ProASIC3 DC and Switching Characteristics
2-4
Revision 13
Internal Power-Up Activation Sequence
1. Core
2. Input buffers
Output buffers, after 200 ns delay from input buffer activation
Thermal Characteristics
Introduction
The temperature variable in the Microsemi Designer software refers to the junction temperature, not the
ambient temperature. This is an important distinction because dynamic and static power consumption
cause the chip junction to be higher than the ambient temperature.
EQ 1 can be used to calculate junction temperature.
TJ = Junction Temperature = T + TA
EQ 1
where:
TA = Ambient Temperature
T = Temperature gradient between junction (silicon) and ambient T = ja * P
ja = Junction-to-ambient of the package. ja numbers are located in Table 2-5. P = Power dissipation
Figure 2-1 I/O State as a Function of VCCI and VCC Voltage Levels
Region 1: I/O buffers are OFF
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.
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
VCC
VCC = 1.425 V
Region 1: I/O Buffers are OFF
Activation trip point:
Va = 0.85 V ± 0.25 V
Deactivation trip point:
Vd = 0.75 V ± 0.25 V
Activation trip point:
Va = 0.9 V ± 0.3 V
Deactivation trip point:
Vd = 0.8 V ± 0.3 V
VCC = 1.575 V
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 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.
where VT can be from 0.58 V to 0.9 V (typically 0.75 V)
VCCI
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.
VCC = VCCI + VT