chopsuei3
Newbie level 2
We are in the process of putting our modem design through PTCRB, and are failing on the SIM Vcc test, specifically the 3.0 volt test.
Some quick notes -
- We are using the SIMCOM SIM5320A, which is pre-approved for PTCRB and AT&T networks
- SIMCOM has been contacted but so far, has not been able to offer a solution
- We have also tested the evaluation board we received from SIMCOM and it also fails on the same test
Our design meets the specs the of Hardware Design recommendations from SIMCOM, specifically regarding the power supply.
View attachment 2012125154323f.pdf
We have also tried various workarounds such as larger caps to no avail.
As I understand, the steps to reproduce are as follows -
1. Module powers on
2. Module sets SIM Vcc to 1.8 volts and checks for a response
3. If no response, SIM Vcc is upped to 3.0 volts and checks for a response again
4. The testing agency is finding that the SIM Vcc voltage as it is bumped to 3.0 volts is being "over regulated" and jumps slightly over 3.0 volts, 3.08 I believe.
5. This causes the module to fail the PTCRB test specifically related to SIM power supply and over voltage.
My questions are -
1. Has anyone else experienced a similar issue with the SIM5320A?
2. Has anyone else had similar issues with PTCRB when using a pre-approved module?
3. Does anyone have any additional suggestions on how to get SIMCOM to "step up" and offer a solution?
4. Am I correct in my thinking that SIMCOM is essentially on the hook, assuming we followed the specs and referenced the eval board, for us failing PTCRB with the SIM5320A, a supposedly pre-approved module?
I understand things are tricky with hardware designs in this area, but the fact the eval board didn't pass clearly put SIMCOM on the hook?
Thanks all for your time and other ideas or comments you have,
Take care,
Some quick notes -
- We are using the SIMCOM SIM5320A, which is pre-approved for PTCRB and AT&T networks
- SIMCOM has been contacted but so far, has not been able to offer a solution
- We have also tested the evaluation board we received from SIMCOM and it also fails on the same test
Our design meets the specs the of Hardware Design recommendations from SIMCOM, specifically regarding the power supply.
View attachment 2012125154323f.pdf
We have also tried various workarounds such as larger caps to no avail.
As I understand, the steps to reproduce are as follows -
1. Module powers on
2. Module sets SIM Vcc to 1.8 volts and checks for a response
3. If no response, SIM Vcc is upped to 3.0 volts and checks for a response again
4. The testing agency is finding that the SIM Vcc voltage as it is bumped to 3.0 volts is being "over regulated" and jumps slightly over 3.0 volts, 3.08 I believe.
5. This causes the module to fail the PTCRB test specifically related to SIM power supply and over voltage.
My questions are -
1. Has anyone else experienced a similar issue with the SIM5320A?
2. Has anyone else had similar issues with PTCRB when using a pre-approved module?
3. Does anyone have any additional suggestions on how to get SIMCOM to "step up" and offer a solution?
4. Am I correct in my thinking that SIMCOM is essentially on the hook, assuming we followed the specs and referenced the eval board, for us failing PTCRB with the SIM5320A, a supposedly pre-approved module?
I understand things are tricky with hardware designs in this area, but the fact the eval board didn't pass clearly put SIMCOM on the hook?
Thanks all for your time and other ideas or comments you have,
Take care,