UM220-IV NV User Manual
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4.3
Avoid Power Leakage
Module input ports of UM220-IV NV-GN include RXD and GPIO. When the module is not
powered on, if there is data input in the above ports, it will cause power leakage on the
module VCC. When the leakage voltage is higher than 1.6 V, it may cause failure of starting
up when the module is powered on.
Solution
：
When the module is not powered on, make sure that the IO ports connected on the
module is in a high-resistance state or a low level to avoid power leakage.
4.4
Reset
If the reset pin nRESET of UM220-IV NV-GN module needs to be used, the following timing
requirements must be met between the nRESET and the power supply VCC. During normal
operation of the module, pulling down the nRESET pin over the 5ms can also reset the
UM220-IV NV-GN.
VCC
nRESET
> 5ms
Figure 4-1 UM220-IV NV-GN Reset Requirement
4.5
Antenna
If the UM220-IV NV-GN uses an active antenna, the bias voltage V_BIAS is supplied to
the antenna through a feed inductor. It’s recommended to use an independent power as
V_BIAS to supply the antenna.
If the antenna power supply and the module’s main supply VCC use the same power rail, the ESD,
surge and overvoltage from the antenna will have an effect on VCC, which may cause damage to
the module. Therefore, it’s recommended to design an independent power rail for the antenna to
reduce the possibility of damage to the module.
