M1AFS250-FGG256I Actel Corporation, M1AFS250-FGG256I Datasheet - Page 113

• Manufacturer Part Number: M1AFS250-FGG256I
• Description: Actel Fusion Family Of Mixed Signal Fpgas
• Manufacturer: Actel Corporation

Fusion uses a remote diode as a temperature sensor. The Fusion Temperature Monitor uses a
differential input; the AT pin and ATRTN (AT Return) pin are the differential inputs to the Temperature
Monitor. There is one Temperature Monitor in each Quad. A simplified block diagram is shown in
Figure
Figure 2-78 • Block Diagram for Temperature Monitor Circuit
The Fusion approach to measuring temperature is forcing two different currents through the diode with a
ratio of 10:1. The switch that controls the different currents is controlled by the Temperature Monitor
Strobe signal, TMSTB. Setting TMSTB to '1' will initiate a Temperature reading. The TMSTB should
remain '1' until the ADC finishes sampling the voltage from the Temperature Monitor. The minimum
sample time for the Temperature Monitor cannot be less than the minimum strobe high time minus the
setup time.
Figure 2-79 • Timing Diagram for the Temperature Monitor Strobe Signal
2-78.
Figure 2-79
ADCSTART
10
TMSTBx
ATx
ATRTNxy
μA
VADC
shows the timing diagram.
TMSTBx
t
100
TMSLO
μA
∆V
–
+
t
R e v i s i o n 1
VDD33A
TMSSET
+
–
12.5 X
t
TMSHI
ADC should start
sampling at this point
Actel Fusion Family of Mixed Signal FPGAs
VADC
for MUX Channel
(refer Table 2-36
to Analog MUX
Number)
2- 97