UC6226NIS-E310E2 (QFN40) Hardware Reference Design
3
If the antenna power supply and the chip’s main supply use the same power rail, the ESD,
surge and overvoltage from the antenna will have an effect on the main supply, which may
cause damage to the chip. Therefore, it’s recommended to design an independent power
rail for the antenna to reduce the possibility of damage to the chip.
2
Attention
2.1
Power
V_DCDC_IN and VDD_IO power supply are independent of each other. There is no strict
sequence requirement for V_DCDC_IN and VDD_IO, but the lack of any one of them would
keep the chip in reset state. The rise time of V_DCDC_IN and VDD_IO when power on
should be less than 10ms and the power supply should be monotonic. After the chip is
powered on, the start-up time should be more than 230ms, otherwise the chip may work
abnormally.
Note: Although the voltage ranges of VDD_IO and V_DCDC_IN / V_CORE have intersection
and there is no strict sequence requirement, it is still recommended that the two power
domains be powered independently, because V_DCDC_IN / V_CORE has large current at
startup and the voltage range of VDD_IO is narrow; if the two domains use the same power
supply, the instantaneous high current at startup may lead to voltage drop, which may
pull down the voltage of VDD_IO below the working threshold and lead to abnormal
startup. If there are other SoCs on the board that are powered by the same source as the
UC6226NIS chip, the signal status of the host ports communicating with the chip UART
needs to be clarified. When the host wants to control the power down of the chip, the ports
connected with the chip should be set at high resistance state to prevent the chip from
consuming the power of the host even after the shutdown. PIO7 and PIO6 need
concatenate 1KΩ resistance, if the rest of the PIOs are needed, such as Reset, antenna,
recommending to concatenate resistance which is at the range of 1KΩ to 4.7KΩ (set the
resistance value according to the number of ports connected, use 1KΩ for a small number
of ports, and increase the resistance value appropriately for more ports, the maximum
value is 4.7KΩ ).
V_BCKP pin is used for backup power supply, if the application requires to support hot
start function. It needs to be powered independently. If the application does not require
hot start, V_BCKP should not be connected to an external power. Instead, it should be
connected to VDD_IO.
