PIC18F2220 MICROCHIP [Microchip Technology], PIC18F2220 Datasheet - Page 227

• Manufacturer Part Number: PIC18F2220
• Description: 28/40/44-Pin High-Performance, Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

20.7
When a comparator is active and the device is placed
in a power managed mode, the comparator remains
active and the interrupt is functional if enabled. This
interrupt will wake-up the device from a power
managed mode when enabled. Each operational com-
parator will consume additional current, as shown in
the comparator specifications. To minimize power
consumption while in a power managed mode, turn off
the comparators (CM<2:0> = 111) before entering the
power managed modes. If the device wakes up from a
power managed mode, the contents of the CMCON
register are not affected.
20.8
A device Reset forces the CMCON register to its Reset
state, causing the comparator module to be in the Com-
parator Reset mode (CM<2:0> = 111). This ensures
that all potential inputs are analog inputs. Device cur-
rent is minimized when digital inputs are present at
Reset time. The comparators will be powered down
during the Reset interval.
FIGURE 20-4:
 2003 Microchip Technology Inc.
Comparator Operation in Power
Managed Modes
Effects of a Reset
VA
Legend:
R
S
COMPARATOR ANALOG INPUT MODEL
< 10k
C
V
I
R
R
VA
A
LEAKAGE
PIN
T
IC
S
IN
C
5 pF
PIN
= Input Capacitance
= Threshold Voltage
= Leakage Current at the pin due to various junctions
= Interconnect Resistance
= Source Impedance
= Analog Voltage
PIC18F2220/2320/4220/4320
V
DD
V
V
T
T
= 0.6V
= 0.6V
20.9
A simplified circuit for an analog input is shown in
Figure 20-4. Since the analog pins are connected to a
digital output, they have reverse biased diodes to V
and V
V
more than 0.6V, one of the diodes is forward biased
and a latch-up condition may occur. A maximum source
impedance of 10 k
sources.
SS
and V
V
SS
SS
. Therefore, the analog input must be between
Analog Input Connection
Considerations
I
±500 nA
LEAKAGE
DD
. If the input voltage exceeds this range by
R
IC
is recommended for the analog
Comparator
Input
DS39599C-page 225
DD