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Altera Corporation
January 2007
4–7
Preliminary
Operating Conditions
Table 4–16. Cyclone Device Capacitance
Note (14)
Symbol
Parameter
Typical
Unit
C
IO
Input capacitance for user I/O pin
4.0
pF
C
LVDS
Input capacitance for dual-purpose LVDS/user I/O pin
4.7
pF
C
VREF
Input capacitance for dual-purpose V
REF
/user I/O pin.
12.0
pF
C
DPCLK
Input capacitance for dual-purpose
DPCLK
/user I/O pin.
4.4
pF
C
CLK
Input capacitance for CLK pin.
4.7
pF
Notes to
Tables 4–1
through
4–16
:
(1)
Refer to the
Operating Requirements for Altera Devices Data Sheet
.
(2)
Conditions beyond those listed in
Table 4–1
may cause permanent damage to a device. Additionally, device
operation at the absolute maximum ratings for extended periods of time may have adverse affects on the device.
(3)
Minimum DC input is –0.5 V. During transitions, the inputs may undershoot to –2.0 V or overshoot to 4.6 V for
input currents less than 100 mA and periods shorter than 20 ns.
(4)
Maximum V
CC
rise time is 100 ms, and V
CC
must rise monotonically.
(5)
All pins, including dedicated inputs, clock, I/O, and JTAG pins, may be driven before V
CCINT
and V
CCIO
are
powered.
(6)
Typical values are for T
A
= 25
°
C, V
CCINT
= 1.5 V, and V
CCIO
= 1.5 V, 1.8 V, 2.5 V, and 3.3 V.
(7)
V
I
= ground, no load, no toggling inputs.
(8)
This value is specified for normal device operation. The value may vary during power-up. This applies for all
V
CCIO
settings (3.3, 2.5, 1.8, and 1.5 V).
(9)
R
CONF
is the measured value of internal pull-up resistance when the I/O pin is tied directly to GND. R
CONF
value
will be lower if an external source drives the pin higher than V
CCIO
.
(10) Pin pull-up resistance values will lower if an external source drives the pin higher than V
CCIO
.
(11) Drive strength is programmable according to values in
Chapter 2, Cyclone Architecture
,
Table 2–11
.
(12) Overdrive is possible when a 1.5 V or 1.8 V and a 2.5 V or 3.3 V input signal feeds an input pin. Turn on “Allow
voltage overdrive” for LVTTL/LVCMOS input pins in the Assignments > Device > Device and Pin Options > Pin
Placement tab when a device has this I/O combination. However, higher leakage current is expected.
(13) The Cyclone LVDS interface requires a resistor network outside of the transmitter channels.
(14) Capacitance is sample-tested only. Capacitance is measured using time-domain reflections (TDR). Measurement
accuracy is within
±
0.5 pF.