Datasheet

PIC32MX5XX/6XX/7XX
DS61156G-page 44 © 2009-2011 Microchip Technology Inc.
FIGURE 2-1: RECOMMENDED
MINIMUM CONNECTION
2.2.1 BULK CAPACITORS
The use of a bulk capacitor is recommended to improve
power supply stability. Typical values range from 4.7 µF
to 47 µF. This capacitor should be located as close to
the device as possible.
2.3 Capacitor on Internal Voltage
Regulator (V
CAP/VCORE)
2.3.1 INTERNAL REGULATOR MODE
A low-ESR (1 ohm) capacitor is required on the
VCAP/VCORE pin, which is used to stabilize the internal
voltage regulator output. The V
CAP/VCORE pin must not
be connected to VDD, and must have a CEFC capaci-
tor, with at least a 6V rating, connected to ground. The
type can be ceramic or tantalum. Refer to Section 31.0
“Electrical Characteristics” for additional information
on C
EFC specifications.
2.4 Master Clear (MCLR) Pin
The MCLR pin provides two specific device
functions:
• Device Reset
• Device Programming and Debugging
Pulling The MCLR
pin low generates a device Reset.
Figure 2-2 illustrates a typical MCLR
circuit. During
device programming and debugging, the resistance
and capacitance that can be added to the pin must
be considered. Device programmers and debuggers
drive the MCLR
pin. Consequently, specific voltage
levels (V
IH and VIL) and fast signal transitions must
not be adversely affected. Therefore, specific values
of R and C will need to be adjusted based on the
application and PCB requirements.
For example, as illustrated in Figure 2-2, it is
recommended that the capacitor C, be isolated from
the MCLR
pin during programming and debugging
operations.
Place the components illustrated in Figure 2-2 within
one-quarter inch (6 mm) from the MCLR
pin.
FIGURE 2-2: EXAMPLE OF MCLR PIN
CONNECTIONS
PIC32
VDD
VSS
VDD
VSS
VSS
VDD
AVDD AVSS VDD VSS
C
R
V
DD
MCLR
0.1 µF
Ceramic
VCAP/VCORE
10 Ω
R1
CBP
0.1 µF
Ceramic
C
BP
0.1 µF
Ceramic
C
BP
0.1 µF
Ceramic
C
BP
0.1 µF
Ceramic
C
BP
CEFC
Note 1: R ≤ 10 kΩ is recommended. A suggested start-
ing value is 10 kΩ. Ensure that the MCLR
pin
V
IH and VIL specifications are met.
2: R1 ≤ 470Ω will limit any current flowing into
MCLR
from the external capacitor C, in the
event of MCLR
pin breakdown, due to
Electrostatic Discharge (ESD) or Electrical
Overstress (EOS). Ensure that the MCLR
pin
V
IH and VIL specifications are met.
3: The capacitor can be sized to prevent uninten-
tional Resets from brief glitches or to extend
the device Reset period during the POR.
C
R1
R
V
DD
MCLR
PIC32
JP