Other Interface; Adc; Ldo - SimCom SIM7000 Hardware Design

3.9

Other interface

3.9.1

ADC

SIM7000 has a dedicated ADC pin. It is available for digitizing analog signals such as battery
voltage and so on. Its input voltage range is from 0V to VBAT. That is the maximum measurement
range of ADC cannot exceed the input voltage of VBAT (3V~4.3V). When the voltage of the
VBAT is reduced during use, the range of ADC will also be reduced. If the input voltage of ADC
PIN exceeds its range, it is necessary to implement the resistance partial pressure on the hardware
The electronic specifications are shown in the following table.
Table 17: ADC electronic characteristics
Characteristics
Resolution
Input Range
Input serial resistance
Note: "AT+CADC" can be used to read the voltage of the ADC pin, for more details, please refer
to document [1].
3.9.2

LDO

SIM7000 has a LDO power output named VDD_EXT. The output voltage is 1.8V. This voltage can
only be pulled up for the external GPIO or power supply for the level conversion circuit.
VBAT
PWRKEY
( Input)
VDD_EXT
( Output )
Table 18: Electronic characteristic
Symbol Description
V Output voltage
VDD_EXT
I Output current
O
Note The VDD_EXT is used to the IO power in the module. The Output voltage is not
：
supported to adjust.
SIM7000 _Hardware Design _V1.04
64ms
Figure 25：Power on sequence of the VDD_EXT
Min.
1.7
-
Smart Machine Smart Decision
Min. Typ.
– –
0
1
–
Typ.
1.8
-
Max. Unit
15 Bits
VBAT V
MΩ
–
Max. Unit
1.9 V
50 mA
2018-1-31