2 Note

Un-Powered Testing (MDA)
307507-002 19
The resistance of the switch is equal to approximately 40 ohm in the ON state and is
infinite in the OFF state. In an isolated environment, the ON state voltage measured
at the signal would be approximately 44 mV as a voltage divider exists between the
40 ohm switch resistance and the 500 ohm resistance of the source termination.
It has been observed that the OFF state voltage doesn’t reach the 600 mV level that
circuit theory would lead one to expect. This is due to the influence of other on-board
devices that cause the level to settle at approximately 250 mV.
Figure 4 - Instrument Setup for Low Side Switch
GND
VCCP
Signal
Board VCCP-
GND Capacitance
Hcontrol
Lcontrol
G Bus
Connection
A Bus
+1.2V
DC DC
S Bus
+600mv
MV
I Bus
L Bus
500 ohm S Bus
Termination
1K ohm
Figure 5 - Instrument Setup for High Side Switch
GND
VCCP
Signal
Board VCCP-
GND Capacitance
Hcontrol
Lcontrol
G Bus
Connection
A Bus
+1.2V
DC DC
S Bus
+600mv
MV
I Bus
L Bus
500 ohm S Bus
Termination
1K ohm
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