PIC32MX575F256H-80I Datasheet, PDF (162/236 Pages) Microchip Technology – High-Performance, USB, CAN and Ethernet 32-Bit Flash Microcontrollers

PIC32MX5XX/6XX/7XX
28.3 On-Chip Voltage Regulator
All PIC32MX5XX/6XX/7XX devices’ core and digital
logic are designed to operate at a nominal 1.8V. To
simplify system designs, most devices in the
PIC32MX5XX/6XX/7XX family incorporate an on-chip
regulator providing the required core logic voltage from
VDD.
A low-ESR capacitor (such as tantalum) must be con-
nected to the VCAP/VDDCORE pin (see Figure 28-2).
This helps to maintain the stability of the regulator.
The recommended value for the filter capacitor is
provided in Section 31.1 “DC Characteristics”.
Note:
It is important that the low-ESR capacitor
is placed as close as possible to the
VCAP/VDDCORE pin.
28.3.1 ON-CHIP REGULATOR AND POR
It takes a fixed delay for the on-chip regulator to generate
an output. During this time, designated as TPU, code exe-
cution is disabled. TPU is applied every time the device
resumes operation after any power-down, including
Sleep mode.
If the regulator is disabled, a separate Power-up Timer
(PWRT) is automatically enabled. The PWRT adds a
fixed delay of TPWRT at device start-up. See
Section 31.0 “Electrical Characteristics” for more
information on TPU AND TPWRT.
28.3.2 ON-CHIP REGULATOR AND BOR
PIC32MX5XX/6XX/7XX devices also have a simple
brown-out capability. If the voltage supplied to the reg-
ulator is inadequate to maintain a regulated level, the
regulator Reset circuitry will generate a Brown-out
Reset. This event is captured by the BOR flag bit
(RCON<1>). The brown-out voltage levels are specific
in Section 31.1 “DC Characteristics”.
28.3.3 POWER-UP REQUIREMENTS
The on-chip regulator is designed to meet the power-up
requirements for the device. If the application does not
use the regulator, then strict power-up conditions must
be adhered to. While powering up, VDDCORE must
never exceed VDD by 0.3 volts.
FIGURE 28-2:
CONNECTIONS FOR THE
ON-CHIP REGULATOR
3.3V⁽¹⁾
PIC32MX
VDD
CEFC⁽²⁾
(10 F typ)
VCAP/VDDCORE
VSS
Note 1:
2:
These are typical operating voltages. Refer
to Section 31.1 “DC Characteristics” for
the full operating ranges of VDD and
VDDCORE.
It is important that the low-ESR capacitor
is placed as close as possible to the
VCAP/VDDCORE pin.
DS61156C-page 162
Preliminary
 2010 Microchip Technology Inc.