PIC18F24 MICROCHIP [Microchip Technology], PIC18F24 Datasheet - Page 255

• Manufacturer Part Number: PIC18F24
• Description: 28/40-Pin High-Performance, Enhanced Flash Microcontrollers with CAN Module
• Manufacturer: MICROCHIP [Microchip Technology]

21.7
When a comparator is active and the device is placed
in Sleep mode, the comparator remains active and the
interrupt is functional if enabled. This interrupt will
wake-up the device from Sleep mode when enabled.
While the comparator is powered up, higher Sleep
currents than shown in the power-down current
specification will occur. Each operational comparator
will consume additional current, as shown in the com-
parator specifications. To minimize power consumption
while in Sleep mode, turn off the comparators,
CM<2:0> = 111, before entering Sleep. If the device
wakes up from Sleep, the contents of the CMCON
register are not affected.
FIGURE 21-4:
 2004 Microchip Technology Inc.
Comparator Operation During
Sleep
VA
Legend:
R
S
ANALOG INPUT MODEL
< 10k
A
IN
C
V
I
R
R
VA
LEAKAGE
PIN
T
IC
S
C
5 pF
PIN
=
=
=
=
=
=
Input Capacitance
Threshold Voltage
Leakage Current at the pin due to various junctions
Interconnect Resistance
Source Impedance
Analog Voltage
V
DD
V
V
T
T
= 0.6V
= 0.6V
21.8
A device Reset forces the CMCON register to its Reset
state, causing the comparator module to be in the
Comparator Reset mode, CM<2:0> = 000. This
ensures that all potential inputs are analog inputs.
Device current is minimized when analog inputs are
present at Reset time. The comparators will be
powered down during the Reset interval.
21.9
A simplified circuit for an analog input is shown in
Figure 21-4. Since the analog pins are connected to a
digital output, they have reverse biased diodes to V
and V
V
range by more than 0.6V in either direction, one of the
diodes is forward biased and a latch-up condition may
occur. A maximum source impedance of 10 k
recommended for the analog sources. Any external
component connected to an analog input pin, such as
a capacitor or a Zener diode, should have very little
leakage current.
SS
and V
SS
. The analog input, therefore, must be between
Effects of a Reset
Analog Input Connection
Considerations
I
V
LEAKAGE
500 nA
DD
SS
. If the input voltage deviates from this
R
IC
PIC18FXX8
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