SBOU024C august 2004 – july 2023 PGA309
The PGA309 uses an industry-standard Two-Wire external EEPROM (typically, a SOT23-5 package). A 1k-bit (minimum) EEPROM is needed when using all 17 temperature coefficients. Larger EEPROMs may be used to provide user space for serial number, lot code, or other data.
The first part of the external EEPROM contains the configuration data for the PGA309, with settings for:
This section of the EEPROM contains its own individual checksum (Checksum1).
The second part of the external EEPROM contains up to 17 temperature index values and corresponding temperature coefficients for the Zero DAC and Gain DAC adjustments with measured temperature and contains its own checksum (Checksum2). The PGA309 lookup logic contains a linear interpolation algorithm for accurate DAC adjustments between stored temperature indexes. This approach allows for a piecewise linear temperature compensation of up to 17 temperature indexes and associated temperature coefficients.
If either Checksum1, Checksum2, or both are incorrect, the output of the PGA309 is set to high-impedance.