LEXI-R422 - System integration manual
UBX-23007449 - R02
Design-in
Page 76 of 108
C1-Public
The LEXI-R422 modules do not support AT command / data communication over USB interface: the
USB interface is available on these modules product versions for FW upgrade by means of the
dedicated u-blox EasyFlash tool and for diagnostic purposes only. Therefore, the USB interface of
these modules product versions is not designed to be connected to an external host processor
mounted on the application board.
☞
It is highly recommended to provide access to
V_INT
,
PWR_CTRL
,
USB_5V0
,
USB_3V3
,
USB_D+
,
USB_D-
, and
RSVD #99
pins for FW upgrade and/or for diagnostic purpose, making available:
(a)
accessible test points, directly connected to the related pins of the module, as illustrated in
the application circuit example of
, or
(b)
the specific SAMTEC FTSH-103-01-L-DV male header connector, directly connected to the
related pins of the module, as shown in the application circuit example of
, or
(c)
a generic USB device connector, connected to the related pins of the module through the
specific circuit illustrated in the application circuit example of
R9
USB_D+
R8
USB_D-
GND
LEXI-R422
R7
USB_3V3
R10
USB_5V0
J5
RSVD (#99)
Test-Point
A11
V_INT
D+
D-
GND
USB DEVICE
CONNECTOR
VBUS
D1
D2
D3
VIN
VOUT
LDO regulator
Enable
U1
C2
R1
GND
C1
U2
R9
USB_D+
R8
USB_D-
GND
LEXI-R422
R7
USB_3V3
Test-Point
Test-Point
Test-Point
R10
USB_5V0
Test-Point
J5
RSVD (#99)
Test-Point
A11
V_INT
Test-Point
R9
USB_D+
R8
USB_D-
GND
LEXI-R422
R7
USB_3V3
R10
USB_5V0
J5
RSVD (#99)
Test-Point
A11
V_INT
GND
USB_D-
USB_5V0
USB_3V3
USB_D+
V_INT
SAMTEC
FTSH-103-01-L-DV
male header connector
Top view
(a)
(b)
(c)
Figure 56: USB Interface application circuits for LEXI-R422 modules
Reference
Description
Part number - Manufacturer
C1, C2
1 µF capacitor ceramic X7R 16 V
Generic manufacturer
D1, D2, D3
Very low capacitance ESD protection
PESD0402-140 - Littelfuse
R1
10 k
resistor 0402 5% 0.1 W
Generic manufacturer
U1
LDO linear regulator 3.3 V 150 mA
NCP600SN330T1G - ON Semiconductor
U2
NPN/PNP 10k/47k biased silicon transistor
BCR35PN - Infineon Technologies
Table 35: Components for USB application circuits for LEXI-R422 modules