EP3C5_1 Datasheet, PDF (9/34 Pages) Altera Corporation – Cyclone III Device Data Sheet

Chapter 1: Cyclone III Device Data Sheet
1–9
Electrical Characteristics
Example 1–1 shows you the example to calculate the change of 50 Ω I/O impedance
from 25°C at 3.0 V to 85°C at 3.15 V:
Example 1–1.
ΔR_V = (3.15 – 3) × 1000 × –0.026 = –3.83
ΔR_T = (85 – 25) × 0.262 = 15.72
Because ΔR_V is negative,
MF_V = 1 / (3.83/100 + 1) = 0.963
Because ΔR_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 Ω
Pin Capacitance
Table 1–9 lists the pin capacitance for Cyclone III devices.
Table 1–9. Cyclone III Devices Pin Capacitance
Symbol
Parameter
Typical – Typical –
QFP
FBGA
Unit
CIOTB
Input capacitance on top/bottom I/O pins
7
CIOLR
Input capacitance on left/right I/O pins
7
C_{LV D SL R}
Input capacitance on left/right I/O pins with dedicated
LVDS output
8
6
pF
5
pF
7
pF
C_VREFLR (1)
Input capacitance on left/right dual-purpose VREF pin
when used as V_REF or user I/O pin
21
21
pF
C_VREFTB (1)
Input capacitance on top/bottom dual-purpose VREF pin
when used as V_REF or user I/O pin
23 (2)
23 (2)
pF
C_{C L KT B}
Input capacitance on top/bottom dedicated clock input
pins
7
6
pF
C_{C L KL R}
Input capacitance on left/right dedicated clock input pins
6
5
pF
Notes to Table 1–9:
(1) When VREF pin is used as regular input or output, a reduced performance of toggle rate and tCOis expected due to
higher pin capacitance.
(2) CVREFTB for EP3C25 is 30 pF.
© January 2010 Altera Corporation
Cyclone III Device Handbook, Volume 2