MCP1316 Microchip Technology, MCP1316 Datasheet - Page 33

• Manufacturer Part Number: MCP1316
• Description: Voltage Supervisor
• Manufacturer: Microchip Technology

5.7
Some microcontrollers have bidirectional Reset pins.
Depending on the current drive capability of the control-
ler pin, an indeterminate logic level may result if there
is a logic conflict. This can be avoided by adding a
4.7 k
MCP131X/2X (Figure 5-7). If there are other compo-
nents in the system that require a Reset signal, they
should be buffered so as not to load the Reset line. If
the other components are required to follow the Reset
I/O of the microcontroller, the buffer should be con-
nected as shown with the solid line.
FIGURE 5-7:
MCP131X/2X Push-Pull outputs to a
Bidirectional Reset I/O.
© 2005 Microchip Technology Inc.
MCP13XX
V
DD
GND
resistor in series with the output of the
RST
Controllers and Processors With
Bidirectional I/O Pins
4.7 k
Interfacing the
Buffer
PICmicro®
MCLR
GND
MCU
Buffered Reset
To Other System
Components
5.8
The MCP131X/2X Reset output is valid to V
Below this 1.0V, the output becomes an "open circuit"
and does not sink or source current. This means
CMOS logic inputs to the microcontroller will be floating
at an undetermined voltage. Most digital systems are
completely shut down well above this voltage.
However, in situations where the Reset signal must be
maintained valid to V
required.
For devices where the Reset signal is active-low, a
pull-down resistor must be connected from the
MCP131X/2X Reset pin(s) to ground to discharge stray
capacitances and hold the output low (Figure 5-8).
Similarly for devices where the Reset signal is
active-high, a pull-up resistor to V
ensure a valid high Reset signal for V
This resistor value, though not critical, should be
chosen such that it does not appreciably load the Reset
pin(s) under normal operation (100 k
for most applications).
FIGURE 5-8:
Reset pin output state as V
RESET Signal Integrity During
Power-Down
MCP13XX
GND
V
V
DD
DD
MCP131X/2X
RST
Ensuring a valid active-low
DD
= 0V, external circuitry is
DD
approaches 0V.
R
100 k
DD
1
DS21985A-page 33
DD
will be suitable
is required to
below 1.0V.
DD
= 1.0V.