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EP4CE6E22C8N Datasheet, PDF (10/42 Pages) Altera Corporation – Cyclone IV Device Datasheet | |||
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1â10
Chapter 1: Cyclone IV Device Datasheet
Operating Conditions
Example 1â1 shows how to calculate the change of 50-ïï I/O impedance from 25°C at
3.0 V to 85°C at 3.15 V.
Example 1â1. Impedance Change
ïRV = (3.15 â 3) Ã 1000 Ã â0.026 = â3.83
ïRT = (85 â 25) Ã 0.262 = 15.72
Because ïRV is negative,
MFV = 1 / (3.83/100 + 1) = 0.963
Because ïRT is positive,
MFT = 15.72/100 + 1 = 1.157
MF = 0.963 Ã 1.157 = 1.114
Rfinal = 50 Ã 1.114 = 55.71 ï
Pin Capacitance
Table 1â11 lists the pin capacitance for Cyclone IV devices.
Table 1â11. Pin Capacitance for Cyclone IV Devices (1)
Symbol
Parameter
Typical â Typical â Typical â
Quad Flat Quad Flat Ball-Grid
Pack No Leads Array
Unit
(QFP)
(QFN)
(BGA)
CIOTB
Input capacitance on top and bottom I/O pins
7
7
CIOLR
Input capacitance on right I/O pins
7
7
CLVDSLR Input capacitance on right I/O pins with dedicated LVDS output
8
8
CVREFLR Input capacitance on right dual-purpose VREF pin when used as
(2)
VREF or user I/O pin
21
21
CVREFTB Input capacitance on top and bottom dual-purpose VREF pin when
(2)
used as VREF or user I/O pin
23 (3)
23
CCLKTB Input capacitance on top and bottom dedicated clock input pins
7
7
CCLKLR Input capacitance on right dedicated clock input pins
6
6
Notes to Table 1â11:
6
pF
5
pF
7
pF
21
pF
23
pF
6
pF
5
pF
(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 tCO because of higher pin
capacitance.
(3) CVREFTB for the EP4CE22 device is 30 pF.
Cyclone IV Device Handbook,
Volume 3
May 2013 Altera Corporation
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