LTE-A Module Series
EM160R-GL_Hardware_Design 40 / 73
A simple voltage-level translator based on diodes is used on W_DISABLE1# pin and W_DISABLE2# pin
which are pulled up to a 1.8 V voltage in the module, as shown in the following figure. So, the control
signals (GPIO) of the host device could be a 1.8 V or 3.3 V voltage level and pull-up resistor is not needed
on the host side. These two signals are active low, and a reference circuit is shown below.
Host
Module
W_DISABLE2#
W_DISABLE1#
BB
GPIO
GPIO
26
8
VDD 1.8 V
NOTE:
Host
s GPIO could be a 1.8 V or 3.3 V voltage level.
R2
10K
R1
10K
VCC_IO_HOST
R4
10K
R3
10K
Figure 17: Reference Design of W_DISABLE1# and W_DISABLE2#
3.8.3. WWAN_LED#
The WWAN_LED# signal is used to indicate RF status of the module, and its typical power consumption
is up to 10 mA.
To reduce the power consumption of the LED, a resistor must be placed in series with the LED, as
illustrated in the figure below. The LED is on when the WWAN_LED# signal is at a low voltage level.
