Datasheet

LPC2101_02_03_4 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 04 — 2 June 2009 30 of 37
NXP Semiconductors
LPC2101/02/03
Single-chip 16-bit/32-bit microcontrollers
10.2 XTAL and RTC Printed Circuit Board (PCB) layout guidelines
The crystal should be connected on the PCB as close as possible to the oscillator input
and output pins of the chip. Take care that the load capacitors C
x1
and C
x2
, and C
x3
in
case of third overtone crystal usage, have a common ground plane. The external
components must also be connected to the ground plain. Loops must be made as small
as possible, in order to keep the noise coupled in via the PCB as small as possible. Also
parasitics should stay as small as possible. Values of C
x1
and C
x2
should be chosen
smaller accordingly to the increase in parasitics of the PCB layout.