Hot Socketing
I/O Pins Remain Tri-Stated during Power-Up
A device that does not support hot-socketing may interrupt system
operation or cause contention by driving out before or during power-up.
In a hot socketing situation, the MAX II device’s output buffers are turned
off during system power-up. MAX II devices do not drive out until the
device attains proper operating conditions and is fully configured. See
“Power-On Reset Circuitry” on page 4–6 for information about turn-on
voltages.
Signal Pins Do Not Drive the VCCIO or VCCINT Power Supplies
MAX II devices do not have a current path from I/O pins or GCLK[3..0]
pins to the VCCIO or VCCINT pins before or during power-up. A MAX II
device may be inserted into (or removed from) a system board that was
powered up without damaging or interfering with system-board
operation. When hot socketing, MAX II devices may have a minimal
effect on the signal integrity of the backplane.
AC & DC Specifications
You can power up or power down the VCCIO and VCCINT pins in any
sequence. During hot socketing, the I/O pin capacitance is less than 8 pF.
MAX II devices meet the following hot socketing specifications:
■
■
The hot socketing DC specification is: | IIOPIN | < 300 μA.
The hot socketing AC specification is: | IIOPIN | < 8 mA for 10 ns or
less.
1
MAX II devices are immune to latch-up when hot socketing. If
the TCKJTAG input pin is driven high during hot-socketing, the
current on that pin might exceed the specifications above.
IIOPIN is the current at any user I/O pin on the device. The AC
specification applies when the device is being powered up or powered
down. This specification takes into account the pin capacitance but not
board trace and external loading capacitance. Additional capacitance for
trace, connector, and loading must be taken into consideration separately.
The peak current duration due to power-up transients is 10 ns or less.
The DC specification applies when all VCC supplies to the device are
stable in the powered-up or powered-down conditions.
4–2
Core Version a.b.c variable
Altera Corporation
February 2006
MAX II Device Handbook, Volume 1
INTEL [ INTEL ]
