4–2
Chapter 4: Hot Socketing and Power-On Reset in MAX V Devices
MAX V Hot-Socketing Specifications
Devices Can Be Driven Before Power Up
You can drive signals into the I/O pins and GCLK[3..0]pins of MAX V devices before
or during power up or power down without damaging the device. To simplify the
system-level design, MAX V devices support any power-up or power-down sequence
(VCCIO1, VCCIO2, VCCIO3, VCCIO4, and VCCINT).
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 V device’s output buffers are turned off during system power up. MAX V
devices do not drive out until the device attains proper operating conditions and is
fully configured. For more information about turn-on voltages, refer to “Power-On
Reset Circuitry” on page 4–5.
Signal Pins Do Not Drive the VCCIO or VCCINT Power Supplies
MAX V devices do not have a current path from the I/O pins or GCLK[3..0]pins to
the VCCIO or VCCINT power supplies before or during power up. A MAX V device may
be inserted into (or removed from) a system board that is powered up without
damaging or interfering with system-board operation. When hot socketing, MAX V
devices may have a minimal effect on the signal integrity of the backplane.
AC and DC Specifications
You can power up or power down the VCCIO and VCCINT power supplies in any
sequence. During hot socketing, the I/O pin capacitance is less than 8 pF. MAX V
devices meet the following hot-socketing specifications:
■
■
DC specification: | IIOPIN | < 300 A.
AC specification: | IIOPIN | < 8 mA for 10 ns or less.
1
MAX V 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 listed above.
IIOPIN is the current for 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 the board trace and external loading capacitance.
You must consider additional capacitance for trace, connector, and loading 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.
MAX V Device Handbook
December 2010 Altera Corporation
ALTERA [ ALTERA CORPORATION ]
