PIC24FJ256GB210 Datasheet, PDF (33/386 Pages) Microchip Technology – 64/100-Pin, 16-Bit Flash Microcontrollers with USB On-The-Go (OTG)

PIC24FJ256GB210 FAMILY
2.4 Voltage Regulator Pins (ENVREG
and VCAP)
Note: This section applies only to PIC24FJ
devices with an on-chip voltage regulator.
The on-chip voltage regulator enable pin (ENVREG)
must always be connected directly to a supply voltage.
Refer to Section 26.2 “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 pin to stabilize the
voltage regulator output voltage. The VCAP pin must not
be connected to VDD, and must use a capacitor of 10 F
connected to ground. The type can be ceramic or
tantalum. A suitable example is the Murata
GRM21BF50J106ZE01 (10 F, 6.3V) or equivalent.
Designers may use Figure 2-3 to evaluate ESR
equivalence of candidate devices.
The placement of this capacitor should be close to
VCAP. It is recommended that the trace length not
exceed 0.25 inch (6 mm). Refer to Section 29.0
“Electrical Characteristics” for additional
information.
FIGURE 2-3:
10
1
FREQUENCY vs. ESR
PERFORMANCE FOR
SUGGESTED VCAP
0.1
0.01
0.001
0.01
0.1
1
10
100
Frequency (MHz)
1000 10,000
Note:
Data for Murata GRM21BF50J106ZE01 shown.
Measurements at 25°C, 0V DC bias.
2.5 ICSP Pins
The PGECx and PGEDx pins are used for In-Circuit
Serial Programming™ (ICSP™) and debugging pur-
poses. It is recommended to keep the trace length
between the ICSP connector and the ICSP pins on the
device as short as possible. If the ICSP connector is
expected to experience an ESD event, a series resistor
is recommended, with the value in the range of a few
tens of ohms, not to exceed 100Ω.
Pull-up resistors, series diodes and capacitors on the
PGECx and PGEDx pins are not recommended as they
will interfere with the programmer/debugger communi-
cations to the device. If such discrete components are
an application requirement, they should be removed
from the circuit during programming and debugging.
Alternatively, refer to the AC/DC characteristics and
timing requirements information in the respective
device Flash programming specification for information
on capacitive loading limits and pin input voltage high
(VIH) and input low (VIL) requirements.
For device emulation, ensure that the “Communication
Channel Select” (i.e., PGECx/PGEDx pins) programmed
into the device matches the physical connections for the
ICSP to the Microchip debugger/emulator tool.
For more information on available Microchip
development tools connection requirements, refer to
Section 27.0 “Development Support”.
 2010 Microchip Technology Inc.
DS39975A-page 33