IMP1834/A/D
Application Information
Reset Output Signal
Reset output signals are valid as long as either voltage at 5VIN
or 3.3VIN is above 1.2V. In addition, the IMP1834 has push-pull
outputs that can remain valid below a 1.2V input level. To sink
current below 1.2V, a resistor should be connected from the reset
output to ground. This resistor guarantees a valid reset signal
down to 0V. A 100kΩ value is suggested.
5V
3.3V
IMP1834A
8
7
6
5
1
2
3
4
10kΩ
5VIN
3.3VIN
10kΩ
The IMP1834A open drain reset outputs require pull-up resistors
and must be low enough in value to pull the output into a HIGH
state. Resistor value is not critical in most applications and a value
of 10kΩ is suggested. See Figure 5 and Figure 6.
5VRESET 3.3VRESET
5VTOL
GND
3.3VTOL
PBRST
The IMP1834A open drain reset outputs can be connected to the
same potential through a single pull up resistor. In this configura-
tion a failure on either supply will generate an active LOW reset.
If the outputs are pulled-up to different voltages, the reset outputs
(pin 2 and pin 7) should not be connected. See Figure 7.
1834_07.eps
Figure 6. IMP1834A Open Drain Output Pull-Up Resistor
5V
3.3V
5V or 3.3V
IMP1834A
µP
Input
RESET
10kΩ
8
7
6
5
1
2
3
4
5VIN
3.3VIN
100kΩ
5VRESET 3.3VRESET
1834_06.eps
5VTOL
GND
3.3VTOL
PBRST
Figure 5. IMP1834 RESET Valid to 0V
1834_08.eps
Figure 7. IMP1834A Wired “OR” Connection
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© 1999 IMP, Inc.
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