Datasheet

LPC11U6x All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 1.2 — 26 May 2014 80 of 96
NXP Semiconductors
LPC11U6x
32-bit ARM Cortex-M0+ microcontroller
14.5 XTAL 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
, 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 plane. Loops must be made as small as possible to
keep the noise coupled in via the PCB as small as possible. Also parasitics should stay as
small as possible. Smaller values of C
x1
and C
x2
should be chosen according to the
increase in parasitics of the PCB layout.