lpc4310 NXP Semiconductors, lpc4310 Datasheet - Page 77

• Manufacturer Part Number: lpc4310
• Description: Lpc4350/30/20/10 32-bit Arm Cortex-m4/m0 Mcu; Up To 264 Kb Sram; Ethernet; Two High-speed Usbs; Advanced Configurable Peripherals
• Manufacturer: NXP Semiconductors

NXP Semiconductors
13. Application information
LPC4350_30_20_10
Objective data sheet
13.1 XTAL1 input
13.2 XTAL Printed Circuit Board (PCB) layout guidelines
The input voltage to the on-chip oscillators is limited to 1.2 V. If the oscillator is driven by a
clock in slave mode, it is recommended that the input be coupled through a capacitor with
C
capacitor to ground C
mode, a minimum of 200 mV (RMS) is needed.
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
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
accordingly to the increase in parasitics of the PCB layout.
Fig 28. Slave mode operation of the on-chip oscillator
i
= 100 pF. To limit the input voltage to the specified range, choose an additional
All information provided in this document is subject to legal disclaimers.
g
Rev. 1 — 29 October 2010
which attenuates the input voltage by a factor C
XTAL1
LPC4xxx
C i
100 pF
32-bit ARM Cortex-M4/M0 microcontroller
x1
and C
002aaf874
C g
LPC4350/30/20/10
x2
should be chosen smaller
x1
, C
x2
, and C
i
/(C
© NXP B.V. 2010. All rights reserved.
i
+ C
x3
g
). In slave
in case of
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