ZTE Corporation ZM8300G 用户手册
ZTE ZM8300G Module Hardware User Manual
<All rights reserved. No distribution without prior permission of ZTE.>
33
transmission, software commissioning, and software upgrade. Table 3-9 describes USB
signals.
Table 3-9 Description of USB Signals
Pin
Signal
I/O
Description
Remarks
40
USB_VBUS
I
USB PHY power detection
Only used for USB PHY
detection and not used
as a power supply
52
USB_DP
AI/O
USB differential data bus
(positive)
90
ohm
differential
impedance
53
USB_DM
AI/O
USB differential data bus
(negative)
90
ohm
differential
impedance
39
USB_ID
I
USB_ID detection signal
OTG
function;
No
connection
when
working as a device.
51
GND
GND
3.9.2
Design Points and Recommended Circuit
For detailed information about USB 2.0 specifications, access http://www.usb.org/home.
Figure 3-12 illustrates a circuit recommended for the USB interface. To ensure that
subsequent commissioning and upgrading operations can be smoothly performed, customers
need to design a USB 2.0 connector on an external system board. ZTE recommends the
following model: MOLEX: 1051330001 and LS: GU073-5P-SE-E2000. The bead in Figure
3-14 can be replaced with a resistor. If no high-speed data services are involved and the USB
differential signals are properly protected, the common mode inductor can be removed.
ZM8300
USB
Connector
1
2
3
4
5
S
1
S
2
S
3
S
4
VBUS
DM
DP
DP
ID
GND
USB_VBUS
USB_DM
USB_DP
USB_ID
Bead
1
0
0
0
p
F
4
7
K
NA
Common Mode
Noise Filter