I am designing the hardware circuit of spc5644A.
SRAM standby functionality is required, but I do not know how to handle VSTBY pins.
I don't know if I need an external power supply or not.
now, only an external RC circuit is connected to the processing, and there is no power supply.
I don't know if it's right.
Hi, SRAM can be backed up directly by 1V power rail or “indirectly” from 2-5.5V when standby regulator derives 1V from that automatically. It removes the need of separate 1V rail. 1-2V and 0.2V-0.95V voltage are forbidden areas.
VSTBY = 0-0.2V then standby function is disabled completely
VSTBY = 0.95-1.2V then standby regulator is disabled and standby RAM is fed directly
VSTBY = 2-5.5V then standby regulator is enabled and standby RAM is fed by 1V output of this regulator (internally).
I guess the screenshot is wrong.
Hi,Thanks for your reply.
Does whether it mean that in my circuit, I need to connect the external power supply of 2-2.5v to the VSTBY pin?
As shown in the figure below:
thanks very much.