Datasheet

DRAFT DRAFT DRAFT DR DRAFT DRAFT DRAFT
D
RAF
DRAFT DRAFT DRA
F
T D
RAFT DR
AFT D
DRA
F
T DRAFT DRAFT
D
RAFT
DRAFT
D
RAFT
DRA
LPC15xx All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
Objective data sheet Rev. 1.0 — 16 January 2014 87 of 98
NXP Semiconductors
LPC15xx
32-bit ARM Cortex-M3 microcontroller
Select C
x1
and C
x2
based on the external 32 kHz crystal used in the application
circuitry.The pad capacitance C
P
of the RTCXIN and RTCXOUT pad is 3 pF. If the external
crystal’s load capacitance is C
L
, the optimal C
x1
and C
x2
can be selected as:
C
x1
= C
x2
= 2 x C
L
– C
P