TPS7A52: What should be pay attention to if two TPS7A52 cascade together

Hi Zhizhao, 

If I understood well, you will still use the 2.5V rail coming out of LDO1 to other parts of the system, correct? 

If you are not going to use the 2.5V rail, you can just go from 3.3V to 1.8V. 

If you still need the first LDO, you can still cascade them as you are intending. You will have to arrange the output current of LDO1 so that it is enough to drive LDO2.

Best, 

Edgar Acosta

Hi Edgar,

Hi Edgar,

Hi Edgar,

Hi Edgar,

Yes, you are correct. thanks for your help. I wonder should I control the start up sequence of those two LDOs? Should I first power up LDO1 and the LDO2? 

B.R.

lucas

Hi Lucas, 

It all depends on the applied system, however due to the nature of the cascading (LDO1->LDO2), it seems natural to turn on LDO1 first and LDO2 subsequently. The EN pin will control this, however, you can enable both devices at the same time but you will not see an output of LDO2 until LDO1 provides the required input voltage to turn on. 

The datasheet talks about the sequencing of the LDO and the use of Enable, if you need more reading a upon it. 

Best, 

Edgar Acosta