Smart Module Series
SC262R_Series_Hardware_Design 44 / 115
USB_DP
USB_DM
USB_VBUS
1
2
3
4
5
USB_DP
USB_DM
VUSB
USB_ID
GND
G
N
D
G
N
D
G
N
D
G
N
D
6
7
8
9
100 nF
Module
C1
D1
D2
D3
ESD
ESD ESD
GND
Figure 12: USB Interface Reference Design (OTG Not Supported)
10
μF
EN
VIN
SW
NC
VOUT
VOUT
4
5
1
7
8
6
2
9
3
A
G
N
D
P
G
N
D
P
G
N
D
10K
22
μF/
10 V
1.0
μH
USB_DP
USB_DM
USB_VBUS
USB_ID
1
2
3
4
5
USB_DP
USB_DM
VUSB
USB_ID
GND
G
N
D
G
N
D
G
N
D
G
N
D
6
7
8
9
100 nF
Module
VBAT
GPIO
VBAT
C1
C2
L1
U1
R1
C3
D1
D2
D3
D4
ESD
ESD
ESD
ESD
GND
Figure 13: USB Interface Reference Design (OTG Supported)
In order to ensure USB performance, comply with the following principles when designing the USB
interface.
⚫
Route the USB signal traces as a differential pair with total grounding. The impedance of USB
differential trace should be controlled to 90
Ω.
⚫
Keep the ESD protection devices as close as possible to the USB connector. Pay attention to the
influence of junction capacitance of ESD protection devices on USB data lines. Typically, the
capacitance value should be less than 2 pF.
⚫
Do not route signal traces under crystals, oscillators, magnetic devices or RF signal traces. Route the
USB differential traces in inner-layer of the PCB, and surround the traces with ground on that layer
