Ublox SARA-N210, Руководство по системной интеграции

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SARA-N2 series - System Integration Manual
UBX-17005143 - R06 Design-in Page 28 of 82
2.2.1.5 Guidelines for VCC supply circuit design using an LDO linear regulator
The use of a linear regulator is suggested when the difference from the available supply rail and the
VCC value is low: linear regulators provide high efficiency when transforming a 5 V supply to a voltage
value within the module VCC normal operating range.
The characteristics of the LDO linear regulator connected to the VCC pins should meet the following
prerequisites to comply with the module VCC requirements summarized in
Table 6 :

Power capabilities: the LDO linear regulator with its output circuit must be capable of providing a
proper voltage value to the VCC pins and of delivering to VCC pins the specified maximum average
current during a transmission at maximum power (see the SARA-N2 series Data Sheet
[1] )
 Power dissipation: the power handling capability of the LDO linear regulator must be checked to
limit its junction temperature to the maximum rated operating range (i.e. check the voltage drop
from the max input voltage to the min output voltage to evaluate the power dissipation of the
regulator)
Figure 12 and the components listed in Table 12 show a power supply circuit example, where the VCC
module supply is provided by an LDO linear regulator capable of delivering the specified current.
It is recommended to configure the LDO linear regulator to generate a voltage supply value slightly
below the maximum limit of the module VCC normal operating range. This reduces the power on the
linear regulator and improves the whole thermal design of the supply circuit.
5V
C1
IN OUT
ADJ
GND
1
2 4
5
3
C2
R1
R2
U1
EN
SARA-N2
52
VCC
53
VCC
51
VCC
GND
3V6
C3
C4
C5
Figure 12: Suggested schematic design for the VCC voltage supply application circuit using an LDO linear regulator
Reference Description Part Number - Manufacturer
C1 10
µ
F Capacitor Ceramic X5R 0603 20% 6.3 V GRM188R60J106ME47 - Murata
C2
100
µ
F Capacitor Tantalum B_SIZE 20% 6.3V 15m
 T520B107M006ATE015 - Kemet
R1
29.4 k  Resistor 0402 5% 0.1 W
RC0402FR-0729K4L - Yageo Phycomp
R2
4.7 k  Resistor 0402 5% 0.1 W
RC0402JR-074K7L - Yageo Phycomp
U1 LDO Linear Regulator ADJ 800 mA LP38511TJ-ADJ/NOPB - Texas Instrument
C3 100 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C104KA01 - Murata
C4 10 nF Capacitor Ceramic X7R 0402 10% 16 V GRM155R71C103KA01 - Murata
C5 56 pF Capacitor Ceramic C0G 0402 5% 25 V GRM1555C1E560JA01 - Murata
Table 12: Suggested components for VCC voltage supply application circuit using an LDO linear regulator