PIC32MX1XX Datasheet, PDF (28/320 Pages) Microchip Technology – 32-bit Microcontrollers (up to 128 KB Flash and 32 KB SRAM) with Audio and Graphics Interfaces, USB, and Advanced Analog

PIC32MX1XX/2XX
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 (VCAP)
2.3.1 INTERNAL REGULATOR MODE
A low-ESR (1 ohm) capacitor is required on the VCAP
pin, which is used to stabilize the internal voltage regu-
lator output. The VCAP pin must not be connected to
VDD, and must have a CEFC capacitor, with at least a
6V rating, connected to ground. The type can be
ceramic or tantalum. Refer to Section 29.0 “Electrical
Characteristics” for additional information on CEFC
specifications.
2.4 Master Clear (MCLR) Pin
The MCLR pin provides for 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 (VIH 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:
VDD
EXAMPLE OF MCLR PIN
CONNECTIONS
R⁽¹⁾
JP
C⁽³⁾
R1⁽²⁾
MCLR
PIC32
Note 1: R ≤10 kΩ is recommended. A suggested start-
ing value is 10 kΩ. Ensure that the MCLR pin
VIH 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
VIH 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 POR.
DS61168D-page 28
Preliminary
© 2011-2012 Microchip Technology Inc.