User's Manual

Smart Machine Smart Decision
SIM5320ALD_User Manual_V1.01 2014-08-20
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3.10.1 Sink Current Source
The dedicated pin (CURRENT_SINK) is intended for driving passive devices，such as LCD backlight, this
implementation is +5V tolerant and suitable for driving white LEDs. The high-current driver can maintain
a constant current which is set by the AT command “AT+ CLEDITST”, capable of up to 150 mA.
Table 31: Electronic characteristic
Symbol Description Min Typ Max Unit
CURRENT_SINK Input voltage 0.5 VDD 5 V
I
O
Input current - - 150 mA
Since the driver is ground-referenced current sink, the operating device it drives must form a current path
between the VDD pin and the CURRENT_SINK pin. The following figure is for users reference.
Figure 36: Current drive
Note: The sinking current can be adjusted to meet design requirement through the AT command “AT+ CLEDITST =<0>,
<value>”.The “value” ranges from 0 to 15,on behalf of the current changes from 0mA to 150mA in steps of 10mA.
3.10.2 Reset Function
SIM5320ALD also have a RESET pin (PIN4) to reset the module. This function is used as an emergency
reset only when AT command “AT+CPOF” and the POWER_ON pin has no effect. User can pull the
RESET pin to ground, then the module will reset.
This pin is already pulled up in module, so the external pull-up resistor is not necessary. A 100nF capacitor
close to the RESET pin is strongly recommended. A reference circuit is recommended in the following
figure.