4. Hot Socketing &
Power-On Reset
SII51004-3.2
Stratix® II devices offer hot socketing, which is also known as hot plug-in
or hot swap, and power sequencing support without the use of any
external devices. You can insert or remove a Stratix II board in a system
during system operation without causing undesirable effects to the
running system bus or the board that was inserted into the system.
The hot socketing feature also removes some of the difficulty when you
use Stratix II devices on printed circuit boards (PCBs) that also contain a
mixture of 5.0-, 3.3-, 2.5-, 1.8-, 1.5- and 1.2-V devices. With the Stratix II hot
socketing feature, you no longer need to ensure a proper power-up
sequence for each device on the board.
The Stratix II hot socketing feature provides:
■
Board or device insertion and removal without external components
or board manipulation
■
■
Support for any power-up sequence
Non-intrusive I/O buffers to system buses during hot insertion
This chapter also discusses the power-on reset (POR) circuitry in Stratix II
devices. The POR circuitry keeps the devices in the reset state until the
VCC is within operating range.
Stratix II devices offer hot socketing capability with all three features
listed above without any external components or special design
requirements. The hot socketing feature in Stratix II devices allows:
Stratix II
Hot-Socketing
Specifications
■
■
The device can be driven before power-up without any damage to
the device itself.
I/O pins remain tri-stated during power-up. The device does not
drive out before or during power-up, thereby affecting other buses in
operation.
■
Signal pins do not drive the VCCIO, VCCPD, or VCCINT power supplies.
External input signals to I/O pins of the device do not internally
power the VCCIO or VCCINT power supplies of the device via internal
paths within the device.
Altera Corporation
May 2007
4–1
ALTERA [ ALTERA CORPORATION ]
