A54SX08A-FTQ144 Datasheet, PDF (12/108 Pages) Actel Corporation – SX-A Family FPGAs

SX-A Family FPGAs
Power-Up/Down and Hot Swapping
SX-A I/Os are configured to be hot-swappable, with the
exception of 3.3 V PCI. During power-up/down (or partial
up/down), all I/Os are tristated. V_CCA and V_CCI do not
have to be stable during power-up/down, and can be
powered up/down in any order. When the SX-A device is
plugged into an electrically active system, the device will
not degrade the reliability of or cause damage to the
host system. The device’s output pins are driven to a high
impedance state until normal chip operating conditions
are reached. Table 1-4 summarizes the V_CCA voltage at
which the I/Os behave according to the user’s design for
an SX-A device at room temperature for various ramp-up
rates. The data reported assumes a linear ramp-up
profile to 2.5 V. For more information on power-up and
hot-swapping, refer to the application note, Actel SX-A
and RT54SX-S Devices in Hot-Swap and Cold-Sparing
Applications.
Table 1-2 • I/O Features
Function
Description
Input Buffer Threshold Selections
• 5 V: PCI, TTL
• 3.3 V: PCI, LVTTL
• 2.5 V: LVCMOS2 (commercial only)
Flexible Output Driver
• 5 V: PCI, TTL
• 3.3 V: PCI, LVTTL
• 2.5 V: LVCMOS2 (commercial only)
Output Buffer
“Hot-Swap” Capability (3.3 V PCI is not hot swappable)
• I/O on an unpowered device does not sink current
• Can be used for “cold-sparing”
Selectable on an individual I/O basis
Individually selectable slew rate; high slew or low slew (The default is high slew rate).
The slew is only affected on the falling edge of an output. Rising edges of outputs are
not affected.
Power-Up
Individually selectable pull-ups and pull-downs during power-up (default is to power-up
in tristate)
Enables deterministic power-up of device
V_CCA and V_CCI can be powered in any order
Table 1-3 • I/O Characteristics for All I/O Configurations
Hot Swappable
Slew Rate Control
Power-Up Resistor
TTL, LVTTL, LVCMOS2
Yes
Yes. Only affects falling edges of outputs Pull-up or pull-down
3.3 V PCI
No
No. High slew rate only
Pull-up or pull-down
5 V PCI
Yes
No. High slew rate only
Pull-up or pull-down
Table 1-4 • Power-Up Time at which I/Os Become Active
Supply Ramp Rate 0.25 V/μs 0.025 V/μs 5 V/ms
Units
μs
μs
ms
A54SX08A
10
96
0.34
A54SX16A
10
100
0.36
A54SX32A
10
100
0.46
A54SX72A
10
100
0.41
2.5 V/ms
ms
0.65
0.62
0.74
0.67
0.5 V/ms
ms
2.7
2.5
2.8
2.6
0.25 V/ms
ms
5.4
4.7
5.2
5.0
0.1 V/ms
ms
12.9
11.0
12.1
12.1
0.025 V/ms
ms
50.8
41.6
47.2
47.2
1-8
v5.3