Usb Interface - Quectel EC25 series User Manual

criteria belo ow in the US SIM circuit de
 Keep la ayout of USI
200mm m.
 Keep U USIM card si
Assure the ground

ground and USIM_
 To avo id cross-talk
shield t them with su
 In orde er to offer go
should not be more
and th e USIM ca ard so as to
protect ion. The 33 3pFcapacitor
USIM p peripheral ci
 The pu ll-up resisto or on USIM_
and sen nsitive occa
3.10. US SB Interfa
EC25 conta ains one inte
specification n and suppo
used for AT T command,
upgrade. Th he following
Table 10: U USB Pin Des
Pin Name Pin No o.
USB_DP 69
USB_DM 70
USB_VBU US 71
GND 72
More details s about the
The USB in nterface is re
figure show ws the refere
esign:
IM card as c close as pos
ignal away f from RF and
between th he module a
_VDD no les ss than 0.5m
k between USIM_DATA
urrounded g round.
ood ESD pr rotection, it
e than 50pF F. The 22oh
o suppress
rs are used
rcuit should be close to
_DATA line c
sion areapp plied, and sh
ace
egrated Univ versal Seria
orts high-sp eed (480Mb
data transm mission, GNS
table shows s the pin def
scription
I/O Desc
IO USB d
IO USB d
Used
PI
conne
Groun
USB 2.0 spe ecifications,
ecommende ed to be res
nce circuit o of USB interf
E EC25-A_Us ser_ManualC
ssible to the module. As
d VBAT align nment.
and the USIM M connecto
mm to mainta ain the same
A and USIM M_CLK, kee
is recomme ended to ad
mresistors s should be ad
the EMI s spurious tra
for filtering interferenc
the USIM c connector.
can improve anti-jammin
hould be plac ced close to
al Bus (USB ) transceive
bps) and ful l-speed (12M
SS NMEA s sentences ou
finition of US SB interface
ription
differential d data bus (po
differential d data bus (mi
for detectin g the USB
ection.
nd
please visit t http://www.
served for fi rmware upg
face.
Confidentia al / Release
EC25-AU
ssure the len ngth of trace
r short and wide. Keep
e electric po otential.
p them awa ay with eac
d TVS whic ch parasitic
dded in seri ies between
ansmission a and enhanc
ce of GSM90 00.Please n
ng capability y when long
o the USIM c connector.
er which com mplies with t
Mbps)mode es. The USB
utput, softwa are debug a
e.
Comment
Require dif
ositive).
impedance
Require dif
inus).
impedance
Typical 5.0
.usb.org/hom me.
grade in you ur design. T
d 34 / 6 69
L LTE Module e
ser Manua al
e is less than n
the width o of
ch other and d
capacitance e
n the module e
ce the ESD D
note that the e
layout trace e
the USB 2.0 0
B interface is s
and firmware e
fferential
e of 90Ω.
fferential
e of 90Ω.
0V
The following g