Hi,
In one of our system (PCB) we are using Texas Instruments LDO IC to supply our SRAM. In the system, the FPGA is driving the SRAM (The FPGA drivers have very high drive current capability). SRAM supply is set at 3V and Output voltage of the FPGA is 3.4V. It has been found that for this 0.4V difference, the ESD Diodes are turning on and starts conducting from Input Pins towards supply. This diode current observed for this 0.4V drop is 100uA.
The core current of SRAM is around 50uA. What we measured - approx (-50uA) current at the Vcc pin, which implies that current is coming out of SRAM-Vcc pin and flowing towards regulator.
Please let me know, if this will cause problem of the LDO or not.
Regulator I am planning to use - TPS735XX (500mA - LDO).
Regards,
