lpc11u12 NXP Semiconductors, lpc11u12 Datasheet - Page 54

• Manufacturer Part Number: lpc11u12
• Description: 32-bit Arm Cortex-m0 Microcontroller; Up To 32 Kb Flash; 6 Kb Sram; Usb Device; Usart
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC11U1X
Product data sheet
11.3 XTAL Printed-Circuit Board (PCB) layout guidelines
Table 17.
Table 18.
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.
Fundamental oscillation
frequency F
5 MHz - 10 MHz
10 MHz - 15 MHz
15 MHz - 20 MHz
Fundamental oscillation
frequency F
15 MHz - 20 MHz
20 MHz - 25 MHz
Recommended values for C
components parameters) low frequency mode
Recommended values for C
components parameters) high frequency mode
OSC
OSC
All information provided in this document is subject to legal disclaimers.
Rev. 2 — 11 January 2012
Crystal load
capacitance C
10 pF
20 pF
30 pF
10 pF
20 pF
10 pF
Crystal load
capacitance C
10 pF
20 pF
10 pF
20 pF
X1
X1
/C
/C
L
L
X2
X2
in oscillation mode (crystal and external
in oscillation mode (crystal and external
Maximum crystal
series resistance R
< 300 
< 200 
< 100 
< 160 
< 60 
< 80 
Maximum crystal
series resistance R
< 180 
< 100 
< 160 
< 80 
x1
and C
32-bit ARM Cortex-M0 microcontroller
x2
should be chosen smaller
x1
S
S
, C
LPC11U1x
x2
External load
capacitors C
18 pF, 18 pF
39 pF, 39 pF
57 pF, 57 pF
18 pF, 18 pF
39 pF, 39 pF
18 pF, 18 pF
External load
capacitors C
18 pF, 18 pF
39 pF, 39 pF
18 pF, 18 pF
39 pF, 39 pF
, and C
© NXP B.V. 2012. All rights reserved.
x3
in case of
X1
X1
, C
, C
54 of 69
X2
X2