Other Parts Discussed in Thread: TPS560200
Hello,
I'm using the TPS560200 as an external core supply of 1.2 V for the Infineon TLF35584. The TLF35584 enables the TPS560200 and observes its output voltage. It has a short to ground detection with 3 ms (2.7 to 3.3 ms tolerance), that expects a sufficient voltage after enabeling the external step down converter.
We built already several control boards with this setup, but now there is one board that does not start properly because of a too slow TPS560200.
The picture below shows a working combination: After reaching 3.3 V at the line UB3V3 the TPS560200 is enabled and it ramps up the line UB1V2 to 1.2 V within 2.76 ms. The time between 0.2 V and 1.0 V (1/6 to 5/6 of output voltage) is 1.485 ms, so the full soft start time between 0 V and the final voltage of 1.2 V would be 2.228 ms.
The picture below shows the failing combination: After reaching 3.3 V at the line UB3V3 the TPS560200 is enabled and it ramps up the line UB1V2 to 1.2 V within 3.63 ms. The time between 0.2 V and 1.0 V (1/6 to 5/6 of output voltage) is 2.147 ms, so the full soft start time between 0 V and the final voltage of 1.2 V would be 3.22 ms.
The circuits and all sourrounding conditions are identical, nothing is changed.
The data sheet tells:
Internal Soft-Start (VSENSE ramps from 0 V to 0.8 V): 2 ms (typical)
Unfortunately there are no Min. and Max. values mentioned. What could be the maximum ramp up time?
Is this a faulty TPS560200, or would this device still be considered OK?