Other Parts Discussed in Thread: TPS7A20, TPS61099, REF6025, TPS784, TPS63700, TPS7A30
Hi Team,
Thank you for suggestion.
After discussion of ADS1260’s ability, it could meet/approach our requirement.
Now I have some questions of power management and design:
Mother Board: MCU and Main power-DC5V
Daughterboard: ADS1260
Power Input: DC5V/GND from motherboard of USB/AC-DC5V Adaptor (4.5V-5.5V).
→It takes risk that DC5V will under 4.75V
By the description of ADS1260_P80, it came to us some ideas for stable AVDD/AVSS:
- Unipolar
(1)AVDD:
Use boost IC to level up DC5V to 5.5V, and then buck it by LDO.
USB adaptor(4.5V~5.5V) → TPS61099(5.5V output) →TPS7A20 (5V output).
(2)AVSS = GND.
(3)VREF: REF6025(2.5V)
I get the results as bellow: (PASS) - Bipolar:
(1)AVDD:
Use LDO to buck the DC5V.
USB adaptor(4.5V~5.5V) → TPS784 (+2.5V output)
(2)AVSS:
Use negative voltage output LDO to inverter DC5V, and then buck it by negative LDO.
USB adaptor(4.5V~5.5V) → TPS63700 (~-4V) → TPS7A30 (-2.5V output).
(3)VREF: REF6025(2.5V)
I get the results as bellow: (FAIL) - because of the VIN_CM(2.8V) - Unipolar:
(1)AVDD:
Use Another DC Source like DC12V.
DC12V(11.5V~12.5V) → LDO (+5V output)
(2)AVSS = GND.
(3)VREF: REF6025(2.5V)
I get the results as bellow: (PASS)
Which of these methods do you suggest to use? (Or other suggestion?) Why?
Best Regards
Jax