14
Hardware Design
UC-00-M34 EN R1.1
D2: TVS diode, choose the TVS diode with appropriate clamping specification
according to the requirement of feed voltage and antenna voltage.
3.3
Power-on and Power-off
VCC
The VCC initial level when power-on should be less than 0.4 V.
The VCC ramp when power-on should be monotonic, without plateaus.
The voltages of undershoot and ringing should be within 5% VCC.
VCC power-on waveform: The time interval from 10% rising to 90% must be within
100 μs to 1 ms.
Power-on time interval: The time interval between the power-off (VCC < 0.4 V) to
the next power-on must be larger than 500 ms.
V_BCKP
The V_BCKP initial level when power-on should be less than 0.4 V.
The V_BCKP ramp when power-on should be monotonic, without plateaus.
The voltages of undershoot and ringing should be within 5% V_BCKP.
V_BCKP power-on waveform: The time interval from 10% rising to 90% must be
within 100 μs to 1 ms.
Power-on time interval: The time interval between the power-off (V_BCKP < 0.4 V)
to the next power-on must be larger than 500 ms.
3.4
Grounding and Heat Dissipation
Figure 3-3 Grounding and Heat Dissipation Pad
The 55 pads in the rectangle in Figure 3-3 are for grounding and heat dissipation.
In the PCB design, they must be connected to a large sized ground to strengthen the
heat dissipation.
Grounding and heat
dissipation pad
