Selectable I/O Standards in Cyclone II Devices
Figure 10–3. SSTL-2 Class I Differential Termination
VTT = 1.25 V
VTT = 1.25 V
Differential
Transmitter
Differential
Receiver
50 Ω
50 Ω
25 Ω
Z
= 50 Ω
0
25 Ω
Z
= 50 Ω
0
Figure 10–4. SSTL-2 Class II Differential Termination
VTT = 1.25 V
VTT = 1.25 V
VTT = 1.25 V
VTT = 1.25 V
Differential
Transmitter
Differential
Receiver
50 Ω
25 Ω
50 Ω
50 Ω
50 Ω
Z
= 50 Ω
0
25 Ω
Z
= 50 Ω
0
1.8-V LVTTL (EIA/JEDEC Standard EIA/JESD8-7)
The 1.8-V I/O standard is used for 1.8-V LVTTL applications. This
standard defines the DC interface parameters for high-speed,
low-voltage, non-terminated digital circuits driving or being driven by
other 1.8-V parts.
The 1.8-V standard does not require input reference voltages or board
terminations. Cyclone II devices support input and output levels for
1.8-V LVTTL.
Altera Corporation
February 2008
10–9
Cyclone II Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
