Been trying to code the nRF52805-CAAA-R7. The problem is that the IC is not getting detected for programming using nrf connect. Is this the problem because of WLSCP package or soldering issue or by any other means. The circuit has been taken reference from datasheet.
Hope you can provide circuit schematic diagram and PCB layout for reference.
Considering from the schematic diagram of PCB reversal, this circuit seems reasonable, but considering that 52805 is working in DCDC Config, I have the following suggestions for your reference.
1. After many experiments verified by our team, nRF52 series products have certain requirements for inductors in DCDC mode. For details, please refer to nRF52805 Product Specification v1.4 Figure 122 & Table 109 (Page 350). Under my many experimental tests, if it is necessary to ensure the reliability of nordic, The 10uH inductors on the DCC Pin need to use the 0402 package and need to guarantee 50mA of current through.
In your design, the 10uH inductance of the DCC Pin was selected in the 0201 package, which may be difficult to meet the parameter requirements in the manual.
2. Wlcsp packaged chips usually have high requirements for welding and processing accuracy. The solder pad size of the tin spraying process in the commonly used PCB processing plant (eg JLC HQ JDB) in China needs to be greater than 0.3mm. If the diameter of the solder pad is less than 0.3mm, the plating process needs to be used, please check your PCB production process. Poor production processes can lead to welding failures or unreliability.
For problem 1, you can try to remove the two inductors of the DCC Pin and make it work in LDO Config. Of course, I personally think that if the connection and software configuration are OK, the possible problem is that the welding is not reliable
Considering from the schematic diagram of PCB reversal, this circuit seems reasonable, but considering that 52805 is working in DCDC Config, I have the following suggestions for your reference.
1. After many experiments verified by our team, nRF52 series products have certain requirements for inductors in DCDC mode. For details, please refer to nRF52805 Product Specification v1.4 Figure 122 & Table 109 (Page 350). Under my many experimental tests, if it is necessary to ensure the reliability of nordic, The 10uH inductors on the DCC Pin need to use the 0402 package and need to guarantee 50mA of current through.
In your design, the 10uH inductance of the DCC Pin was selected in the 0201 package, which may be difficult to meet the parameter requirements in the manual.
2. Wlcsp packaged chips usually have high requirements for welding and processing accuracy. The solder pad size of the tin spraying process in the commonly used PCB processing plant (eg JLC HQ JDB) in China needs to be greater than 0.3mm. If the diameter of the solder pad is less than 0.3mm, the plating process needs to be used, please check your PCB production process. Poor production processes can lead to welding failures or unreliability.
For problem 1, you can try to remove the two inductors of the DCC Pin and make it work in LDO Config. Of course, I personally think that if the connection and software configuration are OK, the possible problem is that the welding is not reliable
