Schmitt Trigger Input; I/O Standard Specifications - Altera Cyclone IV Device Handbook

1–12

Schmitt Trigger Input

Cyclone IV devices support Schmitt trigger input on the TDI, TMS, TCK, nSTATUS,
nCONFIG, nCE, CONF_DONE, and DCLK pins. A Schmitt trigger feature introduces
hysteresis to the input signal for improved noise immunity, especially for signals with
slow edge rate.
V
CCIO
Table 1–14. Hysteresis Specifications for Schmitt Trigger Input in Cyclone IV Devices
V
SCHMITT

I/O Standard Specifications

The following tables list input voltage sensitivities (V
and V
supported by Cyclone IV devices.
standard specifications for Cyclone IV devices.
Table 1–15. Single - Ended I/O Standard Specifications for Cyclone IV Devices
I/O Standard
Min
(3)
- V LVTTL
3.3 3.135
- V LVCMOS (3)
3.3 3.135
(3)
3.0 - V LVTTL 2.85
(3)
3.0 - V LVCMOS 2.85
(3)
2.5 V 2.375
1.8 V 1.71
1.5 V 1.425
1.2 V 1.14
3.0-V PCI 2.85
3.0-V PCI-X 2.85
Notes to Table 1–15:
-
(1) For voltage referenced receiver input waveform and explanation of terms used in
(2) AC load CL = 10 pF
(3) For more information about interfacing Cyclone IV devices with 3.3/3.0/2.5
and Cyclone IV Devices with 3.3/3.0/2.5-V LVTTL/LVCMOS I/O
(4) To meet the I and I specifications, you must set the current strength settings accordingly. For example, to meet the 3.3-V LVTTL specification (4
OL OH
mA), set the current strength settings to 4 mA or higher. Setting at lower current strength may not meet the I
Cyclone IV Device Handbook,
Volume 3
Table 1–14 lists the hysteresis specifications across the supported
range for Schmitt trigger inputs in Cyclone IV devices.
Symbol Parameter
Hysteresis for Schmitt trigger
input
), and current drive characteristics (I
OL
V (V) V (V)
CCIO IL
Typ Max Min Max
3.3 3.465 — 0.8
3.3 3.465 — 0.8
3.0 3.15 –0.3 0.8
3.0 3.15 –0.3 0.8
2.5 2.625 –0.3 0.7
0.35 x
1.8 1.89 –0.3
V
0.35 x
1.5 1.575 –0.3
V
0.35 x
1.2 1.26 –0.3
V
0.3 x
3.0 3.15 —
V
0.35 x
3.0 3.15 —
V
Conditions (V)
V = 3.3
CCIO
V = 2.5
CCIO
V = 1.8
CCIO
V = 1.5
CCIO
and I
OH
Table 1–15 through
(1), (2)
V (V)
IH
Min Max
1.7 3.6
1.7 3.6
1.7 V + 0.3
CCIO
1.7 V + 0.3
CCIO
1.7 V + 0.3
CCIO
0.65 x
2.25
V
CCIO CCIO
0.65 x
V + 0.3
CCIO
V
CCIO CCIO
0.65 x
V + 0.3
CCIO
V
CCIO CCIO
0.5 x
V + 0.3 0.1 x V
CCIO
V
CCIO CCIO
0.5 x
V + 0.3 0.1 x V
CCIO
V
CCIO CCIO
Table 1–15, refer to
-
V LVTTL/LVCMOS I/O standards, refer to
Systems.
Chapter 1: Cyclone IV Device Datasheet
Operating Conditions
Minimum
200
200
140
110
and V ), output voltage (V
IH IL
), for various I/O standards
OL
Table 1–20 provide the I/O
V (V) V (V)
OL OH
(mA)
Max Min
0.45 2.4
0.2 V – 0.2
CCIO
0.45 2.4
0.2 V – 0.2
CCIO
0.4 2.0
V –
CCIO
0.45
0.45
0.25 x 0.75 x
V V
CCIO CCIO
0.25 x 0.75 x
V V
CCIO CCIO
0.9 x V
CCIO CCIO
0.9 x V
CCIO CCIO
"Glossary" on page 1–37.
AN 447: Interfacing Cyclone III
and I specifications in the handbook.
OL OH
December 2016 Altera Corporation
Unit
mV
mV
mV
mV
OH
I I
OL OH
(mA)
(4) (4)
4 –4
2 –2
4 –4
0.1 –0.1
1 –1
2 –2
2 –2
2 –2
1.5 –0.5
1.5 –0.5