1–10
Chapter 1: Cyclone IV Device Datasheet
Operating Conditions
December 2016
Altera Corporation
shows how to calculate the change of 50-
I/O impedance from 25°C at
3.0 V to 85°C at 3.15 V.
Pin Capacitance
lists the pin capacitance for Cyclone IV devices.
Example 1–1. Impedance Change
R
V
= (3.15 – 3) × 1000 × –0.026 = –3.83
R
T
= (85 – 25) × 0.262 = 15.72
Because
R
V
is negative,
MF
V
= 1 / (3.83/100 + 1) = 0.963
Because
R
T
is positive,
MF
T
= 15.72/100 + 1 = 1.157
MF = 0.963 × 1.157 = 1.114
R
final
= 50 × 1.114 = 55.71
Table 1–11. Pin Capacitance for Cyclone IV Devices
Symbol
Parameter
Typical –
Quad Flat
Pack
(QFP)
Typical –
Quad Flat
No Leads
(QFN)
Typical –
Ball-Grid
Array
(BGA)
Unit
C
IOTB
Input capacitance on top and bottom I/O pins
7
7
6
pF
C
IOLR
Input capacitance on right I/O pins
7
7
5
pF
C
LVDSLR
Input capacitance on right I/O pins with dedicated LVDS output
8
8
7
pF
C
VREFLR
Input capacitance on right dual
-
purpose
VREF
pin when used as
V
REF
or user I/O pin
21 21 21
pF
C
VREFTB
Input capacitance on top and bottom dual
-
purpose
VREF
pin when
used as V
REF
or user I/O pin
23
23 23
pF
C
CLKTB
Input capacitance on top and bottom dedicated clock input pins
7
7
6
pF
C
CLKLR
Input capacitance on right dedicated clock input pins
6
6
5
pF
Notes to
(1) The pin capacitance applies to FBGA, UBGA, and MBGA packages.
(2) When you use the
VREF
pin as a regular input or output, you can expect a reduced performance of toggle rate and t
CO
because of higher pin
capacitance.
(3) C
VREFTB
for the EP4CE22 device is 30 pF.
Summary of Contents for Cyclone IV
Page 10: ...x Chapter Revision Dates Cyclone IV Device Handbook March 2016 Altera Corporation Volume 1...
Page 14: ...I 2 Section I Device Core Cyclone IV Device Handbook March 2016 Altera Corporation Volume 1...
Page 274: ...vi Contents Cyclone IV Device Handbook February 2015 Altera Corporation Volume 2...
Page 440: ...iv Contents Cyclone IV Device Handbook December 2016 Altera Corporation Volume 3...
Page 442: ...vi Chapter Revision Dates Cyclone IV Device Handbook December 2016 Altera Corporation Volume 3...
Page 446: ......