Hello team -
We are interested with the CSR value, if we are using this device with different input/output voltage, and different load current from what the datasheet tested, would this number still valid? Is the CSR number only apply to the steady state condition or does it apply to all conditions including when the device is ramping up (during power on)? Do you have any data to show the variation of this number due to the temperature?
Thanks!
Alex,
The CSR value is the relationship between current through pass element and current mirrors. The CSR should remain valid across ROC range. I am confirming this with the designer, just to be sure.
A couple caveats.
The CSR is characterized with currents above 500mA. When operating with lower currents, the keep alive biasing required becomes a more significant component of the Ics or Ipcl currents. Thus, more error is present in this range.
Figure 8-3 shows the temperature dependence on the CSR value, based on the load to Ipcl current.
Figure 8-7 is similar, but using Ics vs load.
During power up, if internal circuits are not properly biased up, then it is uncertain on validity of the CSR values.
It may be able to give additional help if I understood the use case intended.
Additionally, I would like to point out that there is a design calculator for the TPS7H1101A that is available.
www.ti.com/.../TPS7H1101A-CALC
A slightly updated version will be posted next week. The new version will not have any technical changes, just additional comments and summary information.
An app note to go with this is nearing completion, and should be published in a couple weeks.
Regards,
Wade
