Datasheet

LPC2131_32_34_36_38 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 5.1 — 29 July 2011 37 of 45
NXP Semiconductors
LPC2131/32/34/36/38
Single-chip 16/32-bit microcontrollers
Fig 14. Oscillator modes and models: oscillation mode of operation and external crystal
model used for C
X1
/C
X2
evaluation
Table 10. Recommended values for C
X1
/C
X2
in oscillation mode (crystal and external
components parameters): low frequency mode
Fundamental oscillation
frequency F
OSC
Crystal load
capacitance C
L
Maximum crystal
series resistance R
S
External load
capacitors C
X1
/C
X2
1 MHz to 5 MHz 10 pF < 300  18 pF, 18 pF
20 pF < 300  39 pF, 39 pF
30 pF < 300  57 pF, 57 pF
5 MHz to 10 MHz 10 pF < 300  18 pF, 18 pF
20 pF < 200  39 pF, 39 pF
30 pF < 100  57 pF, 57 pF
10 MHz to 15 MHz 10 pF < 160  18 pF, 18 pF
20 pF < 60  39 pF, 39 pF
15 MHz to 20 MHz 10 pF < 80  18 pF, 18 pF
Table 11. Recommended values for C
X1
/C
X2
in oscillation mode (crystal and external
components parameters): high frequency mode
Fundamental oscillation
frequency F
OSC
Crystal load
capacitance C
L
Maximum crystal
series resistance R
S
External load
capacitors C
X1
,
CX2
15 MHz to 20 MHz 10 pF < 180  18 pF, 18 pF
20 pF < 100  39 pF, 39 pF
20 MHz to 25 MHz 10 pF < 160  18 pF, 18 pF
20 pF < 80  39 pF, 39 pF
002aag469
LPC2xxx
XTAL1 XTAL2
C
X2
C
X1
XTAL
=
C
L
C
P
R
S
L