Power-Up/-Down Behavior of ProASIC3/E Devices
v1.3
20- 7
Cold-Sparing
In cold-sparing applications, voltage can be applied to device I/Os before and during power-up.
Cold-sparing applications rely on three important characteristics of the device:
1. I/Os must be tristated before and during power-up.
2. Voltage applied to the I/Os must not power up any part of the device.
3. Device reliability must not be compromised if voltage is applied to I/Os before or during
power-up.
tristated before and during power-up until the last voltage supply (VCC or VCCI) is powered up past
its functional level. Furthermore, applying voltage to the ProASIC3/E I/Os does not pull up VCC or
VCCI and, therefore, does not partially power up the device. Table 20-1 includes the cold-sparing test results on A3PE600-PQ208 EAS devices. In this test, leakage current on the device I/O and
residual voltage on the power supply rails were measured while voltage was applied to the I/O
before power-up.
The reliability of ProASIC3/E I/Os is guaranteed if the voltage level, applied to the device I/Os, is less
than 3.6 V, as specified in the product datasheets. Therefore, ProASIC3/E devices meet all three
requirements stated earlier in this section and are suitable for cold-sparing applications.
Hot-Swap
Hot-swapping is the operation of hot insertion or hot removal of a card in a powered-up system.
The I/Os need to be configured in hot-insertion mode if hot-swapping compliance is required. All
ProASIC3E devices support hot-swapping, and the only ProASIC3 device supporting hot-swapping is
the A3P030. For more details on the levels of hot-swap compatibility in ProASIC3/E devices, refer to
the "Hot-Swap Support" section in the I/O Structures chapter of the handbook for the device you
are using.
Conclusion
Actel's ProASIC3/E flash FPGAs provide an excellent programmable logic solution for a broad range
of applications. In addition to high performance, low cost, security, nonvolatility, and single chip,
they are live at power-up (meet Level 0 of the LAPU classification) and offer clear and easy-to-use
power-up/-down characteristics. Unlike SRAM FPGAs, ProASIC3/E devices do not require any specific
power-up/-down sequencing and have extremely low power-up inrush current in any power-up
sequence. ProASIC3/E FPGAs also support both cold-sparing and hot-swapping for applications
requiring these capabilities.
Table 20-1 Cold-Sparing Test Results for A3PE600 Devices
Device I/O
Residual Voltage (V)
Leakage Current
VCC
VCCI
Input
0
0.003
<1 A
Output
0
0.003
<1 A