Smart LTE Module Series
SC600Y&SC600T Hardware Design
SC600Y&SC600T_Hardware_Design 51 / 128
GND
BAT_THERM
VBAT
0R
100uF
NTC
VBAT
33pF
1uF
ESD
USB _VBUS
Adapter or USB
Module
Battery
C1
C2
C3
R1
D1
D2
BAT_PLUS
ESD
BAT_MINUS
GND
0805
Figure 11: Reference Design for Battery Charging Circuit
SC600Y&SC600T offer a fuel gauge algorithm that is able to accurately esti
mate the battery’s state by
current and voltage monitor techniques. Using precise measurements of battery voltage, current, and
temperature, the fuel gauge provides a dependable state of charge estimate throughout the entire life of
the battery and across a broad range of operating conditions. It effectively protects the battery from
over-discharging, and also allows users to estimate the battery life based on the battery level so as to
timely save important data before completely power-down.
Mobile devices such as mobile phones and handheld POS systems are powered by batteries. When
different batteries are utilized, the charging and discharging curve has to be modified correspondingly so
as to achieve the best effect.
If thermistor is not available in the battery, or adapter is utilized for powering the module, then there is only
a need for VBAT and GND connection. In this case, the system may be unable to detect the battery,
which will cause power-on failure. In order to avoid this, BAT_THERM should be connected to GND with a
47KΩ resistor. BAT_PLUS and BAT_MINUS must be connected, otherwise there may be abnormalities in
use of the module. Among them, BAT_PLUS and BAT_MINUS are used for battery level detection, and
they should be routed as differential pair to ensure accuracy.
3.9. USB Interface
SC600Y&SC600T provide one integrated Universal Serial Bus (USB) interface which complies with the
USB 3.0/2.0 specifications and supports super speed (5Gbps) on USB 3.0, high speed (480Mbps) on
USB 2.0 and full speed (12Mbps) modes. The USB interface supports USB OTG function, and is used for
AT command communication, data transmission, software debugging and firmware upgrade.
The following table shows the pin definition of USB interface.
