CCS: CC1310 Single-Ended Operation RX

user1338042,

I will consult the subject matter expert and get back to you shortly.

Thanks,

Seong

Thank you very much

- Could you post your schematic and the lines of code that configure frontend mode to avoid misunderstandings ?

CC1310 Single-ended mode.docx

I uploaded a document with test results and design files. Please help us analyze it. Thank you very much！

On the side first: We have not done any work on develop a single ended BOM for for 433 MHz. How did you end up with the selected component values?

When you measure RSSI in the two case, do you have a signal on the air? If not, could you test with something on the air to see if the RSSI changes? 

When I measure RSSI in two cases, no signal is generated in the air. When there is transmitter transmitting, the RSSI configured in internal bias mode is about 12 DBM higher than that configured in external bias mode. But my circuit design should be configured to external bias mode.

We use cc1310 to work in the single terminal receiving mode (0x02: single ended mode 1: external bias), and set rf_un as the receiving pin. Rx_utx provides bias for rf_n through 270nh inductance. We have two batches of ICs here. When testing on the same PCB, we found that the front batch of ICs can receive normally, and the later batch of ICs cannot receive normally. The test method is to set the parameters of the receiver through smartrf studio 7 as shown in the following figure: the bottom noise seen is very low, it seems that the LNA type inside does not work normally (compared with the IC that can receive normally, the receiver sensitivity has been tested). Since more than 10 abnormal ICs have been tested, the welding and peripheral circuit problems have been eliminated. I'd like to ask you to help me analyze it.

- Does both batches of the chip report that they are the same version/ chip if you use Flash Programmer 2? 

- What is the difference/ marking of the two batches? 

During the test, we found that in the same batch of chips, four chips were tested, two were abnormal, and the other two were normal. The version number of these chips is version 2.1.

I saw the marking of two chips，one is cc1310f128 Ti 81i a7gh G4; this reception is normal. The other is cc1310f128 Ti 81i a7gh G7; this reception is abnormal. But they are the same batch of chips. What do G4 and G7 mean? 

thank you very much！

Sorry, I read it wrong. The mark of both chips is cc1310f128 Ti 81i a7gh G4

So if I understand you correctly, you have an issue on some boards but not all using chips with exactly the same chip marking? If that is the case, have you looked into assembly issues? 

No, I use the same batch of chips, they have the same chip marking, but use four chips on the same circuit board, two chips are abnormal, two are normal.

Does the issue follow the chip, eq if you move the chip from a non working board to a working board (swap the chips) does the issue follow the chip or board? 

This problem is to follow the chip. I have tried to change the normal chip to any circuit board to work normally. When I weld the abnormal chip to a good PCB board, it is also abnormal。

Could you measure the impedance to ground from all pins to ground on a "good" and one "bad" circuit and compare? If it follows the chip it could indicate a ESD damage. 

I tested the resistance to the ground of the RFP pins of the two chips without any difference, about 4.5m ohm

Please measure the impedance for ALL pins, not just one.

TX single ended operation works normally, just Rx is abnormal

Please measure the impedance for ALL pins, not just one. 

After testing all pins, the resistance to ground of the two chips is the same about 3.8m ohm

Are you saying that you get < 1 ohm to ground for all bpis? Or do you mean that you measure 3.8 Mohm for all pins? 

Except for the power supply pin, the pins are all about 3.8m ohms

Do you have any other suggestions？  Thanks

The resistance to ground of all pins is about 3.8M ohm. In addition, we have tested that the chip with single terminal receiving abnormality can work normally and the receiving sensitivity can meet the requirements by welding it on the circuit board with differential receiving mode.

Differential receiving mode with or without external bias? 

Differential receiving mode with  external bias.