LISA-C2 series and FW75-C200 - System Integration Manual
UBX-13000620 - R21
Early Production Information
System description
Page 33 of 103
Figure 17: Current consumption profile during cyclic idle/active mode (power saving disabled)
1.9.3.2
USB application circuit
Since the module acts as a USB device, the USB supply (5.0 V typ.) must be provided to
VUSB_DET
by the
connected USB host. The USB interface is enabled only when a valid voltage as USB supply is detected by the
VUSB_DET
input. Neither the USB interface, nor the whole module is supplied by the
VUSB_DET
input: the
VUSB_DET
senses the USB supply voltage and absorbs few microamperes.
The
USB_D+
and
USB_D-
lines carry the USB serial data and signaling. The lines are used in single ended mode
for relatively low speed signaling handshake, as well as in differential mode for fast signaling and data transfer.
USB pull-up or pull-down resistors on pins
USB_D+
and
USB_D-
as required by the
Universal Serial Bus Revision
2.0 specification
[10] are part of the USB pad driver and do not need to be externally provided.
External series resistors on pins
USB_D+
and
USB_D-
as required by the
Universal Serial Bus Revision 2.0
[10] are also integrated: characteristic impedance of
USB_D+
and
USB_D-
lines is specified by the
USB standard. The most important parameter is the differential characteristic impedance applicable for
odd-mode electromagnetic field, which should be as close as possible to 90
Ω
differential, signal integrity may
be degraded if the PCB layout is not optimal, especially when the USB signaling lines are very long.
u-blox C200
VBUS
D+
D-
GND
VUSB_DET
USB_D+
USB_D-
GND
C
1
USB DEVICE
CONNECTO
R
D
1
D
2
D
3
Figure 18: USB Interface application circuit
Reference
Description
Part Number - Manufacturer
D1, D2, D3
Very Low Capacitance ESD Protection
PESD0402-140 - Tyco Electronics
C2
100 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R61A104KA01 - Murata
Table 16: Component for USB application circuit
~15 mA
IDLE MODE
0.98s / 2.26s / 4.82 s
(EX enabled)
~300ms
Time [s]
Current [mA]
50
0
Active Mode
60-70 mA
