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[FAQ] ADS1278-SP: Power on / off (up / down) sequencing requirements

Part Number: ADS1278-SP
Other Parts Discussed in Thread: ADS1278


Are there any power-on or power-off requirements or other specific power-supply recommendations for the ADS1278-SP?

  • The power-supply requirements for the ADS1278-SP, including instructions for a proper power-on startup, are described in Section 10 of the datasheet.  The power-up sequence requirements for the ADS1278-SP are only required for a proper power-on reset with no impact on reliability.  In addition, there are no power-down sequence requirements.  As long as you assert /SYNC after power-up, the device will reset and operate correctly  Per the datasheet, for a consistent device reset, the /SYNC pin should be asserted after the supplies have reached recommended operating conditions and the ADS1278 starts providing data (/DRDY asserts). 

     The key requirement for long term reliability and proper operation is to observe the Absolute maximum ratings at all times.  Either the inputs should be held at 0V during power up/down, or they can ramp with the AVDD/DVDD supply voltages.

     A critical ABS maximum requirement to meet is the AGND to DGND rating of +/-0.3V, or -0.3V<(AGND-DGND)<+0.3V.  If this voltage level is exceeded during operation, the part can be permanently damaged.  For this reason, both AGND and DGND should be connected to the same ground plane, AGND.  If separate AGND and DGND planes are used, then the ground planes should be joined with a low impedance connection directly beneath the converter.