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2.2.1.7 Additional guidelines for VCC supply circuit design of LARA-R211 modules
LARA-R211 modules provide separate supply inputs over the VCC pins (see Figure 3):

VCC pins #52 and #53 represent the supply input for the internal RF power amplifier, demanding most of the
total current drawn of the module when RF transmission is enabled during a voice/data call

VCC pin #51 represents the supply input for the internal baseband Power Management Unit and the internal
transceiver, demanding a minor part of the total current drawn of the module when RF transmission is enabled
during a voice/data call
LARA-R211 modules support two different extended operating voltage ranges: one for the VCC pins #52 and #53,
and another one for the VCC pin #51 (see the LARA-R2 series Data Sheet [1]).
All the VCC pins are in general intended to be connected to the same external power supply circuit, but separate
supply sources can be implemented for specific (e.g. battery-powered) applications considering that the voltage at
the VCC pins #52 and #53 can drop to a value lower than the one at the VCC pin #51, keeping the module still
switched-on and functional. Figure 33 describes a possible application circuit.
Li-Ion/Li-Pol
Battery
Figure 33: VCC circuit example with a separate supply for LARA-R211 modules
Reference Description
C1
330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m
C2 10 nF Capacitor Ceramic X7R 0402 10% 16 V
C3 100 nF Capacitor Ceramic X7R 0402 10% 16 V
C4 68 pF Capacitor Ceramic C0G 0402 5% 50 V
C5 15 pF Capacitor Ceramic C0G 0402 5% 25 V
C6 8.2 pF Capacitor Ceramic C0G 0402 5% 50 V
C7 10 µF Capacitor Ceramic X5R 0603 20% 6.3 V
C8 22 µF Capacitor Ceramic X5R 1210 10% 25 V
C9 10 pF Capacitor Ceramic C0G 0402 5% 25 V
D1 Schottky Diode 40 V 1 A
L1
10 µH Inductor 20% 1 A 276 m
R1 1 M Resistor 0402 5% 0.063 W
R2
412 k Resistor 0402 5% 0.063 W
U1 Step-up Regulator 350 mA
Table 25: Example of components for VCC circuit with a separate supply for LARA-R211 modules
UBX-16010573 - R12
L1 D1
Step-up
Regulator
VIN SW
SHDNn
FB
C7
GND
U1
+
C1 C2
LARA-R2 series - System Integration Manual
VCC
51
R1
C9
C8
R2
VCC
52
VCC
53
C3 C4 C5 C6
GND
Part Number - Manufacturer
T520D337M006ATE045 - KEMET
GRM155R71C103KA01 - Murata
GRM155R61A104KA01 - Murata
GRM1555C1H680JA01 - Murata
GRM1555C1E150JA01 - Murata
GRM1555C1H8R2DZ01 - Murata
GRM188R60J106ME47 - Murata
GRM32ER61E226KE15 - Murata
GRM1555C1E100JA01 - Murata
SS14 - Vishay General Semiconductor
SRN3015-100M - Bourns Inc.
RC0402FR-071ML - Yageo Phycomp
RC0402FR-07412KL - Yageo Phycomp
AP3015 - Diodes Incorporated
LARA-R211
Design-in
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