Integration Manual
Table Of Contents
- Document information
- Contents
- 1 System description
- 1.1 Overview
- 1.2 Architecture
- 1.3 Pin-out
- 1.4 Operating modes
- 1.5 Supply interfaces
- 1.5.1 Module supply input (VCC)
- 1.5.1.1 VCC supply requirements
- 1.5.1.2 VCC current consumption in LTE connected mode
- 1.5.1.3 VCC consumption in deep-sleep mode (low power mode and PSM enabled)
- 1.5.1.4 VCC current consumption in low power idle mode (low power mode enabled)
- 1.5.1.5 VCC current consumption in active mode (low power mode and PSM disabled)
- 1.5.2 Generic digital interfaces supply output (V_INT)
- 1.5.1 Module supply input (VCC)
- 1.6 System function interfaces
- 1.7 Antenna interfaces
- 1.8 SIM interface
- 1.9 Data communication interfaces
- 1.10 Audio
- 1.11 General purpose input / output (GPIO)
- 1.12 Reserved pin (RSVD)
- 2 Design-in
- 2.1 Overview
- 2.2 Supply interfaces
- 2.2.1 Module supply (VCC)
- 2.2.1.1 General guidelines for VCC supply circuit selection and design
- 2.2.1.2 Guidelines for VCC supply circuit design using a switching regulator
- 2.2.1.3 Guidelines for VCC supply circuit design using low drop-out linear regulator
- 2.2.1.4 Guidelines for VCC supply circuit design using a rechargeable battery
- 2.2.1.5 Guidelines for VCC supply circuit design using a primary battery
- 2.2.1.6 Guidelines for external battery charging circuit
- 2.2.1.7 Guidelines for external charging and power path management circuit
- 2.2.1.8 Guidelines for removing VCC supply
- 2.2.1.9 Additional guidelines for VCC supply circuit design
- 2.2.1.10 Guidelines for VCC supply layout design
- 2.2.1.11 Guidelines for grounding layout design
- 2.2.2 Generic digital interfaces supply output (V_INT)
- 2.2.1 Module supply (VCC)
- 2.3 System functions interfaces
- 2.4 Antenna interfaces
- 2.5 SIM interface
- 2.6 Data communication interfaces
- 2.6.1 UART interfaces
- 2.6.1.1 Guidelines for UART circuit design
- Providing 1 UART with the full RS-232 functionality (using the complete V.24 link)
- Providing 1 UART with the TXD, RXD, RTS, CTS, DTR and RI lines only
- Providing 1 UART with the TXD, RXD, RTS and CTS lines only
- Providing 2 UARTs with the TXD, RXD, RTS and CTS lines only
- Providing 1 UART with the TXD and RXD lines only
- Providing 2 UARTs with the TXD and RXD lines only
- Additional considerations
- 2.6.1.2 Guidelines for UART layout design
- 2.6.1.1 Guidelines for UART circuit design
- 2.6.2 USB interface
- 2.6.3 SPI interfaces
- 2.6.4 SDIO interface
- 2.6.5 DDC (I2C) interface
- 2.6.1 UART interfaces
- 2.7 Audio
- 2.8 General purpose input / output (GPIO)
- 2.9 Reserved pin (RSVD)
- 2.10 Module placement
- 2.11 Module footprint and paste mask
- 2.12 Schematic for SARA-R5 series module integration
- 2.13 Design-in checklist
- 3 Handling and soldering
- 4 Approvals
- 5 Product testing
- Appendix
- A Migration between SARA modules
- B Glossary
- Related documents
- Revision history
- Contact
SARA-R5 series - System integration manual
UBX-19041356 - R03 Design-in Page 42 of 123
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2.2.1.5 Guidelines for VCC supply circuit design using a primary battery
The characteristics of a primary (non-rechargeable) battery connected to VCC pins should meet the
following prerequisites to comply with the module VCC requirements summarized in Table 5:
Maximum pulse and DC discharge current: the non-rechargeable battery with its related output
circuit connected to the VCC pins must be capable of delivering the maximum current
consumption occurring during a transmission at maximum Tx power, as specified in SARA-R5
series data sheet [1]. The maximum discharge current is not always reported in the data sheets of
batteries, but the maximum DC discharge current is typically almost equal to the battery capacity
in Amp-hours divided by 1 hour.
DC series resistance: the non-rechargeable battery with its output circuit must be capable of
avoiding a VCC voltage drop below the operating range summarized in Table 5 during
transmission.
2.2.1.6 Guidelines for external battery charging circuit
SARA-R5 series modules do not have an on-board charging circuit. Figure 22 provides an example of
a battery charger design, suitable for applications that are Li-Ion (or Li-Pol) battery powered.
In the application circuit, a rechargeable Li-Ion (or Li-Pol) battery cell, that features the correct pulse
and DC discharge current capabilities and the appropriate DC series resistance, is directly connected
to the VCC supply input of the module. Battery charging is completely managed by the battery
charger IC, which from a USB power source (5.0 V typ.), linearly charges the battery in three phases:
Pre-charge constant current (active when the battery is deeply discharged): the battery is
charged with a low current.
Fast-charge constant current: the battery is charged with the maximum current, configured by
the value of an external resistor.
Constant voltage: when the battery voltage reaches the regulated output voltage, the battery
charger IC starts to reduce the current until the charge termination is done. The charging process
ends when the charging current reaches the value configured by an external resistor or when the
charging timer reaches the factory set value.
Using a battery pack with an internal NTC resistor, the battery charger IC can monitor the battery
temperature to protect the battery from operating under unsafe thermal conditions.
The battery charger IC, as linear charger, is more suitable for applications where the charging source
has a relatively low nominal voltage (~5 V), so that a switching charger is suggested for applications
where the charging source has a relatively high nominal voltage (e.g. ~12 V, see section 2.2.1.7 for the
specific design-in).
C5C3 C6
GND
SARA-R5 series
52
VCC
53
VCC
51
VCC
USB
supply
θ
U1
PG
STAT2
STA1
VDD
C1
5V0
THERM
Vss
Vbat
Li-Ion/Li-Pol
battery pack
D1
B1
C2
Li-Ion/Li-Pol
battery charger IC
D2
PROG
R1
C4
Figure 22: Li-Ion (or Li-Pol) battery charging application circuit