Ublox SARA-R5 Series System Integration Manual

SARA-R5 series - System integration manual
UBX-19041356 - R04 Design-in Page 44 of 118
C1-Public
2.2.1.3 Guidelines for VCC supply circuit design using low drop-out linear regulator
The use of a linear regulator is suggested when the difference from the available supply rail source
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 Low Drop-Out (LDO) linear regulator connected to VCC pins should meet
the following prerequisites to comply with the module VCC requirements summarized in Table 5:
• Power capabilities: the LDO linear regulator with its output circuit must be capable of providing a
voltage value to the VCC pins within the specified operating range and must be capable of
delivering to VCC pins the maximum current consumption occurring during a transmission at the
maximum Tx power, as specified in the SARA-R5 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 rated range (i.e. check the voltage drop from the maximum
input voltage to the minimum output voltage to evaluate the power dissipation of the regulator).
Figure 23 and the components listed in Table 11 show an example of a power supply circuit for
SARA-R5 series modules, where the module VCC is supplied by an LDO linear regulator capable of
delivering maximum peak / pulse current specified for LTE use-case, with suitable power handling
capability.
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 (e.g. ~4.1 V for the VCC, as in the
circuits described in Figure 23 and Table 11). This reduces the power on the linear regulator and
improves the thermal design of the circuit.
5V
C1
R1
IN OUT
ADJ
GND
5
8
1
3
4
C2
R2
R3
U1
EN
SARA-R5 series
52
VCC
53
VCC
51
VCC
GND
C4
C3
C5 C6
Figure 23: Example of VCC supply circuit for SARA-R5 series modules, using an LDO linear regulator
Reference
Description
Part number - Manufacturer
C1
1 F capacitor ceramic X5R 6.3 V
Generic manufacturer
C2
22 F capacitor ceramic X5R 25 V
Generic manufacturer
C3
100 nF capacitor ceramic X7R 16 V
GCM155R71C104KA55 - Murata
C4
10 nF capacitor ceramic X7R 16 V
GRT155R71C103KE01 - Murata
C5
68 pF capacitor ceramic C0G 0402 5% 50 V
GRM1555C1E680JA01 - Murata
C6
15 pF capacitor ceramic C0G 0402 5% 50 V
GJM1555C1H150JB01 - Murata
R1
47 k resistor 0.1 W
Generic manufacturer
R2
41 k resistor 0.1 W
Generic manufacturer
R3
10 k resistor 0.1 W
Generic manufacturer
U1
LDO linear regulator 1.0 A
AP7361C – Diodes Incorporated
Table 11: Components for VCC supply circuit for SARA-R5 series modules, using an LDO linear regulator
☞ See the section 2.2.1.9, and in particular Figure 28 / Table 15, for the parts recommended to be
provided if the application device integrates an internal antenna.

Ublox SARA-R5 Series Specifications

General

Brand	Ublox
Model	SARA-R5 Series
Category	Control Unit
Language	English