ProASIC
PLUS
Flash Family FPGAs
V
PP
Programming Supply Pin
This pin may be connected to any voltage between GND
and 16.5 V during normal operation, or it can be left
unconnected.
2
For information on using this pin during
programming,
see
the
PLUS
Devices
application note. Actel recommends
floating the pin or connecting it to V
DDP
.
V
PN
Programming Supply Pin
finite length conductors that distribute the power to the
device. This can be accomplished by providing sufficient
bypass capacitance between the V
PP
and V
PN
pins and
GND (using the shortest paths possible). Without
sufficient bypass capacitance to counteract the
inductance, the V
PP
and V
PN
pins may incur a voltage
spike beyond the voltage that the device can withstand.
This issue applies to all programming configurations.
The solution prevents spikes from damaging the
ProASIC
PLUS
devices. Bypass capacitors are required for
the V
PP
and V
PN
pads. Use a 0.01 µF to 0.1 µF ceramic
capacitor with a 25 V or greater rating. To filter low-
frequency noise (decoupling), use a 4.7 µF (low ESR, <1
<Ω, tantalum, 25 V or greater rating) capacitor. The
capacitors should be located as close to the device pins as
possible (within 2.5 cm is desirable). The smaller, high-
frequency capacitor should be placed closer to the device
pins than the larger low-frequency capacitor. The same
dual-capacitor circuit should be used on both the V
PP
and
V
PN
pins (Figure
This pin may be connected to any voltage between 0.5V
and –13.8 V during normal operation, or it can be left
unconnected.
3
For information on using this pin during
programming,
see
the
PLUS
Devices
application note. Actel recommends
floating the pin or connecting it to GND.
Recommended Design Practice
for V
PN
/V
PP
ProASIC
PLUS
Devices – APA450, APA600,
APA750, APA1000
Bypass capacitors are required from V
PP
to GND and V
PN
to GND for all ProASIC
PLUS
devices during programming.
During the erase cycle, ProASIC
PLUS
devices may have
current surges on the V
PP
and V
PN
power supplies. The
only way to maintain the integrity of the power
distribution to the ProASIC
PLUS
device during these
current surges is to counteract the inductance of the
2.5cm
V
PP
ProASIC
PLUS
Devices – APA075, APA150,
APA300
These devices do not require bypass capacitors on the V
PP
and V
PN
pins as long as the total combined distance of
the programming cable and the trace length on the
board is less than or equal to 30 inches. Note: For trace
lengths greater than 30 inches, use the bypass capacitor
recommendations in the previous section.
+ _
0.1µF
to
0.01µF
4.7µF
+
Programming
Header
or
Supplies
_ +
0.1µF
to
0.01µF
Actel
PLUS
ProASIC
Device
V
PN
4.7µF
+
Figure 1-49 •
ProASIC
PLUS
V
PP
and V
PN
Capacitor Requirements
2. There is a nominal 40 kΩ pull-up resistor on V
PP
.
3. There is a nominal 40 kΩ pull-down resistor on
V
PN
.
1 -7 4
v5.2
ACTEL [ Actel Corporation ]
