Microchip Technology MA330025-1 Data Sheet

 2009-2012 Microchip Technology Inc.

DS70616G-page 31

Getting started with the 16-bit DSCs and microcontrollers
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

• 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

USB3V3

 pin is used when utilizing the USB 

module. If the USB module is not used, V

USB3V3

 

must be connected to V

DD

.

• V

REF

+/V

REF

- pin is 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

, V

USB3V3

,

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 to 
use ceramic capacitors.

• 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, above tens of 
MHz, add a second ceramic-type capacitor in 
parallel to the above described decoupling capaci-
tor. 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 implement-
ing 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

dsPIC33EPXXX(GP/MC/MU)806/810/814

and PIC24EPXXX(GP/GU)810/814 fami-

lies of devices. It is not intended to be a

comprehensive reference source. To

complement the information in this data

sheet, refer to the related section of the

“dsPIC33E/PIC24E Family Reference

Manual”, which is available from the

www.microchip.com

)

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. The voltage
difference between AV

DD

 and V

DD

 cannot

exceed 300 mV at any time during
operation or start-up.