PIC18F45K80-I Datasheet, PDF (47/622 Pages) Microchip Technology – 28/40/44/64-Pin, Enhanced Flash Microcontrollers with ECAN and nanoWatt XLP Technology

PIC18F66K80 FAMILY
2.4 Voltage Regulator Pins (ENVREG
and VCAP/VDDCORE)
The on-chip voltage regulator enable pin, ENVREG,
must always be connected directly to either a supply
voltage or to ground. Tying ENVREG to VDD enables
the regulator, while tying it to ground disables the
regulator. Refer to Section 28.3 “On-Chip Voltage
Regulator” for details on connecting and using the
on-chip regulator.
When the regulator is enabled, a low-ESR (< 5Ω)
capacitor is required on the VCAP/VDDCORE pin to
stabilize the voltage regulator output voltage. The
VCAP/VDDCORE pin must not be connected to VDD and
must use a capacitor of 10 µF connected to ground. The
type can be ceramic or tantalum. Suitable examples of
capacitors are shown in Table 2-1. Capacitors with
equivalent specifications can be used.
Designers may use Figure 2-3 to evaluate ESR
equivalence of candidate devices.
It is recommended that the trace length not exceed
0.25 inch (6 mm). Refer to Section 31.0 “Electrical
Characteristics” for additional information.
When the regulator is disabled, the VCAP/VDDCORE pin
must be tied to a voltage supply at the VDDCORE level.
Refer to Section 31.0 “Electrical Characteristics” for
information on VDD and VDDCORE.
Some PIC18FXXKXX families, or some devices within
a family, do not provide the option of enabling or
disabling the on-chip voltage regulator:
• Some devices (with the name, PIC18LFXXKXX)
permanently disable the voltage regulator.
These devices do not have the ENVREG pin and
require a 0.1 F capacitor on the VCAP/VDDCORE
pin. The VDD level of these devices must comply
with the “voltage regulator disabled” specification
for Parameter D001, in Section 31.0 “Electrical
Characteristics”.
• Some devices permanently enable the voltage
regulator.
These devices also do not have the ENVREG pin.
The 10 F capacitor is still required on the
VCAP/VDDCORE pin.
FIGURE 2-3:
10
FREQUENCY vs. ESR
PERFORMANCE FOR
SUGGESTED VCAP
1
0.1
0.01
0.001
0.01
0.1
1
10
100
Frequency (MHz)
1000 10,000
Note:
Typical data measurement at 25°C, 0V DC bias.
TABLE 2-1:
Make
TDK
TDK
Panasonic
Panasonic
Murata
Murata
.
SUITABLE CAPACITOR EQUIVALENTS
Part #
Nominal
Capacitance
Base Tolerance Rated Voltage Temp. Range
C3216X7R1C106K
C3216X5R1C106K
ECJ-3YX1C106K
ECJ-4YB1C106K
GRM32DR71C106KA01L
GRM31CR61C106KC31L
10 µF
10 µF
10 µF
10 µF
10 µF
10 µF
±10%
±10%
±10%
±10%
±10%
±10%
16V
-55 to 125ºC
16V
-55 to 85ºC
16V
-55 to 125ºC
16V
-55 to 85ºC
16V
-55 to 125ºC
16V
-55 to 85ºC
 2010-2012 Microchip Technology Inc.
DS39977F-page 47