4. Hot Socketing and Power-On Reset in
MAX V Devices
December 2010
MV51004-1.0
MV51004-1.0
This chapter provides information about hot-socketing specifications, power-on reset
(POR) requirements, and their implementation in MAX V devices.
MAX V devices offer hot socketing, also known as hot plug-in or hot swap, and
power sequencing support. You can insert or remove a MAX V device in a system
during system operation without causing undesirable effects to the running system
bus. The hot-socketing feature removes some of the difficulty when using MAX V
devices on PCBs that contain a mixture of 3.3-, 2.5-, 1.8-, and 1.5-V devices.
The MAX V hot-socketing feature provides the following:
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Board or device insertion and removal
Support for any power-up sequence
Non-intrusive I/O buffers to system buses during hot insertion
This chapter contains the following sections:
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■
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“MAX V Hot-Socketing Specifications” on page 4–1
“Hot-Socketing Feature Implementation in MAX V Devices” on page 4–3
“Power-On Reset Circuitry” on page 4–5
MAX V Hot-Socketing Specifications
MAX V devices offer the hot-socketing feature without the need for external
components or special design requirements. The advantages of hot-socketing support
in MAX V devices includes the following:
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■
■
The device can be driven before and during power up or power down without
damaging the device.
I/O pins remain tri-stated during power up. The device does not drive out before
or during power up, thereby affecting other operating buses.
Signal pins do not drive the VCCIO or VCCINT power supplies. External input signals
to the device I/O pins do not power the device VCCIO or VCCINT power supplies
using internal paths. This is true if the VCCINT and VCCIO power supplies are held at
GND.
1
Altera uses GND as a reference for the hot-socketing and I/O buffers circuitry
designs. To ensure device reliability and compliance to the hot-socketing
specifications, you must connect GND between boards before connecting the VCCINT
and VCCIO power supplies.
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MAX V Device Handbook
December 2010
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