EP4CE22F17C6 Datasheet, PDF (10/42 Pages) Altera Corporation – Cyclone IV Device Datasheet

1–10
Chapter 1: Cyclone IV Device Datasheet
Operating Conditions
Example 1–1 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.
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 
Pin Capacitance
Table 1–11 lists the pin capacitance for Cyclone IV devices.
Table 1–11. Pin Capacitance for Cyclone IV Devices ⁽¹⁾
Symbol
Parameter
Typical – Typical – Typical –
Quad Flat Quad Flat Ball-Grid
Pack No Leads Array
Unit
(QFP)
(QFN)
(BGA)
C_IOTB
Input capacitance on top and bottom I/O pins
7
7
C_IOLR
Input capacitance on right I/O pins
7
7
C_LVDSLR Input capacitance on right I/O pins with dedicated LVDS output
8
8
C_VREFLR Input capacitance on right dual-purpose VREF pin when used as
(2)
V_REF or user I/O pin
21
21
C_VREFTB Input capacitance on top and bottom dual-purpose VREF pin when
(2)
used as V_REF or user I/O pin
23 ⁽³⁾
23
C_CLKTB Input capacitance on top and bottom dedicated clock input pins
7
7
C_CLKLR Input capacitance on right dedicated clock input pins
6
6
Notes to Table 1–11:
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 t_CO because of higher pin
capacitance.
(3) C_VREFTB for the EP4CE22 device is 30 pF.
Cyclone IV Device Handbook,
Volume 3
May 2013 Altera Corporation