LPC2131_32_34_36_38 NXP Semiconductors, LPC2131_32_34_36_38 Datasheet - Page 36

• Manufacturer Part Number: LPC2131_32_34_36_38
• Description: The LPC2131/32/34/36/38 microcontrollers are based on a 16/32-bit ARM7TDMI-S CPUwith real-time emulation and embedded trace support, that combine the microcontrollerwith 32 kB, 64 kB, 128 kB, 256 kB and 512 kB of embedded high-speed flash memory
• Manufacturer: NXP Semiconductors

NXP Semiconductors
12. Application information
LPC2131_32_34_36_38
Product data sheet
12.1 Crystal oscillator XTAL input and 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
capacitor to ground C
slave mode, a minimum of 200 mV (RMS) is needed.
In slave mode the input clock signal should be coupled by means of a capacitor of 100 pF
(Figure
corresponds to a square wave signal with a signal swing of between 280 mV and 1.4 V.
The XTAL2 pin in this configuration can be left unconnected.
External components and models used in oscillation mode are shown in
Table 10
and the capacitances C
fundamental mode oscillation (the fundamental frequency is represented by L, C
R
not be larger than 7 pF. Parameters F
manufacturer.
Fig 13. Slave mode operation of the on-chip oscillator
i
S
= 100 pF. To limit the input voltage to the specified range, choose an additional
). Capacitance C
13), with an amplitude between 200 mV (RMS) and 1000 mV (RMS). This
and
Table
All information provided in this document is subject to legal disclaimers.
P
11. Since the feedback resistance is integrated on chip, only a crystal
in
g
which attenuates the input voltage by a factor C
Figure 14
Rev. 5.1 — 29 July 2011
X1
and C
X2
represents the parallel package capacitance and should
need to be connected externally in case of
OSC
XTAL1
C i
100 pF
LPC2xxx
, C
L
, R
LPC2131/32/34/36/38
S
002aae718
Single-chip 16/32-bit microcontrollers
C g
and C
P
are supplied by the crystal
i
© NXP B.V. 2011. All rights reserved.
/ (C
Figure 14
i
+ C
g
L
). In
and
and in
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