User's Manual

SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R18 Advance Information Design-in
Page 102 of 206
C9 C12
GND
C11C10 C13
SARA-G3 / SARA-U2
52
VCC
53
VCC
51
VCC
+
Primary
Source
R3
U1
EN
ILIM
ISET
TMR
AGND
VIN
C2C1
12V
NTC
PGND
SW
SYS
BAT
C4
R1
R2
D1
θ
Li-Ion/Li-Pol
Battery Pack
B1
C5
Li-Ion/Li-Polymer Battery
Charger / Regulator with
Power Path Managment
VCC
C3 C6
L1
BST
D2
VLIM
R4
R5
C7 C8
Ferrite Bead
or 0Ω
Figure 49: Li-Ion (or Li-Polymer) battery charging and power path management application circuit
Reference Description Part Number - Manufacturer
B1
Li-Ion (or Li-Polymer) battery pack with 10 k: NTC
Various manufacturer
C1, C5, C6
22 μF Capacitor Ceramic X5R 1210 10% 25 V
GRM32ER61E226KE15 - Murata
C2, C4, C10
100 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R61A104KA01 - Murata
C3
1 μF Capacitor Ceramic X7R 0603 10% 25 V
GRM188R71E105KA12 - Murata
C7, C12
56 pF Capacitor Ceramic C0G 0402 5% 25 V
GRM1555C1E560JA01 - Murata
C8, C13
15 pF Capacitor Ceramic C0G 0402 5% 25 V
GRM1555C1E150JA01 - Murata
C9
330 μF Capacitor Tantalum D_SIZE 6.3 V 45 m:
T520D337M006ATE045 - KEMET
C11
10 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C103KA01 - Murata
D1, D2
Low Capacitance ESD Protection
CG0402MLE-18G - Bourns
R1, R3, R5
10 k: Resistor 0402 5% 1/16 W
RC0402JR-0710KL - Yageo Phycomp
R2
1.0 k: Resistor 0402 5% 0.1 W
RC0402JR-071K0L - Yageo Phycomp
R4
22 k: Resistor 0402 5% 1/16 W
RC0402JR-0722KL - Yageo Phycomp
L1
1.2 μH Inductor 6 A 21 m: 20%
7447745012 - Wurth
U1
Li-Ion/Li-Polymer Battery DC/DC Charger / Regulator
with integrated Power Path Management function
MP2617 - Monolithic Power Systems (MPS)
Table 30: Suggested components for Li-Ion (or Li-Polymer) battery charging and power path management application circuit
2.2.1.10 Guidelines for VCC supply layout design
Good connection of the module VCC pins with DC supply source is required for correct RF performance.
Guidelines are summarized in the following list:
x All the available VCC pins must be connected to the DC source.
x VCC connection must be as wide as possible and as short as possible.
x Any series component with Equivalent Series Resistance (ESR) greater than few milliohms must be avoided.
x VCC connection must be routed through a PCB area separated from sensitive analog signals and sensitive
functional units: it is good practice to interpose at least one layer of PCB ground between VCC track and
other signal routing.
x Coupling between VCC and audio lines (especially microphone inputs) must be avoided, because the typical
GSM burst has a periodic nature of approx. 217 Hz, which lies in the audible audio range.
x The tank bypass capacitor with low ESR for current spikes smoothing described in Figure 44 and Table 27
should be placed close to the VCC pins. If the main DC source is a switching DC-DC converter, place the
large capacitor close to the DC-DC output and minimize the VCC track length. Otherwise consider using
separate capacitors for DC-DC converter and cellular module tank capacitor.