a3p250l Actel Corporation, a3p250l Datasheet - Page 15

• Manufacturer Part Number: a3p250l
• Description: Proasic3l Low-power Flash Fpgas With Flash*freeze Technology
• Manufacturer: Actel Corporation

Table 2-4 •
I/O Power-Up and Supply Voltage Thresholds for Power-On Reset
(Commercial and Industrial)
Sophisticated power-up management circuitry is designed into every ProASIC
circuits ensure easy transition from the powered-off state to the powered-up state of the device.
The many different supplies can power up in any sequence with minimized current spikes or surges.
In addition, the I/O will be in a known state through the power-up sequence. The basic principle is
shown in
There are five regions to consider during power-up.
ProASIC3 I/Os are activated only if ALL of the following three conditions are met:
V
Ramping up: 0.6 V < trip_point_up < 1.2 V
Ramping down: 0.5 V < trip_point_down < 1.1 V
V
Ramping up: 0.6 V < trip_point_up < 1.1 V
Ramping down: 0.5 V < trip_point_down < 1 V
V
specifically built-in hysteresis prevents undesirable power-up oscillations and current surges. Note
the following:
V
2.7 V or less
3 V
3.3 V
3.6 V
Notes:
1. Based on reliability requirements at junction temperature at 85°C.
2. The duration is allowed at one out of six clock cycles. If the overshoot/undershoot occurs at
3. This table does not provide PCI overshoot/undershoot limits.
CC
CCI
CC
CCI
1. V
2. V
3. Chip is in the operating mode.
•
•
one out of two cycles, the maximum overshoot/undershoot has to be reduced by 0.15 V.
Trip Point:
and V
Trip Point:
Figure 2-2 on page
During programming, I/Os become tristated and weakly pulled up to V
JTAG supply, PLL power supplies, and charge pump V
behavior.
CC
CCI
Figure 2-1 on page 2-4
CCI
and V
> V
Overshoot and Undershoot Limits
ramp-up trip points are about 100 mV higher than ramp-down trip points. This
CC
– 0.75 V (typical)
CCI
are above the minimum specified trip points
Average V
Duration as a Percentage of Clock Cycle
2-5).
CCI
and
–GND Overshoot or Undershoot
A dv a n c e v 0. 4
Figure 2-2 on page
10%
10%
10%
10%
5%
5%
5%
5%
1
2-5.
ProASIC3L DC and Switching Characteristics
PUMP
2
supply have no influence on I/O
(Figure 2-1 on page 2-4
Maximum Overshoot/
Undershoot
CCI
.
1.49 V
1.19 V
0.79 V
0.88 V
0.45 V
0.54 V
1.4 V
1.1 V
®
3 device. These
2
and
2 - 3