Altera Cyclone IV - Voltage-Referenced I;O Standard Termination

6–14 Chapter 6: I/O Features in Cyclone IV Devices
Termination Scheme for I/O Standards
Cyclone IV Device Handbook, March 2016 Altera Corporation
Volume 1
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 Figure 6–5 and Figure 6–6.
Figure 6–5. Cyclone IV Devices HSTL I/O Standard Termination
HSTL Class I
HSTL Class II
External
On-Board
Termination
OCT with
and without
Calibration
V
TT
50 Ω
50 Ω
V
TT
50 Ω
V
TT
50 Ω
Transmitter TransmitterReceiver Receiver
V
TT
50 Ω
Transmitter Receiver
V
TT
50 Ω
V
TT
50 Ω
Transmitter Receiver
Cyclone IV Device
Family Series OCT
50 Ω
Cyclone IV Device
Family Series OCT
25
Ω
V
REF
V
REF
V
REF
V
REF
Termination
50 Ω
50 Ω
50 Ω
Figure 6–6. Cyclone IV Devices SSTL I/O Standard Termination
SSTL Class I SSTL Class II
External
On-Board
Termination
OCT with
and without
Calibration
V
TT
50 Ω
25 Ω
V
TT
50 Ω
25 Ω
V
TT
50 Ω
Transmitter TransmitterReceiver Receiver
V
TT
50 Ω
50 Ω
Transmitter Receiver
Cyclone IV Device
Family Series OCT
50 Ω
V
TT
50 Ω
25 Ω
50 Ω
V
TT
50 Ω
Transmitter Receiver
Cyclone IV Device
Family Series OCT
V
REF
V
REF
V
REF
V
REF
Termination
50 Ω
50 Ω