Hi,
I'm evaluating the TPS610981EVM for our ecg logger with the ADS1298R.
Very promising, however the startup under load is a bit disappointing.
I connected an 120ohm resistor to Vbus to simulate 25mA load. With this load the tps610981 will start only when Vin > 1,18V. That's to high if you want to work with a 1 cell nicad battery.
The biggest problem is that there's an voltage on Vmain and Vsub if the tps610981 won't start.
For example 0,8V Vin, load 120ohm on Vbus will give 1.1V on Vmain and Vbus. That's enough to get the circuit behind it in very unpredictable state.
For the tps610981 the load can be switched of during startup by adding an rc delay on the Mode pin.
However, in my final design we want to use the tps610982 and there is no low power mode to do this trick.
Any suggestion to get this working?
