Hardware Development Guide of Module Product
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7
Design Guide
This chapter provides the general design guide for ZM5202, used as a reference for
the user during the design process, so that the product can reach better
performance.
7.1
General Design Rule & Requirement
When the user is designing the peripheral circuits of ZM5202, he needs to first
guarantee that the external circuit has the sufficient power supply capability, and the
USB of high-speed signal cable is required to have 90ohm differential resistance.
For the common signal interface, it is required to design according to ZTEWelink
requirements, which needs to comply with the power level of interface signal, so as
to prevent the impedance from damaging the module. The RF index of this product
itself is good, and the user needs to design the antenna circuit of the main board
and make the corresponding impedance control. Otherwise, the RF index of the
whole set will be affected.
7.2
Power Supply Circuit Design
It is required that the power supply capability of VPH_PWR on the system board
reach 2.5A or above, so as to satisfy the requirement of peak current on the module.
And the average current of the power on the system side should also reach 0.9A or
above. The power cable on the system board should be thick enough, and should
form a good reflux with the ground. Besides, in the power supply circuit design, the
user needs to add the large storage capacitor on the kilo level, to guarantee the
transient power supply capability.
