M1AFS600-PQ208 Datasheet, PDF (112/334 Pages) Microsemi Corporation – Fusion Family of Mixed Signal FPGAs

Device Architecture
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 2-77.
VDD33A
10 μA
100 μA
TMSTBx
ATx
+
∆V
–
ATRTNxy
+
12.5 X
–
VADC
to Analog MUX
(refer Table 2-36
for MUX Channel
Number)
Figure 2-77 • 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 2-78 shows the timing diagram.
TMSTBx
VADC
t_TMSLO
t_TMSSET
t_TMSHI
ADC should start
sampling at this point
ADCSTART
Figure 2-78 • Timing Diagram for the Temperature Monitor Strobe Signal
Note: When the IEEE 1149.1 Boundary Scan EXTEST instruction is executed, the AG pad drive
strength ceases and becomes a 1 µA sink into the Fusion device.
2-96
Revision 4