LPC2141_42_44_46_48 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 5 — 12 August 2011 36 of 45
NXP Semiconductors
LPC2141/42/44/46/48
Single-chip 16-bit/32-bit microcontrollers
12. Application information
12.1 Suggested USB interface solutions
12.2 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
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.
Fig 10. LPC2141/42/44/46/48 USB interface using the CONNECT function on pin 17
LPC2141/42/
44/46/48
USB-B
connector
D+
CONNECT
soft-connect switch
D−
VBUS
V
SS
V
DD
R1
1.5 kΩ
R
S
= 33 Ω
002aab563
R
S
= 33 Ω
Fig 11. LPC2141/42/44/46/48 USB interface using the UP_LED function on pin 17
LPC2141/42/
44/46/48
V
DD
R1
1.5 kΩ
R2
UP_LED
002aab562
USB-B
connector
D+
D−
VBUS
V
SS
R
S
= 33 Ω
R
S
= 33 Ω
