LARA-R2 series - System Integration Manual
UBX-16010573 - R12
Design-in
Page 76 of 157
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
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.
C1
C4
GND
C3
C2
C6
LARA-R211
52
VCC
53
VCC
51
VCC
+
Li-Ion/Li-Pol
Battery
C7
SW
VIN
SHDNn
GND
FB
C8
R1
R2
L1
U1
Step-up
Regulator
D1
C9
C5
Figure 33: VCC circuit example with a separate supply for LARA-R211 modules
Reference
Description
Part Number - Manufacturer
C1
330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m
T520D337M006ATE045 - KEMET
C2
10 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C103KA01 - Murata
C3
100 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R61A104KA01 - Murata
C4
68 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H680JA01 - Murata
C5
15 pF Capacitor Ceramic C0G 0402 5% 25 V
GRM1555C1E150JA01 - Murata
C6
8.2 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H8R2DZ01 - Murata
C7
10 µF Capacitor Ceramic X5R 0603 20% 6.3 V
GRM188R60J106ME47 - Murata
C8
22 µF Capacitor Ceramic X5R 1210 10% 25 V
GRM32ER61E226KE15 - Murata
C9
10 pF Capacitor Ceramic C0G 0402 5% 25 V
GRM1555C1E100JA01 - Murata
D1
Schottky Diode 40 V 1 A
SS14 - Vishay General Semiconductor
L1
10 µH Inductor 20% 1 A 276 m
SRN3015-100M - Bourns Inc.
R1
1 M
Resistor 0402 5% 0.063 W
RC0402FR-071ML - Yageo Phycomp
R2
412 k
Resistor 0402 5% 0.063 W
RC0402FR-07412KL - Yageo Phycomp
U1
Step-up Regulator 350 mA
AP3015 - Diodes Incorporated
Table 25: Example of components for VCC circuit with a separate supply for LARA-R211 modules