Integration Manual

LISA-U2 series - System Integration Manual
UBX-13001118 - R25 System description Page 26 of 182
 68 pF capacitor with Self-Resonant Frequency in the 800/900 MHz range (e.g. Murata
GRM1555C1H680J) at the VCC line where it narrows close to the module (see Figure 9), to filter
EMI in lower bands
 15 pF capacitor with Self-Resonant Frequency in 1800/1900 MHz range (e.g. Murata
GRM1555C1H150J)
at the VCC line where it narrows close to the module (see Figure 9), to filter EMI in higher bands
 10 nF capacitor (e.g. Murata GRM155R71C103K) to filter digital logic noise from clocks and data
sources
 100 nF capacitor (e.g. Murata GRM155R61A104K) to filter digital logic noise from clocks and data
sources
☞ Figure 9 shows the complete configuration, but keep in mind that the mounting of each single
component depends on the application design. It is highly recommended to provide the series
ferrite bead and all the VCC bypass capacitors as described in Figure 9 and Table 10 if the
application device integrates an internal antenna.
C1
GND
C2 C4
LISA-U2 series
62
VCC
63
VCC
61
VCC
3V8
C5
+
LISA-U
series
C5
GND plane
VCC line
Capacitor with
SRF ~900 MHz
FB1
C1 C3 C4
FB1
Ferrite Bead
for GHz noise
C2
C3
Capacitor with
SRF ~1900 MHz
Figure 9: Suggested schematic and layout design for the VCC line; highly recommended when using an integrated antenna
Reference
Description
Part Number - Manufacturer
C1
68 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H680JA01 - Murata
C2
15 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H150JA01 - Murata
C3
10 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C103KA01 - Murata
C4
100 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C104KA01 - Murata
C5
330 µ F Capacitor Tantalum D_SIZE 6.3 V 45 m
T520D337M006ATE045 - KEMET
FB1
Chip Ferrite Bead EMI Filter for GHz Band Noise
220  at 100 MHz, 260  at 1 GHz, 2000 mA
BLM18EG221SN1 - Murata
Table 10: Suggested parts for VCC circuit close to module’ pins; highly recommended when using an integrated antenna
External battery charging application circuit
LISA-U2 series modules do not have an on-board charging circuit. An example of a battery charger
design, suitable for applications that are battery powered with a Li-Ion (or Li-Polymer) cell, is provided
in Figure 10.
In the application circuit, a rechargeable Li-Ion (or Li-Polymer) battery cell, that features proper pulse
and DC discharge current capabilities and proper DC series resistance, is directly connected to the
VCC supply input of LISA-U2 series module. Battery charging is completely managed by the
STMicroelectronics L6924U Battery Charger IC that, from a USB power source (5.0 V typ.), charges
as a linear charger the battery, in three phases:
 Pre-charge constant current (active when the battery is deeply discharged): the battery is
charged with a low current, set to 10% of the fast-charge current.