREF
Receiver
OCT with
and without
Calibration
Cyclone III Device
Family Series OCT
50
VTT
50
50
VREF
Cyclone III Device
Family Series OCT
25
VTT
50
VTT
50
50
VREF
Receiver
Transmitter
Receiver
Transmitter
Figure 6–7. Cyclone III Device Family SSTL I/O Standard Termination
Termination
SSTL Class I
SSTL Class II
VTT
VTT
50
25
VTT
50
50
VREF
External
On-Board
Termination
25
50
50
VREF
Transmitter
Receiver
Transmitter
Receiver
Cyclone III Device
Family Series OCT
50
VTT
50
50
Cyclone III Device
Family Series OCT
25
VTT
50
VTT
50
50
OCT with
and without
Calibration
VREF
VREF
Transmitter
Receiver
Transmitter
Receiver
Cyclone III Device Handbook
Volume 1
July 2012 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
