Microchip Technology MA330018 Data Sheet

© 2007-2012 Microchip Technology Inc.

DS70291G-page  17

Getting started with the dsPIC33FJ32MC302/304, 
dsPIC33FJ64MCX02/X04 and dsPIC33FJ128MCX02/
X04 family of 16-bit Digital Signal Controllers (DSC) 
requires attention to a minimal set of device pin 
connections before proceeding with development. The 
following is a list of pin names, which must always be 
connected:
• All V

DD

 and V

SS

 pins 

 

(see 

• All AV

DD

 and AV

SS

 pins (regardless if ADC module 

is not used) 

 

(see 

• V

CAP

 

 

(see 

) 

• MCLR pin 

 

(see 

• PGECx/PGEDx pins used for In-Circuit Serial 

Programming™ (ICSP™) and debugging purposes 
(see 

)

• OSC1 and OSC2 pins when external oscillator 

source is used 

 

(see 

)

Additionally, the following pins may be required:
• V

REF

+/V

REF

- pins used when external voltage 

reference for ADC module is implemented

The use of decoupling capacitors on every pair of 
power supply pins, such as V

DD

, V

SS

, AV

DD

 and 

AV

SS

 is required. 

Consider the following criteria when using decoupling 
capacitors:
• Value and type of capacitor: Recommendation 

of 0.1 µF (100 nF), 10-20V. This capacitor should 
be a low-ESR and have resonance frequency in 
the range of 20 MHz and higher. It is 
recommended that ceramic capacitors be used.

• Placement on the printed circuit board: The 

decoupling capacitors should be placed as close 
to the pins as possible. It is recommended to 
place the capacitors on the same side of the 
board as the device. If space is constricted, the 
capacitor can be placed on another layer on the 
PCB using a via; however, ensure that the trace 
length from the pin to the capacitor is within 
one-quarter inch (6 mm) in length.

• Handling high frequency noise: If the board is 

experiencing high frequency noise, upward of 
tens of MHz, add a second ceramic-type capacitor 
in parallel to the above described decoupling 
capacitor. The value of the second capacitor can 
be in the range of 0.01 µF to 0.001 µF. Place this 
second capacitor next to the primary decoupling 
capacitor. In high-speed circuit designs, consider 
implementing a decade pair of capacitances as 
close to the power and ground pins as possible. 
For example, 0.1 µF in parallel with 0.001 µF.

• Maximizing performance: On the board layout 

from the power supply circuit, run the power and 
return traces to the decoupling capacitors first, 
and then to the device pins. This ensures that the 
decoupling capacitors are first in the power chain. 
Equally important is to keep the trace length 
between the capacitor and the power pins to a 
minimum thereby reducing PCB track inductance.

Note 1: This data sheet summarizes the features 

of the dsPIC33FJ32MC302/304, 
dsPIC33FJ64MCX02/X04 and 
dsPIC33FJ128MCX02/X04 family of 
devices. It is not intended to be a 
comprehensive reference source. To 
complement the information in this data 
sheet, refer to the “dsPIC33F/PIC24H 
Family Reference Manual”. Please see 
the Microchip web site 
(

www.microchip.com

) for the latest 

dsPIC33F/PIC24H Family Reference 
Manual sections.

2: Some registers and associated bits 

described in this section may not be 
available on all devices. Refer to 

 in 

this data sheet for device-specific register 
and bit information.

The AV

DD

 and AV

SS

 pins must be 

connected independent of the ADC 
voltage reference source.