LENA-R8 series - System integration manual
UBX-22015376 - R02
Design-in
Page 43 of 116
C1-Public
Additional parts described in
are recommended to be provided near the
VCC
pins of the module for various RF and/or EMI improvements purposes.
For modules supporting 2G or LTE TDD, to avoid voltage drop undershoot and overshoot at the start
and end of a transmit burst and mitigate possible RF spurious emission, place a bypass capacitor with
large capacitance (at least 100
µ
F) and low ESR near the
VCC
pins, for example:
•
330
µ
F capacitance, 45 m
ESR (e.g., KEMET T520D337M006ATE045, Tantalum Capacitor)
To reduce voltage ripple and noise, improving RF performance especially if the application device
integrates an internal antenna, place the following bypass capacitors near the
VCC
pins, narrowing
the
VCC
line down to the pad of the capacitors, to improve the RF noise rejection in the band centered
on the Self-Resonant Frequency of the capacitors:
•
82 pF 0402 ceramic capacitor with Self-Resonant Frequency in the 800/900 MHz range
•
15 pF 0402 ceramic capacitor with Self-Resonant Frequency in the 1800/1900 MHz range
•
8.2 pF 0402 ceramic capacitor with Self-Resonant Frequency in the 2500/2600 MHz range
•
10 nF 0402 ceramic capacitor, to filter digital logic noise from clocks and data sources
•
100 nF 0402 ceramic capacitor, to filter digital logic noise from clocks and data sources
An additional series ferrite bead can be properly placed on the
VCC
line for additional RF noise filtering,
in particular if the application device integrates an internal antenna:
•
Ferrite bead specifically designed for EMI / noise suppression in the ~GHz band (as the Murata
BLM18EG221SN1), placed as close as possible to the
VCC
pins of the module, implementing the
circuit described in
, to filter out EMI in all the cellular bands
C2
GND
C3
C4
LENA-R8 series
52
VCC
53
VCC
51
VCC
C1
C6
3V8
+
C5
FB1
Recommended for
possible VCC EMI
suppression
(0R otherwise)
Figure 25: Suggested schematic for the VCC bypass capacitors to reduce ripple / noise on the supply voltage profile
Reference
Description
Part number - manufacturer
C1
8.2 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H8R2DZ01 - Murata
C2
15 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H150JA01 - Murata
C3
82 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H820JA01 - Murata
C4
10 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C103KA01 - Murata
C5
100 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C104KA01 - Murata
C6
330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m
T520D337M006ATE045 - KEMET
10
µ
F Capacitor Ceramic X5R 0603 20% 6.3 V
GRM188R60J106ME47 - Murata
FB1
Chip Ferrite Bead EMI Filter for GHz Band Noise
220
at 100 MHz, 260
at 1 GHz, 2000 mA
BLM18EG221SN1 - Murata
Table 14: Suggested components to reduce ripple / noise on VCC
☞
The necessity of each part depends on the specific design, but it is recommended to provide all
the bypass capacitors described in
, and consider a ferrite bead designed for
EMI suppression in the ~GHz band, if the application device integrates an internal antenna.
