1–10

Chapter 1: Cyclone III Device Data Sheet

Electrical Characteristics

Cyclone III Device Handbook, Volume 2

© January 2010

Altera Corporation

Internal Weak Pull-Up and Weak Pull-Down Resistor

Table 1–10 lists the weak pull-up and pull-down resistor values for Cyclone III

devices.

Hot Socketing

Table 1–11 lists the hot-socketing specifications for Cyclone III devices.

Schmitt Trigger Input

Cyclone III devices support Schmitt trigger input on 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 signal with

slow edge rate. Table 1–12 lists the hysteresis specifications across supported V

CCIO

range for Schmitt trigger inputs in Cyclone III devices.

Table 1–10. Cyclone III Devices Internal Weak Pull-Up and Weak Pull-Down Resistor

(Note 1)

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

R

_P U

Value of I/O pin pull-up resistor before

and during configuration, as well as

user mode if the programmable

pull-up resistor option is enabled

V

7

2541k

Ω

V

7

2847k

Ω

V

8

3561k

Ω

V

10

57

108

k

Ω

V

13

82

163

k

Ω

V

19

143

351

k

Ω

R

_P D

Value of I/O pin pull-down resistor

before and during configuration

V

6

1930k

Ω

V

6

2236k

Ω

V

6

2543k

Ω

V

7

3571k

Ω

V

850

112

k

Ω

Notes to Table 1–10:

(1) All I/O pins have an option to enable weak pull-up except configuration, test, and JTAG pin. Weak pull-down feature is only available for JTAG

TCK.

Table 1–11. Cyclone III Devices Hot-Socketing Specifications

Symbol

Parameter

Maximum

I

IOPIN(DC )

DC current per I/O pin

300

μA

I

IOPIN(A C)

AC current per I/O pin

8 mA (1)

Note to Table 1–11:

(1) The I/O ramp rate is 10 ns or more. For ramp rates faster than 10 ns, |IIOPIN| = C

dv/dt, in which C is I/O pin capacitance and dv/dt is the slew rate.