A3PE1500-PQG208I Datasheet, PDF (18/166 Pages) Microsemi Corporation – ProASIC3E Flash Family FPGAs with Optional Soft ARM Support

ProASIC3E DC and Switching Characteristics
PLL Behavior at Brownout Condition
Microsemi recommends using monotonic power supplies or voltage regulators to ensure proper
power-up behavior. Power ramp-up should be monotonic at least until VCC and VCCPLXL exceed
brownout activation levels. The VCC activation level is specified as 1.1 V worst-case (see Figure 2-1 on
page 2-4 for more details).
When PLL power supply voltage and/or VCC levels drop below the VCC brownout levels (0.75 V ± 0.25
V), the PLL output lock signal goes low and/or the output clock is lost. Refer to the "Power-Up/-Down
Behavior of Low Power Flash Devices" chapter of the ProASIC3E FPGA Fabric User’s Guide for
information on clock and lock recovery.
Internal Power-Up Activation Sequence
1. Core
2. Input buffers
3. Output buffers, after 200 ns delay from input buffer activation
VCC
VCC = 1.575 V
VCC = 1.425 V
Activation trip point:
V_a = 0.85 V ± 0.25 V
Deactivation trip point:
V_d = 0.75 V ± 0.25 V
VCC = VCCI + VT
where VT can be from 0.58 V to 0.9 V (typically 0.75 V)
Region 1: I/O Buffers are OFF
Region 4: I/O
buffers are ON.
I/Os are functional
(except differential
but slower because VCCI
is below specification. For the
same reason, input buffers do not
meet VIH / VIL levels, and output
buffers do not meet VOH / VOL levels.
Region 5: I/O buffers are ON
and power supplies are within
specification.
I/Os meet the entire datasheet
and timer specifications for
speed, VIH / VIL, VOH / VOL,
etc.
Region 2: I/O buffers are ON.
I/Os are functional (except differential inputs)
but slower because VCCI / VCC are below
specification. For the same reason, input
buffers do not meet VIH / VIL levels, and
output buffers do not meet VOH / VOL levels.
Region 3: I/O buffers are ON.
I/Os are functional; I/O DC
specifications are met,
but I/Os are slower because
the VCC is below specification.
Region 1: I/O buffers are OFF
Activation trip point:
V_a = 0.9 V ± 0.3 V
Deactivation trip point:
V_d = 0.8 V ± 0.3 V
Min VCCI datasheet specification
voltage at a selected I/O
standard; i.e., 1.425 V or 1.7 V
or 2.3 V or 3.0 V
Figure 2-1 • I/O State as a Function of VCCI and VCC Voltage Levels
VCCI
2-4
Revision 14