EP4SE360F35I4 Datasheet, PDF (202/432 Pages) Altera Corporation – This section provides a complete overview of all features relating to the Stratix IV device family, which is the most architecturlly advanced

6–28
Chapter 6: I/O Features in Stratix IV Devices
On-Chip Termination Support and I/O Termination Schemes
On-Chip Parallel Termination with Calibration
Stratix IV devices support on-chip parallel termination with calibration in all banks.
On-chip parallel termination with calibration is only supported for input
configuration of input and bidirectional pins. Output pin configurations do not
support on-chip parallel termination with calibration. Figure 6–20 shows on-chip
parallel termination with calibration. When you use parallel OCT, the V_CCIO of the
bank must match the I/O standard of the pin where the parallel OCT is enabled.
Figure 6–20. On-Chip Parallel Termination with Calibration
Stratix IV OCT
V_CCIO
Z_O = 50 Ω
V_REF
100 Ω
100 Ω
Transmitter
GND Receiver
The on-chip parallel termination calibration circuit compares the total impedance of
the I/O buffer to the external 50- ±1% resistors connected to the RUP and RDN pins
and dynamically enables or disables the transistors until they match. Calibration
occurs at the end of device configuration. When the calibration circuit finds the
correct impedance, it powers down and stops changing the characteristics of the
drivers. Table 6–7 lists the I/O standards that support on-chip parallel termination
with calibration.
Table 6–7. Selectable I/O Standards with On-Chip Parallel Termination with Calibration
I/O Standard
SSTL-2 Class I, II
SSTL-18 Class I, II
SSTL-15 Class I, II
HSTL-18 Class I, II
HSTL-15 Class I, II
HSTL-12 Class I, II
Differential SSTL-2 Class I, II
Differential SSTL-18 Class I, II
Differential SSTL-15 Class I, II
Differential HSTL-18 Class I, II
Differential HSTL-15 Class I, II
Differential HSTL-12 Class I, II
On-Chip Parallel
Termination Setting
(Column I/O) ()
50
50
50
50
50
50
50
50
50
50
50
50
On-Chip Parallel
Termination Setting
(Row I/O) ()
50
50
50
50
50
50
50
50
50
50
50
50
Stratix IV Device Handbook
Volume 1
September 2012 Altera Corporation