PIC18F45J10 FAMILY
2.4
Voltage Regulator Pins
(VCAP/VDDCORE)
2.5
ICSP Pins
The PGC and PGD pins are used for In-Circuit Serial
Programming (ICSP) and debugging purposes. 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 recom-
mended, with the value in the range of a few tens of
ohms, not to exceed 100Ω.
When the regulator is enabled (F devices), 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 (10 μF typical) connected to
ground. The type can be ceramic or tantalum. A suitable
example is the Murata GRM21BF50J106ZE01 (10 μF,
6.3V) or equivalent. Designers may use Figure 2-3 to
evaluate ESR equivalence of candidate devices.
Pull-up resistors, series diodes and capacitors on the
PGC and PGD pins are not recommended as they will
interfere with the programmer/debugger com-
munications 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.
It is recommended that the trace length not exceed
0.25 inch (6 mm). Refer to Section 24.0 “Electrical
Characteristics” for additional information.
When the regulator is disabled (LF devices), the
VCAP/VDDCORE pin must be tied to a voltage supply at
the VDDCORE level. Refer to Section 24.0 “Electrical
Characteristics” for information on VDD and
VDDCORE.
For device emulation, ensure that the “Communication
Channel Select” (i.e., PGC/PGD pins) programmed
into the device matches the physical connections for
the ICSP to the MPLAB® ICD 2, MPLAB ICD 3 or
REAL ICE™ emulator.
FIGURE 2-3:
FREQUENCY vs. ESR
PERFORMANCE FOR
SUGGESTED VCAP
10
1
For more information on the ICD 2, ICD 3 and REAL ICE
emulator connection requirements, refer to the following
documents that are available on the Microchip web site.
• “MPLAB® ICD 2 In-Circuit Debugger User’s
Guide” (DS51331)
0.1
• “Using MPLAB® ICD 2” (poster) (DS51265)
• “MPLAB® ICD 2 Design Advisory” (DS51566)
• “Using MPLAB® ICD 3” (poster) (DS51765)
• “MPLAB® ICD 3 Design Advisory” (DS51764)
0.01
0.001
0.01
0.1
1
10
100
1000 10,000
• “MPLAB® REAL ICE™ In-Circuit Emulator User’s
Guide” (DS51616)
• “Using MPLAB® REAL ICE™ In-Circuit Emulator”
Frequency (MHz)
Note:
Data for Murata GRM21BF50J106ZE01 shown.
Measurements at 25°C, 0V DC bias.
(poster) (DS51749)
© 2009 Microchip Technology Inc.
DS39682E-page 25
MICROCHIP [ MICROCHIP ]
