Spartan-3E FPGA Industrial Micromodule
User Manual
4 V. The maximum supply voltage is 5.5 V.
The recommended maximum continuous
supply current is 1.5 A.
USB Power Supply
The module is powered by the USB con-
nector if the following conditions are met:
■
the module is equipped with an USB
connector,
■
the module is connected to a USB bus,
■
no power supply is provided by the B2B
connectors.
In this case, other components (e.g. ex-
tension or carrier boards) may also be
powered by the corresponding 5 Volt line
(5V) of the B2B connector J5.
On-board Power Rails
Three on-board voltage regulators provide
the following power supply rails needed by
the components on the micromodule:
■
1.2 V, 1 A max
■
2.5 V, 1 A max
■
3.3 V, 1 A max
The power rails are available for the FPGA
and can be shared with a baseboard by the
corresponding
lines of the B2B connect-
ors J4 and J5. Please note that the
power
consumption of the FPGA is highly de-
pendent on the design
actually loaded.
So please use a tool like Xilinx Xpower to
determine the expected power consump-
tion.
Even if the provided voltages of the mod-
ule are not used on the baseboard, it is re-
commended to bypass them to ground
with 10 nF - 100 nF capacitors.
I/O Banks Power Supply
The Spartan-3E architecture organizes
I/Os into four I/O banks (see Table 3).
Bank
Supply
Voltage (V)
Min
(V)
Max
(V)
B0
VccIO
1.2
3.3
B1
2,5
-
-
B2
3,3
-
-
B3
3,3
-
-
Table 3: I/O banks power supply.
Voltage for banks B1, B2 and B3 is fixed
respectively to 2,5 V, 3,3 V and 3,3 V.
Voltage VccIO for bank B0 shall span from
1.2 V to 3.3 V. VccIO can be supplied
either externally or internally to the micro-
module.
Warning!
Spartan-3 I/Os are not 5 V tol-
erant. Applying more than the recommen-
ded operating voltages at any pin, results
in a damaged FPGA (see Xilinx Answer
AR#19146).
Externally Supplied VccIO
VccIO can be externally supplied over the
B2B connector J4. If bank B0 is not used,
then VccIO can be left open.
Internally Supplied VccIO
If VccIO is
not
externally supplied, it can
be internally supplied by
one
of the intern-
al power rails of 2.5 V and 3.3 V. This is
possible by short-circuiting
one
of the two
pad pairs placed on the right of connector
J4 at the top right corner of the bottom
side of the micromodule.
Figure 9 shows how to short-circuit VccIO
to internal 3.3 V power rail.
Figure 10 shows how to short-circuit VccIO
to internal 2.5 V power rail.
Trenz Electronic GmbH
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