EP4CE30F29C7N Datasheet, PDF (120/488 Pages) Altera Corporation – Cyclone IV Device Handbook, Volume 1

6–14
Chapter 6: I/O Features in Cyclone IV Devices
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 Figure 6–5 and Figure 6–6.
Figure 6–5. Cyclone IV Devices HSTL I/O Standard Termination
Termination
HSTL Class I
HSTL Class II
External
On-Board
Termination
Transmitter
VTT
50 Ω
50 Ω
VREF
Receiver
Transmitter
VTT
VTT
50 Ω 50 Ω
50 Ω
VREF
Receiver
OCT with
and without
Calibration
Cyclone IV Device
Family Series OCT
50 Ω
Transmitter
VTT
50 Ω
50 Ω
VREF
Receiver
Cyclone IV Device
Family Series OCT
25 Ω
VTT
50 Ω
VTT
50 Ω
50 Ω
VREF
Transmitter
Receiver
Figure 6–6. Cyclone IV Devices SSTL I/O Standard Termination
Termination
SSTL Class I
SSTL Class II
External
On-Board
Termination
VTT
25 Ω
50 Ω
50 Ω
VREF
Transmitter
Receiver
OCT with
and without
Calibration
Cyclone IV Device
Family Series OCT
50 Ω
VTT
50 Ω
50 Ω
VREF
Transmitter
Receiver
VTT
VTT
50 Ω
25 Ω
50 Ω
50 Ω
VREF
Transmitter
Receiver
Cyclone IV Device
Family Series OCT
25 Ω
VTT
50 Ω
VTT
50 Ω
50 Ω
VREF
Transmitter
Receiver
Cyclone IV Device Handbook,
Volume 1
May 2013 Altera Corporation