PIC18F45K80-I Datasheet, PDF (474/622 Pages) Microchip Technology – 28/40/44/64-Pin, Enhanced Flash Microcontrollers with ECAN and nanoWatt XLP Technology

PIC18F66K80 FAMILY
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
VDD. 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 VDDCORE/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 VDD.
The voltage levels for VDD must not exceed the speci-
fied VDDCORE levels. A 0.1 F capacitor should be
connected to the VDDCORE/VCAP pin.
On the PIC18FXXKXX devices, the overall voltage
budget is very tight. The regulator should operate the
device down to 1.8V. When VDD drops below 3.3V, the
regulator no longer regulates, but the output voltage
follows the input until VDD 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
5V⁽¹⁾
PIC18F66K80
VDD
VDDCORE/VCAP
CF
VSS
3.3V⁽¹⁾
0.1 F
Capacitor
PIC18LF66K80
VDD
VDDCORE/VCAP⁽²⁾
VSS
Note 1:
2:
These are typical operating voltages. For the full
operating ranges of VDD and VDDCORE, see
Section 31.1 “DC Characteristics: Supply
Voltage PIC18F66K80 Family (Industrial/
Extended)”.
When the regulator is disabled, VDDCORE/VCAP
must be connected to a 0.1 F capacitor.
DS39977F-page 474
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