Datasheet

LPC11E6X 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 — 21 May 2014 72 of 89
NXP Semiconductors
LPC11E6x
32-bit ARM Cortex-M0+ microcontroller
[3] WatchDog oscillator disabled, Brown-Out Detect (BOD) disabled.
[4] Wake-up from deep power-down causes the part to go through entire reset process. The wake-up time
measured is the time between when a wake-up pin is triggered to wake up the device from the low-power
modes and when a GPIO output pin is set in the reset handler.
14.3 XTAL input and crystal oscillator component selection
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
i
= 100 pF. To limit the input voltage to the specified range, choose an additional
capacitor to ground C
g
which attenuates the input voltage by a factor C
i
/(C
i
+ C
g
). In slave
mode, a minimum of 200 mV(RMS) is needed.
In slave mode the input clock signal should be coupled through a capacitor of 100 pF
(Figure 38
), with an amplitude between 200 mV (RMS) and 1000 mV (RMS). This
corresponds to a square wave signal with a signal swing of between 280 mV and 1.4 V.
The XTALOUT pin in this configuration can be left unconnected.
External components and models used in oscillation mode are shown in Figure 39
and in
Table 26
and Table 27. Since the feedback resistance is integrated on chip, only a crystal
and the capacitances C
X1
and C
X2
must be connected externally in case of fundamental
mode oscillation (the fundamental frequency is represented by L, C
L
and R
S
).
Capacitance C
P
in Figure 39 represents the parallel package capacitance and should not
be larger than 7 pF. Parameters F
OSC
, C
L
, R
S
and C
P
are supplied by the crystal
manufacturer (see Table 26
).
Fig 38. Slave mode operation of the on-chip oscillator
LPC1xxx
XTALIN
C
i
100 pF
C
g
002aae788