Part Number:BQ76PL455A-Q1
Hello again;
I'm concerned about the noise/jitter I'm seeing when reading cell voltages which the EM1402 eval module. The default oversample rate (8 each) results in ~+/- 1mV of jitter on all cells, except cell #13 (top cell), which has ~+/- 5mV of jitter. However, when resetting to 32 samples, the noise drops to ~+/- 350uV on all cells except #13, which drops to ~+/- 1.5mV. My client's tech also logged this using your EM1402 GUI, and reports the same jitter. This means the "noise" is ~+/- 3 LSB, on all cells but 13, which is ~+/- 5 LSB which is unacceptable. The tests are done using both a real battery string, as well as a test board which uses a string of resistors connected to a 50V bench supply...the results are equivalent...noise.
Q1: Is this noise a known issue? If not, what could account for this?
Q2: Why are the top cell's results so much worse than the bottom cells?
Q3: The datasheet says that when idle, or in between conversions, the top cell is selected. Is this correct?
Thanks in advance.
