LPC2917/01 NXP [NXP Semiconductors], LPC2917/01 Datasheet - Page 77

• Manufacturer Part Number: LPC2917/01
• Description: ARM9 microcontroller with CAN and LIN
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
LPC2917_19_01_2
Preliminary data sheet
10.3 XIN_OSC input
10.4 XIN_OSC Printed Circuit Board (PCB) layout guidelines
The input voltage to the on-chip oscillators is limited to 1.8 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
manual UM10316 .
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
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
smaller accordingly to the increase in parasitics of the PCB layout.
Fig 33. Slave mode operation of the on-chip oscillator
i
= 100 pF. To limit the input voltage to the specified range, choose an additional
g
which attenuates the input voltage by a factor C
Rev. 02 — 17 June 2009
rms
is needed. For more details see the LPC29xx User
LPC2917/01; LPC2919/01
XIN_OSC
LPC29xx
C i
100 pF
ARM9 microcontroller with CAN and LIN
002aae730
C g
x1
and C
x2
x1
should be chosen
and C
i
/(C
© NXP B.V. 2009. All rights reserved.
x2
i
, and C
+ C
g
). In slave
x3
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in