Datasheet
PIC18F66K80 FAMILY
DS39977F-page 474 2010-2012 Microchip Technology Inc.
28.3 On-Chip Voltage Regulator
All of the PIC18F66K80 family devices power their core
digital logic at a nominal 3.3V. For designs that are
required to operate at a higher typical voltage, such as
5V, all family devices incorporate two on-chip regula-
tors that allows the device to run its core logic from
V
DD. Those regulators are:
• Normal on-chip regulator
• Ultra Low-Power, on-chip regulator
The hardware configuration of these regulators are the
same and are explained in
Section 28.3.1 “Regulator
Enable Mode (PIC18FXXKXX devices)”
. The regula-
tors’ only differences relate to when the device enters
Sleep, as explained in
Section 28.3.1 “Regulator
Enable Mode (PIC18FXXKXX devices)”
.
28.3.1 REGULATOR ENABLE MODE
(PIC18FXXKXX DEVICES)
On PIC18FXXKXX devices, the regulator is enabled
and a low-ESR filter capacitor must be connected to
the V
DDCORE/VCAP pin (see Figure 28-2). This helps
maintain the regulator’s stability. The recommended
value for the filter capacitor is given in
Section 31.1
“DC Characteristics: Supply Voltage PIC18F66K80
Family (Industrial/Extended)”.
28.3.2 REGULATOR DISABLE MODE
(PIC18LFXXKXX DEVICES)
On PIC18LFXXKXX devices, the regulator is disabled
and the power to the core is supplied directly by V
DD.
The voltage levels for V
DD must not exceed the speci-
fied V
DDCORE levels. A 0.1 F capacitor should be
connected to the V
DDCORE/VCAP pin.
On the PIC18FXXKXX devices, the overall voltage
budget is very tight. The regulator should operate the
device down to 1.8V. When V
DD drops below 3.3V, the
regulator no longer regulates, but the output voltage
follows the input until V
DD reaches 1.8V. Below this
voltage, the output of the regulator output may drop
to 0V.
FIGURE 28-2: CONNECTIONS FOR THE F
AND LF PARTS
VDD
VDDCORE/VCAP
VSS
CF
5V
(1)
VDD
VDDCORE/VCAP
(2)
V
SS
3.3V
(1)
Note 1: These are typical operating voltages. For the full
operating ranges of V
DD and VDDCORE, see
Section 31.1 “DC Characteristics: Supply
Voltage PIC18F66K80 Family (Industrial/
Extended)”
.
2: When the regulator is disabled, VDDCORE/VCAP
must be connected to a 0.1
F capacitor.
PIC18F66K80
PIC18LF66K80
0.1 F
Capacitor