8
ASC Breakout Board
The two potentiometers (R50 and R52) are tied to VMON7 and VMON8 these can be used to simulate a fault or trip
a comparator (see Figure 4). The slide potentiometers provide a voltage in the range of 0 V to 3.3 V depending on
their position. R51 and R53 are 1 k
Ω
series resistors which allow for the connection of an off-board source directly
to the VMON7 and VMON8 test points. The voltage on either potentiometer can be read out from the A/D converter
using the I
2
C port.
Figure 4. Voltage Monitor Potentiometer Circuits
Temperature Monitoring
The board has PNP transistors mounted in the two corners opposite the main D-SUB connector. The PNP transis-
tors are connected in the beta-compensated PNP temperature monitor configuration (preferred configuration for
temperature monitors), as shown in Figure 5.
Provided the temperature monitors are enabled in the design, the temperature of each sensor can be read out
using I
2
C. The sensors can also be used to simulate over or under-temperature faults.
Figure 5. Temperature Monitor Circuits
The temperature sensors have 150 pF filter capacitors (C3 and C4) connected across the differential signals to
improve noise-immunity that are located close to the ASC device, as shown in Figure 6.
VMON7
VMON8
+3.3
V
+3.3
V
POT1
Sheet [2]
POT2
Sheet [2]
+3.3
V
R51
1k
R50
1k
1
3
2
R53
1k
R52
1k
1
3
2
Temperature Sensor 1
Temperature Sensor 2
TEMP_SE
N
SE1P
TEMP_SE
N
SE1
N
TEMP_SE
N
SE2P
TEMP_SE
N
SE2
N
Q4
2
N
3906
Q3
2
N
3906
